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relinked EO W/ART 01-15-97

1. E o o E Figure 4 3 1 Numerical prediction model layer structure comparison 4 3 5 such as moisture are calculated on an LFM like grid As of 1983 the Spectral model was only able to use 30 modes or waves in its calculations In comparison the LFM provides finer resolution The Spectral model would require 40 to 45 modes to equal the LFMII model Three Layer Global Model To provide rapid computer calculations of the atmosphere for long range forecasts NWS uses the NMC 3 Layer Global model This model performs calculations on three layers from the surface to 150 millibars and carries calculations routinely out to 11 days The model output is primarily used for the 6 to 10 day forecasts Although some accuracy is lost by performing calculations on fewer levels this model is used because it requires much less computer process ing time than the more complicated models with many layers Barotropic Mesh Model Another forecast model is the Barotropic Mesh Modd It is used for rapid but fairly accu rate calculations of certain situations out to 252 hours 10 1 2 days This model assumes that the atmosphere is barotropic that is both pressure patterns and thermal patterns are in phase isoheights and isotherms are parallel no thermal advection occurs and there is no slope to pressure systems in the vertical While this concept is invalid for most pressure systems the model does handle certain sys
2. A 46 m2 d x 2 abd ham at PROG UT NA be E xv 9001102347 XUNCLASSIFIED Figure 4 2 13 MLD change prognosis 4 2 13 Sonic Layer Depth Analysis The Sonic Layer Depth SL D analysis chart as shown in figure 4 2 14 on a Mercator map projection uses shading instead of contours to indicate the depth of the maximum speed of sound near the surface The different types of shading indicate ranges of the SLD in feet no horizontal shading lines dear indicate an SLD between the surface and 50 feet widely spaced horizontal lines light indicate SLD depths between 50 and 100 feet dosely spaced lines medium indicate depths from 100 to 350 feet and very dosely spaced lines forming the darkest heavy shading indicate depths deeper than 350 feet Since the SLD may coincide with the MLD as deep as 1 500 feet the MLD analysis which contours down to 280 meters about 900 feet may be more useful for XXX 9001102300 XUNCLASSIFIED Figure 4 2 many applications Reanalysis of this chart by drawing in the 50 100 and 350 foot contours makes it a better briefing tool and equates roughly to the 15 30 and 100 meter contours on the MLD analysis FNOC also produces this chart with the contours in feet vice meters You have seen a few of the charts that are available for oceanographic applications on many different map projections and scales Th
3. 23 S AN 22 Hc A J VB is WS 1 AM EK M n Y N 7 2 9 SERM 3 8 7 27 3 Me XM Va wee I S 5 aX DNA A 9 IM re e VAN 5 SR Pa Gru 254522 2 27 2 2 Toga SA A oft dtu al e T ab RRE m 42 A Figure 4 3 2 NMC Northern Hemisphere Surface Analysis fi ae P y RE c Hemisphere analysis as transmitted on facsimile It is very similar to the North American analysis in the type of information presented The depiction and coding of various elements on these charts is as follows Z Fronts and instability lines as indicated in Frontal type intensity and character are indicated near each front in a three digit code followed by a bracket 1 It may help you to remember this as the TIC code for Type Intensity and Character but these codes are actually World Meteorological Organization WMO codes 1152 1139 and 1133 respectively These codes are given in table 4 3 1 Pressure troughs are also labeled with the phonetic abbreviation trof Z Plotted data for selected land ship and buoy stations as indicated in figure 4 3 3 Z Isobars lines of equal pressure are drawn as solid lines usually using a 4 millibar interval and a base value of 1 000 millibars I
4. F TYPE OF FRONT Quasi stationary front at the surface Quasi stationary front above the surface lysis Warm front at the surface Warm front above the surface genesis Cold front at the surface Cold front above the surface Occlusion Instability line Intertropical Front Convergence line 1139 F INTENSITY OF FRONT No specification Weak decreasing including fronto Weak little or no change Weak increasing including fronto Moderate decreasing Moderate little or no change Moderate increasing Strong decreasing Strong little or no change Strong increasing 4 3 8 1133 CHARACTER OF FRONT No specification Frontal activity area decreasing Frontal activity area little changed Frontal activity area increasing Intertropical Forming or existence suspected Quasi stationary With waves Diffuse Position doubtful NMC WEATHER ANALYSIS SYMBOLS These are th symbols most generally used by the National Meteorological Center although there are occasionally others COLD FRONT 9 COLD FRONT ALOFT WARM FRONT am STATIONARY FRONT m gym OCCLUDED FRONT COLD FRONTOGENESIS w v WARM FRONTOGENESIS STATIONARY FRONTOGENESIS 5 y COLD FRONTOLYSIS w w wv WARM FRONTOLYSIS STATIONARY FRONTOLYSIS y 4 OCCLU
5. However if the strong winds 4 1 7 and seas occur over an area of the ocean from which little or no ocean thermal data is received and atmospheric conditions are NOT considered EOTS uses the climatological mean of the layer depth in the area In such a case the LD would be too shallow for the existing conditions The TEOTS model is run once every 24 hours and is coupled to TOPS in cyclical fashion The analysis system is exacting the same as EOTS except for the coupling procedure and a different prescription of certain tuning parameters Like EOTS the FIB technique is used to combine the various types of data TEOTS is used to produce ocean temperature versus depth profiles and PLD analyses for oceans of the Northern and Southern hemispheres and for individual seas that is the eastern and western Mediterranean Sea and the Norwegian Sea Learning Objective Identify the primary elements used in FLENUMOCEANCEN s ocean frontal analysis model OCEAN FRONT ANALYSIS MODEL Ocean fronts separate water of different physical chemical and biological properties Ocean fronts are much like atmospheric fronts in that 1 they move but are much slower than atmospheric fronts 2 they may be sharply defined or difficult to locate 3 segments may be quasi stationary and 4 intensity changes occur with time Prior to the ocean frontal model being developed a large number of oceanic parameters were tried and tested to see which pa
6. The primary layer depth PLD is the first parameter analyzed by the model This is generally the depth of the seasonal thermocline The remaining 25 parameters are temperatures and vertical temperature derivatives They are ana lyzed at fixed and floating fluctuating levels The floating levels are relative to the PLD PLD 25 meters PLD 12 5 meters PLD 25 meters and PLD 50 meters Consequently when the PLD changes so do the floating levels FIB methodology is the heart of the EOTS analysis A three cyde FIB technique is used to analyze the fixed and floating level temperatures on a horizontal plane and to analyze the vertical temperature gradients between the fixed levels These analyses are based purely on information blending techniques EOTS does not consider the effect of oceanic physics and air sea interaction processes Learning Objective Identify the model that couples EOTS with atmospheric processes TOPS COUPLED EOTS TEOTS ANALYSIS MODEL The coupling of ocean thermal analyses to atmospheric forces is accomplished via the physics incorporated in the Thermodynamic Ocean Prediction System TOPS model The coupling prevents mixed layer depths and mixed layer temperatures from following strictly climatologi cal trends For example consider a rapidly deepening low pressure system with strong winds and heavy seas Such a system normally produces strong mechanical mixing which in turn produces deeper layer depths
7. aircraft icing and in thunderstorm forecasting The most severe icing occurs at temperatures between 09 and 10 C With regard to thunderstorms lightning strikes are most prevalent at the freezing level Pilots must be advised of this when their aircraft is cleared through a thunderstorm area Freezing level charts are also used to forecast changes from rain to snow and vice versa Learning Objective Identify FLENUM OCEANCEN oceanographic analysis models and their uses EXPANDED OCEAN THERMAL STRUCTURE EOTS ANALYSIS MODEL The EOTS model is used to produce tempera ture versus depth surface to bottom analyses Sea Surface Temperature SST analyses and layer depth analyses EOTS provides the input for most of the acoustic predictions generated at FLENUMOCEANCEN Data Input The daily real time global data base used by EOTS consists of 150 to 200 XBT observations 1 200 to 2 000 SST observations ship injection or bucket and 50 000 to 80 000 satellite SST readouts 4 1 6 EOTS can also accept synthetic data inputs such as horizontal surface and subsurface thermal gradients The regional centers supply the synthetic data in message form Analysis EOTS analyzes 26 thermal parameters in the upper 400 meters of the sea on a 63 by 63 or 125 by 125 vertical grid Below 400 meters the thermal field is derived from climatology and is modified to blend smoothly with the temperature profile analyzed above 400 meters
8. derived data a good portion is provided to DOD users as either facsimile charts or electronically transmitted bulletins In this lesson we will discuss only a few of the thousands of charts and bulletins provided by NWS AVAILABILITY OF NWS PRODUCTS TO NAVAL OCEANOGRAPHY COMMAND UNITS How do you as an Aerographer receive these facsimile charts and electronic bulletins Most of 4 3 2 the NWS products you will use will come from NMC through the Department of Defense Defense Communications System DOD DCS Global Weather Communications System s GWCS Automated Weather Network AWN The hub of the AWN is the Automated Digital Weather Switch ADWS at Carswell AFB Carswell is connected with nearly every DOD weather facility in the continental United States NMC data and bulletins are sent directly from ADWS to your COMEDS printer or computer terminal Additional data is sent to Fleet Numerical Oceanography Center FNOC Monterey for processing and further distribution via the Naval Environmental Data System NEDS to Naval Oceanography Command NOC Centers Facilities or Detachments Rota Hawaii and Guam all may receive NWS data and bulletins via the Naval Environmental Data N et work NEDN NWS facsimile charts are retransmitted on the Air Force Digital Graphics System AFDIGS a second major component of the DOD DCS GWCS NOC Centers may receive this data via land line circuits or satellite and retransmit selected data
9. in the United States As a member of the World Meteorological Organization WMO NWS also shares selected data and products with all other member nations in the WMO via the WMO data collection computer system based in Geneva Switzerland Learning Objective Identify the types of National Weather Service products and the routine methods used to distribute these products to Naval Oceanography Command units and Fleet Aerographer s Mates GENERAL TYPES OF NATIONAL WEATHER SERVICE PRODUCTS Most of the observational and prognostic data routinely received from foreign countries by NWS is in the form of digital messages although some digital charts are received The National Weather Service computers at the National Meteorological Center NM C automatically receive and process all data received from North America and the remainder of the world Selected raw observa tional data is routinely used in various numerical prediction models to produce both graphic charts and numerical bulletins NWS also receives copious amounts of digital satellite imagery and computer derived digital data from another branch of NOAA the National Environmental Satellite Data and Information Service NESDIS A large portion of the data received at NMC and the products produced by NMC are available tothe Department of Defense While most of this data is provided to DOD as digital data fields intended to load a computer with semi processed data or computer
10. including the Navy and Marine Corps weather offices The NWS Technical Procedure Bulletins TPBs series describes in detail changes implemented in the various analysis and prognosis models formats for various bulletins a breakdown of the coding used in many bulletins and techniques for making best use of informa tion in the bulletins SATFAX and NAFAX schedules are also issued as TPBs TPBs should be read by every meteorological technician and forecaster Unfortunately when TPBs are received too often they are pigeon holed somewhere or discarded instead of being held as ready reference material The best overall listing of facsimile product availability is contained in AWSP 105 52 Volume Facsimile Products Guide on microfiche This lists both NWS and AFGWC facsimile products and provides information on MANOP headings if they have been assigned area coverage and on what data is provided ASWP 105 52 Volume 111 Weather Message Catalog provides similar information on all standard and special use bulletins produced by the NWS AFGWC and Naval Oceanography Command units as well as bulletins available from foreign countries MANOP headings area coverage coding and other specifics of each bulletin are provided if available This also is available on microfiche and is updated quarterly Volume II in this series is the Weather Station Index worldwide coverage and does not apply to this lesson Schedules for the fo
11. non existent or are termed impossible the model bases the analysis of the area on the first guess data field If the first guess data field in the area is in error the analysis ends up in error Such errors are especially evident when atmospheric changes take place in an explosive manner For example if the model does not have an SLP observation s in an area undergoing rapid deepening or if it discards a report or reports in an area as impossible the first guess values are used If the first guess values in the area do not reflect explosive deepening the area will be incorrectly analyzed Any incorrectly analyzed region should be brought to the attention of the FLENUMOCEANCEN duty officer in order that the analysis can be corrected Such corrections often require the insertion of a bogus report s into the data field These made up reports are designed to correct the analysis in a region in question BLENDING Blending is the model step that corresponds to the drawing of isolines by hand To cover data sparse regions grid point values are adjusted and spread to surrounding grid points using gradient knowledge and mathematical gradient formulation Blending spreads the data from high reliability grid points grid points with values based on observations to those having lower reliability grid points based on the first guess analysis The degree of spreading is increased with higher reliability in the gradient COMPUTING RELIAB
12. of a typical Radar Summary The following information is routinely represented on radar summary charts 2 Areas of radar observed precipitation are outlined with a solid line and shaded Isoecho lines are drawn at levels 1 3 and 5 Areas of light snow and drizzle usually do not show up well on radar and may not be indicated Levels 3 and 5 contoured within the shaded areas indicate heavier precipitation Z Area movement or the movement of a general area of precipitation is indicated by a wind barb showing the direction and speed of movement Z Cdl movement or the movement of the strongest individual cumulonimbus cloud cell is shown by an arrow indicating direction and a speed in knots printed near the point of the arrow Z Cloud cell tops are indicated by three underlined digits representing the height in hundreds of feet A thin line is usually drawn from the end of the underline to a location within a shaded precipitation area to show the location of the measurement Cloud bases are shown with three overlined digits Z Weather Watch areas or boxes are endosed with a dashed line and labeled with the watch number The valid time of each watch area will be printed along with the watch number next to the legend in the lower left corner of each chart OTE 2162 THU JUN 1981 16 TOTAL STATIONS 2 FOR 940 0 gt eam EE m 1000 FT AND OR V BY LESS TH
13. via their facsimile broadcasts to the fleet NWS operates the direct Satellite Facsimile SATFAX broadcast which is currently used by most U S Marine Corps weather detachments and many stateside NOC Detachments NWS also operates the National Facsimile NAFAX circuits which are available at many CONUS NOC Units The NAFAX circuits are being phased out and replaced by SATFAX Additionally NWS main tains localized and specialized facsimile broad casts such as the Inter Alaska Facsimile AKFAX circuit the Suitland Honolulu circuit the Tropical Analysis TROPAN circuit and a special circuit for Puerto Rico and the Virgin Islands These are available to DOD users of these circuits contain regional and global charts produced by NWS AVAILABILITY OF NWS PRODUCTS TO FLEET AEROGRAPHER S MATES The NOC fleet facsimile broadcasts are composed mostly of FNOC produced charts Supplemental charts are received directly from NMC via the NWS SATFAX broadcast the NWS Digital Facsimile DIFAX broadcast or received indirectly from NMC on the AFDIGS broadcast from the Air Force Global Weather Center AFGWC The Navy s fleet meteorological data broadcast part of the Fleet Multi channel Satellite Broadcast originates at Carswell AFB with data received from NWS This data is supplemented with data inserted by the NOC Centers While most of the data transmitted from outside the United States is received at the NOC Centers on the NEDN
14. wind and frontal analysis are produced every 6 hours beginning at 00007 An example of an FNOC surface pressure preliminary analysis SFC PRELIM is shown in f gure 4 2 1 This chart covers about an eighth of the globe and provides an initial look at the pressure systems Highly smoothed isobars are drawn every 4 millibars hectopascales High and low pressure centers are indicated by H and L with the exact center v ETT 87771 ELIM PR 366 YU Fhe MNT PUES Figure 4 2 1 Surface preliminary analysis 4 2 2 5 _ a I walan lar 2285 indicated by a mark The central pressure is printed to the right of the mark in tens units and tenths of millibars Shortly after the SFC PRELIM is produced the computers complete the more detailed surface pressure and surface wind analyses These two analyses are transmitted to users over the NEDN as separate data fields and then are combined at a NEDS terminal to produce a composite chart Figure 4 2 2 shows a more detailed combined surface wind and pressure analysis a Global Band tropical analysis This Mercator map projection is typical of charts produced for users in the tropics Note the smaller scale this chart covers only about one fifteenth of the globe The isobars are drawn every 4 millibars They show a much more detailed representation of the pressur
15. 7 products distributed to the fleet are tailored by the NOC centers FREEZING LEVEL CHARTS The FNOC computers calculate the freezing level during the analysis and during the fore cast model runs Freeing levd analyses and prognostic data fields are produced routinely twice a day out to 72 hours Figure 4 2 7 shows a typical freezing level prognostic chart Solid lines depict only the lowest freezing level The contour labeled 00 indicates the freezing level at the surface Additional contours are depicted every 500 meters and labeled in hundreds of meters Since flight weather briefs require freezing levels in feet the user must convert the heights in meters to feet Always be alert for signs of multiple freezing levels The most dangerous aircraft icing severe clear ice can occur when liquid precipitation falls into a layer of freezing air Precipitation in areas with multiple freezing levels may indicate severe dear icing This chart will not indicate those situations properly Besides producing meteorological analyses and forecast charts FNOC also produces many 8 2 1 1 o oceanographic charts Several of these oceano graphic charts are discussed in the next section Learning Objective Interpret various oceanographic charts produced by FNOC OCEANOGRAPHIC CHARTS The oceanographic charts produced by the computers at FNOC provide analyses and fore casts of conditions that dir
16. AN 3 HI CONTOURED HITHOUT SHADING tii GREATER gt THAN OR EQUAL T 1000 TQ LESS THAN EQUAL T0 3000 FT AND OR VSBY GREATER TAN OR EQUAL TO is LESS Yhan QR sm aee o C nrounsO ver u GREATER VFR AREAS WITH e r NATIONAL HEATHER SERVICE 16Z THU 04 JUN FRONTAL POSITION FROM PREVIOUS HOUR 0A e qe ice 3000 FT ANS GREATER THAN 5 m ae Figure 4 3 4 Weather Depiction Analysis TIE hy Wd 1 A N RRA gt re 9 ai 1 2 252 97488 ssm 229 in 0 1 LEGEND i3 2 SNABIN ECHQ AREAS m 1 EU CONTOURS AT INTENSITIES 1 3 ae o TOPS 099 Basts 999 1005 DF PREF TX A ALFT TOF 1 HER HATCH AREAS LX CSI HUNT MEAS SL IMES PEWIBNTS ERC hvnf CELLS AARDUS SPEED NONE 22 ee mips apron L 2n 25 UL boc 0119 STARE VS Figure 4 3 5 Radar Summary Analysis 2 The following abbreviations are used on the charts to darify reports or information R Moderate Rain RW Rain Showers ZL Freezing Drizzle Used after R S RW SW ZL or ZR indicates light precipitation TRW Moderate Thunderstorms TRW He
17. CAL OCEANOGRAPHY CENTER METEOROLOGICAL AND OCEANOGRAPHIC PRODUCTS The Fleet Numerical Oceanography Center FLENUMOCEANCEN or FNOC Monterey California produces computer generated meteorological and oceanographic charts and messages for use by Naval Oceanography Com mand NOC units the Navy and the Department of Defense The data from which meteorological and oceanographic charts are derived is transmitted from FNOC to NOC Centers via the Naval En vironmental Data Network NEDN to Naval En vironmental Display System NEDS terminals The NEDS units AN FMC l store the data NEDS operators are then able to produce the charts on their NEDS terminals They are also able to transmit any or all of this data to NOC facilities and or detachments having a NEDS 1A unit AN FMC 2 The centers can also include these charts as part of their facsimile transmission schedule to the Fleet Many Department of Defense users other than the Navy and other U S Government agencies such as the U S Coast Guard and National Oceanic and Atmospheric Administration OUTLINE Surface weather charts Upper air charts Freezing level charts Oceanographic charts Message products Acoustic Range Prediction Products NOAA activities receive FNOC charts and products via the joint Navy NOAA Oceano graphic Data Distribution System NODDS This system allows charts and products to be received on desk top computers using a telephone modem The m
18. DED FRONTOLYSIS 4 INSTABILITY SQUALL LINE TROUGH RIDGE WADA AYIA CONVERGENCE LINE Sg NMC SURFACE PLOTTING MODELS nu d Cu TT C PP ww tppo Ta Ta C RR SeSps sp 3 P Py Hy Hy LAND SHIP du du Py Hy Hy TINCA PPP ww tppa Figure 4 3 3 NMC weather analysis symbols Z Visual Flight Rules VFR condition areas prevail in all other areas not surrounded by solid lines These are areas where the ceilings are greater than 3 000 feet and the visibility is greater than 5 statute miles Z Surface frontal positions from the previous hour are drawn using the standard NMC depictions Z Plotted data for each terminal includes 1 significant weather symbols 2 visibil ity in statute miles 3 total sky cover in tenths and 4 ceiling height All ceiling heights of the lowest layer with 5 10 or greater coverage are plotted When total sky cover is less than 5 10 the height of the lowest scattered layer is plotted Visibilities over 6 statute miles are not plotted Z Date and time of the analysis are found in the identification block in the lower left corner of each chart Radar Summary The Radar Summary chart is a computer analysis of digital radar reports and is used as mainly as a briefing aid This chart is produced hourly from radar reports taken 35 minutes past each hour Figure 4 3 5 shows an example
19. ILITY FIELD OF THE BLENDED PARAMETER In this step the computer assigns weight factors to the blended grid point values The higher the weight factor the higher the reliability of the value For example a grid point value based on an observation s normally has a higher weight than a grid point value based on an extension of a gradient The reliability of all grid points is increased through the blending process REEVALUATION AND LATERAL RE JECTION 1 step 5 FIB uses the blended parameter field and the weighted values to reevaluate each piece of information entered into the analysis Reevaluation is a quality control done on each observation A statistical value is computed for each report and is compared to the actual value The statistical value measures how accurate a report really is compared to its expected accuracy as given by its assigned weight factor The lateral rejection check takes place when each grid point value with its weight is removed individually from the grid and compared with what remains or the background If the report is within its expected reliability range no change is madetoits weight If the value is greater than the expected range but within some upper limit its weight is reduced If the value exceeds the range limits the report is rejected that is its weight becomes zero and it has no effect when the next assembly and blending is done REANALYSIS After the grid point values are r
20. North America The resolution of grid C is 84 kilometers at 45 much finer than the LFMII The larger amplitude atmospheric waves are calculated on the course grid A When these features enter the area covered by the finer grids information is exchanged and calculations proceed on all three grids with constant error checking The boundary layer is only 35 millibars above the surface or about 986 feet AGL Figure 4 3 1 shows the vertical structure of the NGM with the thickness in millibars of each of the layers We expect that by the end of 1990 the NGM output will entirely replace the use of the LFMII output for regional forecast products in the United States Spectral Model Since 1980 NMC s Spectral model has run as the primary operational hemispheric and global prediction model The model routinely uses 12 layers of the atmosphere sed figure 4 3 1 and as of 1983 calculates out to 60 hours Resolution is somewhat finer in the lower atmospheric levels than in the stratosphere and the overall resolution of the model is slightly finer than that of the original LFM model Instead of performing calculations in the horizontal in a grid like the LFM this model calculates modes of the atmosphere which can be related to calculating the wave progression and amplitude changes of the waves in the atmosphere Some parameters 4 3 4 SPECTRAL NGM LFM 12 LAYER MODEL 16 LAYER MODEL 7 LAYER MODEL o o M 4
21. UNIT 4 METEOROLOGICAL AND OCEANOGRAPHIC PRODUCTS AND THEIR INTERPRETATION FOREWORD Today s Aerographer s Mates use vast amounts of meteorological and oceanographic charts and messages All of these products contain valuable information The charted products display information with numbers symbols lines and shaded areas on a map background M essages may either present information in plain language abbreviated language code or alpha numeric plots As an Airman you learned how to decode or interpret many different types of observation messages while studying to become a Meteorological Technician Observer Plotter As an Aerographer s Mate Second Class performing the duties of an Analyst Forecaster Assistant and later as an Analyst Forecaster you will be required to interpret information presented in many different types of charts and messages In this unit we will present information that will help you to interpret the meteorological and oceanographic messages and charts most frequently used by Navy Analyst F orecasters In Lesson 1 we will discuss the meteorological and oceanographic models used by the computers at the Fleet Numerical Oceanography Center FNOC Monterey California In Lesson 2 we will discuss the major meteorological and oceanographic products available from the FNOC computers The major numerical models in use by the National Weather Service NWS and the products available from NWS are discussed in Lesson 3 L
22. air analysis fields are used Numerous types of data are used in the analysis Convent ional radiosonde and aircraft reports are used in both the wind and temperature analyses The wind analysis also includes Pibal reports and satellite derived winds Vertical temperature profiles obtained from satellite radiometers are used in the temperature analysis The temperature profiles greatly increase the data base in the Southern Hemisphere Southern Hemisphere Polar Stereographic Analysis This analysis uses the same technique as is used in the northern hemisphere upper air analysis A major difference is in the amount of satellite data used and the greater weight placed on satellite derived 1 000 to 300 millibar thickness values 41 4 Learning Objective Recognize the most common charts produced using the scale and separation pattern model and the major problem with the model SCALE AND PATTERN SEPARATION MODEL The circulation at any level within the atmosphere shows features of varying scale size and pattern At the surface there are micro lows troughs ridges migratory cydones and anti cyclones and the large scale semi permanent pressure systems Aloft there are troughs ridges highs and lows with varying wave lengths and amplitudes These in turn are all part of the still larger scale system the planetary vortex Interaction of features either at the same level or at differing levels is a major problem faced by
23. ajor benefit derived from computer generated charts is the time saved by not having to plot and analyze the data A major problem with these charts is that analysts and forecasters work from finished products and do not analyze the observations used to produce the charts A great deal of meteorological insight is lost when weather observations are not studied Fleet requests for products are sent to FNOC over the AUTODIN or NEDN communications networks using the Automated Products Re quests APR format Learning Objective Interpret various surface weather charts produced by FNOC SURFACE WEATHER CHARTS Manually prepared surface weather charts are quite different from the computer generated surface weather charts At the very least manually produced surface charts will include weather station plots isobars and fronts A more in depth chart may contain a neph analysis cloud analysis air mass designa tors and a weather depiction analysis At their best manually produced surface weather charts are highly colorful and extremely informative Computer generated surface charts do not contain nearly as much information as the manually produced charts They do provide an isobaric analysis they may or may not indude weather station plots or low level wind plots and they do not contain fronts Fronts must be hand drawn on these charts Surface Weather Analysis Charts Synoptic charts of surface pressure
24. and identify the manual that describes the product format and interpretation guide ACOUSTIC RANGE PREDICTION PRODUCTS FNOC provides acoustic range prediction products in support of active and passive sonar systems The Acoustic Sensor Range Prediction ASRAP and the Predesignated High Interest Tactical Area PHITAR products were developed to support passive systems Active systems are supported by the Active ASRAP and the Ship Helicopter Acoustic Range Prediction System SHARPS products Although briefly described in this section these products and their applications are thoroughly described in the classified NAVOCEANCOMINST C3140 22 The NAVOCEANCOM Environmental Tactical Support Products Manual U Request pro cedures are found in the Automated Product Re quest APR User s Manual ASRAP Products ASRAP is an omni directional product that provides the tactician with expected acoustic ranges for user specified or default source depth receiver depth frequency combinations This product supports all aircraft and surface ship passive sonar systems and is available in four modes Z ASRAPC Frequency Mode the various source depths and receiver depths are depicted for each frequency 7 ASRAPR Receiver Mode the various frequencies and source depths are depicted for each receiver depth Z ASRAPS Source Mode the various frequencies and receiver depths are depicted for each source depth 2 ASRAPV VLAD Mode for
25. ant wave height maximum wave height whitecap probability and primary and secondary wave direction and period These fields are transformed to a variety of map projections 4 1 8 Learning Objective Identify the model used to produce SST analyses SEA SURFACE TEMPERATURE ANALYSIS MODEL Any of the environmental models maybe used to produce analyses and prognoses for ocean waves sea surface temperature and ocean thermal structure Most often the Navy Opera tional Regional Prediction System NORAPS is used to produce regional SST analyses The reported sea surface temperatures from ships satellite reports and dimatology are weighted and combined for a data field The data is then evaluated in a similar manner as any other data in the surface analysis routine SUMMARY In this lesson we have discussed some of the analysis techniques used by the computers at FLENUMOCEANCEN This information has been discussed so that you the analyst will have a basic knowledge of the strengths and weaknesses of the computer analyses you will be using With this knowledge you will be able to make informed adjustments to information depicted in FLENUMOCEANCEN s computer analyses UNIT 4 LESSON 2 FLEET NUMERICAL OCEANOGRAPHY CENTER METEOROLOGICAL AND OCEANOGRAPHIC PRODUCTS OVERVIEW Identify and interpret major meteorological and oceanographic products produced and issued by the Fleet Numerical Oceanography Center FLEET NUMERI
26. ant pressure charts The differences in air density thickness are shown by isoheight lines or lines of equal height of a constant pressure surface above mean sea level 4 3 12
27. ar to the LFM MOS output in both graphics and bulletin products The main difference is that Perfect Prog uses the forecast situation from the NGM model vice the LFMII The situation is then compared to the historical conditions and probabilities for various types of weather occurrences are calculated NGM Perfect Prog forecasts are referred to as NGM Probability Forecasts in some publications and product listings Learning Objective Identify parameters on the most frequently used National Weather Service facsimile charts PARAMETERS ON NWS FACSIMILE CHARTS Although the National Weather Service produces numerous facsimile charts to distribute oceanographic and meteorological information to its own forecast support offices DOD and public users we cannot describe all of those charts in this training manual To do so we would need to publish a separate volume dealing with nothing but the NWS facsimile products In this section we will discuss some of the most frequently used products Surface Analysis The NWS s NMC produces four Northern Hemisphere surface analyses and eight North American surface analyses daily at synoptic and synoptic intermediate hours All of these analyses are plotted and roughly analyzed by the computers then reanalyzed by trained analysts Figure 4 3 2 shows a typical section of a Northern 4 3 6 Lev 2 IN n 2 Q SPA 255 P sel 9 A 5 5 52
28. at values and their gradients do not unduly influence each other on opposite sides of mountains or land features For example cold air that piles up on the north side of the Alps does not carry over to the south side SST analyses for selected regions of the Gulf Stream Labrador and Kuroshio currents are conducted using 1 8 size fine mesh grids The disassociation parameter is also applied to these analyses because the temperature structure on opposite sides of peninsulas etc can be markedly different SPHERICAL SURFACE PRESSURE AND WIND ANALYSIS is also used in the construction of the spherical surface pressure and wind analysis This analysis is produced on a spherical grid every 6 hours It is a combination of a surface pressure analysis and a wind analysis The input data include ship reports up to 6 hours old land reports with islands receiving more relative weight low level satellite winds decreased by 20 of their estimated value satellite derived winds are used in the area between 20 N and 20 S only and coded isobaric analysis messages from various Southern Hemisphere meteorological organizations The FIB produced Northern and Southern hemispheres sea level pressure analyses are interpolated onto a spherical grid and a first guess analysis is produced for the regions poleward of 20 and S The first guess pressure analysis is then blended with dimatology and the previous spherical pressure analysis to
29. avy Thunderstorm TRWX Intense Thunderstorm TRWU Thunderstorm Intensity Unknown SLD Solid Line Thunder storms following any of above intensity increasing NE No echoes ROBEPS Radar operating below established performance standards S Moderate Snow SW Snow Showers ZR Freezing Rain Used after R S RW SW ZL or ZR indicates heavy precipitation TRW Weak Thunderstorms TRW Very Heavy Thunder storm TRWXX Extreme Thunderstorm LEWP Line Echo Wave Pattern HOOK Hook Echo implies fun nel cloud or tornado following any of above intensity decreasing OM Radar out for mainte nance NA Report not available Z The valid time date and day of each chart are located in the lower right corner of the chart Upper Air Analysis Charts The NMC produces several upper air anal ysis charts twice daily at 00007 and 12007 All are done by the computers with limited analyst intervention Output from the com puter may be grouped into two general cat egories the North American charts with plotted data and the Northern Hemisphere charts without plotted data Figure 4 3 6 shows a typical North American upper air analysis with plotted data The North American charts are routinely available for the stan dard levels 850 700 500 300 and 200 millibars The Northern Hemisphere charts are produced for the 500 and 300 millibar levels These upper air analyses are sometimes referred to as const
30. c Clark AFB Republic of the Philippines for the Far East and the Indian Ocean Croton AB England for Europe the eastern North Atlantic and Barents Sea Incirlick AB Turkey for Southern Europe the Mediterranean and the Middle East Homestead AFB Florida for the Caribbean Central America and southern United States and one additional site for the South Atlantic Information on frequendes and data content is contained in AWSR 55 9 Requests for frequencies and special support should be addressed to COMNAVOCEANCOM Additionally limited NWS charts are available on the satellite Weather Facsimile WEFAX broadcasts from the geostationary E arth orbiting satellites GOES operated by the National 4 3 3 Environmental Satellite Data and Information Service NESDIS Several different NWS charts are routinely retransmitted by the Soviets the British the Germans and the Italians on their meteorological HF broadcasts INFORMATIONAL SOURCES ABOUT NWS PRODUCTS AVAILABILITY AND SCHEDULES Now that you know that a multitude of NWS products are available for your use how do you find out the purpose of all these charts and bulletins National Weather Service Forecasting Hand book No 1 Facsimile Products describes many of the different NWS analysis and prognosis charts in detail and gives descriptions of the numerical prediction models used to produce these charts This book should be available in every U S weather office
31. ced for the mid latitude users The winds are plotted on a grid with spacing between grid points of about 5 degrees latitude at 15 N or about 300 nmi As you look farther north you E i oum Feo 9 Figure 4 2 3 Frontal depiction analysis 4 2 4 may notice that the same grid spacing is equivalent to about 7 degrees latitude at 50 N or about 420 nmi This means that at 15 N the wind plot represents an average wind for a 90 000 square mile area while at 50 N the wind plot represents an average wind for a 176 400 square mile area or about one half the resolution You must keep that in mind when using these charts to make your forecast Sometimes it is preferable to use a geostrophic wind scale and isobar spacing to determine forecast winds instead of the winds plotted on the chart Gtr gt 412 us Ten SFE n Ta j N 4 45 ES E 120 T2 24 A Qu ie di de A Learning Objective Interpret FNOC constant pressure and freezing level charts UPPER AIR CHARTS The upper air analyses and prognosis charts are all very similar Analyses are routinely produced for the 850 700 500 400 and Pd 8 JUL X wo BN Figure 4 2 4 Surface wind and surface pressure prognosis 4 2 5 300 and 200 millibar levels Figure 4 2 5 shows an 850 millibar analysis on a polar stereographic map projection as used
32. e pattern than is shown in the SFC PRELIM analysis although smoothing may eliminate minor yet significant pressure deviations Winds are represented on this chart by standard wind plots on a five degree grid They do not represent actual reported winds but computer averaged winds over a five degree square area Neither of the FNOC surface analyses depicts fronts or troughs Figure 4 2 2 Surface wind and surface pressure analysis 4 2 3 The frontal depiction analysis GG Theta is shown in figure 4 2 3 This example is an analysis from central Asia to central North America The frontal positions are depicted with contours of percent probability of the frontal location It is up to the user to determine the actual frontal placement as well as the type of discontinuity warm front cold front occlusion or pressure trough This analysis does not always provide the user with clear cut frontal boundaries Normally fronts are located where the isolines are packed tightly around an elongated central core The isolines parallel all fronts except occluded fronts Theisolines lie more or less perpendicular across occlusions Usually the higher probabilities surround areas where reports show strong discon tinuities such as large temperature changes large wind speed and direction changes or marked pressure rises and falls The higher probability areas tend to indicate the locations of the more dynamic fronts Notice in the tro
33. e basic presentation of features on these charts are all very similar regardless of the resolution used J ust about every data field that is presented in chart form is also available as a message of gridded point values which may be transmitted over various communications circuits to suit your requirements Sire vga a ALTSTS VALID Nap 0 14 51 analysis 4 2 14 Learning Objective Identify the sources to obtain information on the request procedures for message format gridded data fields MESSAGE PRODUCTS AWSP 105 52 volume 111 Weather Message Catalog lists MANOP headers for many pre designated FNOC meteorological and oceano graphic products in gridded format ranging from surface winds and upper level winds to highly detailed sea wave spectrum predictions for specified points In addition Automated Product Request APR User s Manual FLE NUMOCEANCENINST 3140 3 describes pro cedures for requesting various data fields and specialized meteorological and oceanographic products A new instruction General Acoustic Conditions Depiction System User s Guide FLENUMOCEANCENINST 3145 3 describes various acoustic conditions graphic products as well as alphanumeric gridded products available from FNOC via NEDS NODDS and AUTODIN message Learning Objectives Identify the Acoustic Range Prediction products available from FNOC identify the manual that describes the request procedures for the products
34. e reported as the direction the wind is coming from wave directions are reported as the direction the waves are moving to Most of the Fleet Facsimile Broadcasts also include charts manually produced at the Oceanography Centers that include swell wave heights These are the Combined Sea Height charts The combined sea height is actually the highest wave height at the points where the significant sea waves merge with the swell wave Where these waves meet a higher wave is formed than either the highest sea wave height or the highest swell wave height alone The combined sea height C is calculated from both the sea wave height either the reported significant sea wave height or the computer calculated significant sea wave height and the swell wave height by the formula V seas swell The combined sea height charts also indicate the prevailing wave direction with an arrow It is important that you know the differences between the combined sea height chart and the significant wave height chart They are not 91102259 SUNCLASSIFIED 2233 ge 5 AE c 277 Jy el es 3 Di E S de vol fare PM 27 3 x 22 TM VS intended to show the same parameters and should rarely look exactly alike Comparison of both types of charts for corresponding times will give you a good overall picture of the swell wave the sea waves and the general sea
35. ectly effect daily opera tions in the Navy s antisubmarine warfare effort as well as routine ship operations Computer interface with the climatological data base and with data files of current and near current oceano graphic observations allows development of a FREEZING LEVEL 24HR PROG UT 002 12 JAN ma i ma N K 7 Figure 4 2 7 Freezing level prognosis 4 2 8 much more accurate depiction of oceano graphic features than is possible by a single oceanographic analyst forecaster However over smoothing of the data fields on the large scale charts routinely transmitted via facsimile may mask significant details necessary for certain applications Products transmitted over the unencrypted facsimile broadcast may be inten tionally over smoothed so as not to yield details of significant oceanographic features to non NATO naval forces who routinely intercept and use the data from the broadcast For applications requiring greater accuracy and detail the Automated Product Request APR system should be used to receive oceanographic products via encrypted channels In this section we will discuss the Sea Surface Temperature analysis the Sea Surface Tempera ture Anomaly analysis the Significant Wave Height analysis and prognosis the Mixed Layer Depth analysis and prognosis and the Sonic Layer Depth analysis charts All of these products are routinely available on Mercator projections or as polar stereogra
36. eevaluated and new weights are assigned the reanalysis step begins This step is no more than a repeat of the assembly step using the first guess field and the reevaluated data The new field may be reevaluated and reanalyzed two or three times before the computer accepts it and sends it to the output section where it is stored for transmission and for input into other programs Learning Objective Identify other models and products to which FIB is applied FIB Applications The FIB technique is also used with the Navy Operational Regional Atmospheric Prediction System NORAPS model It is applied to FLENUMOCEANCEN s finemesh grids NAVY OPERATIONAL REGIONAL AT MOSPHERIC PREDICTION SYSTEM 5 of this writing NORAPS is used in operational data runs to provide 36 hour fine mesh forecasts for four geographical regions the Mediterranean Sea 4 1 3 western Pacific Ocean Indian Ocean and the northwestern Atlantic Ocean The Med and WestPac regions are run at approximately 03Z and 15Z while the Indian Ocean and NW Atlantic regions are run at 07Z and 19Z Data from two other regions are also run through the NORAPS program the Eastern Pacific and the North Pole However these two regions are available to the Fleet only upon request The number and time of NORAPS model runs changes with changing Fleet requirements FINE MESH ANALYSIS AND PROG NOSIS Fine mesh products incorporate a terrain disassociation parameter so th
37. esson 4 addresses the Terminal Aerodrome Forecast Code TAF In lesson 5 we discuss products available from the Tactical Environmental Software System TESS and the Optimum Path Aircraft Routing System OPARS products are discussed in Lesson 6 4 0 1 UNIT 4 LESSON 1 FLENUMOCEANCEN ANALYSIS MODELS OVERVIEW Identify FLENUMOCEANCEN environmental analysis models and analysis techniques FLENUMOCEANCEN ANALYSIS MODELS There are many computer generated surface upper air and oceanography products available from the FLENUMOCEANCEN You should be aware of the available products have an understanding of how they are derived and how they are interpreted The heart of computer generated environ mental products is the model or program used to produce the products Environmental models are used in analyses prognoses and special programs and they are constantly being updated or refined to produce the best possible product OUTLINE Surface analysis model Upper air analysis model Scale and Pattern Separation model Frontal analysis model Tropopause height analysis model Freezing level analysis model Expanded Ocean Thermal Structure EOTS analysis model Thermodynamic Ocean Prediction System TOPS Coupled EOTS TEOTS analysis model Ocean Frontal analysis model Ocean wave analysis model Sea Surface Temperature analysis model Learning Objective Recognize the impact of grid point spacing on computer generated a
38. in the mid latitudes hows a 500 millibar 48 hour prog nosis Except for the chart identification and contour labeling these charts are very similar The winds temperature and height prognosis data fields are usually combined on a single chart for each of the various constant pressure surfaces Winds are represented with standard plots height contours isoheights by solid lines and temperature isotherms by dashed lines charts use a 5 C isotherm interval with the temperatures labeled in degrees Celsius The 850 millibar chart uses a 30 meter isoheight interval the 700 and 500 millibar charts use a 60 meter isoheight interval and the 400 300 and 200 millibar charts use a 120 meter Figure 4 2 5 850 millibar analysis 4 2 6 7 375 Y N nf 2370 oe ets ol 2 Thang is He PROG UI PRU 3 1508 T BEAR PROG 902715 JUL Ape Ep AR A 59M 36HR PROG VT OZ 15 L Ph Re ul a LAT i 2 N N r ag 2051 E Figure 4 2 6 500 millibar prognosis isoheight interval While the 500 millibar level is routinely available in 12 hour increments out to 120 hours and the other levels are routinely available in 12 hour increments out to 72 hours the charts transmitted on the Fleet Facsimile broadcasts are usually limited to the 24 and 48 hour forecasts Generally 4 2
39. libar level extrapolated downward The height of the tropopause is found at the point where the two lapse rates intersect This level averages out to be 700 feet below the observed tropopause A 5 year evaluation period of the above method also showed that on the average the level of maximum winds in the jet core is found 2 300 feet below derived tropopause heights The model incorporates a 3 000 foot constant to account for the 700 and 2 300 foot deviations This means a tropopause height chart actually represents the level of maximum winds The true tropopause height is 3 000 feet higher than indicated on the chart FREEZING LEVEL MODEL The freezing level model interpolates the freez ing level from the temperatures reported at the mandatory constant pressure levels Starting at 1 000 millibar the computer checks the tempera ture at each mandatory level until it encounters the first level with a temperature below O C The model uses this level and the one preceding it to interpolate the freezing level There are some problems associated with this linear interpolation process It does not account for the following 1 poor constant pressure height and or temperature analyses 2 inver sions or 3 multiple freezing levels Even with the above limitations interpolated heights are normally within 100 feet of observed values The freezing level chart is widely used in aviation forecasting It is used to outline areas of potential
40. nalyses and identify the parameters and the analysis technique used FLENUMOCEANCEN s surface analy sis model SURFACE ANALYSIS MODEL The FLENUMOCEANCEN surface analysis model produces hemispheric and regional analyses of sea level pressure wind and sea surface temperature on grids For example a hemispheric analysis is produced on a 63 by 63 grid and a regional analysis uses a 125 by 125 grid Grids Grids come in various shapes and sizes The grid point spacing for hemispheric products is equivalent to approximately 320 kilometers whereas that for regional products is equivalent to 20 to 80 kilometers The grids used in regional analysis are known as fine mesh grids All computer calculations are performed at the grid points and normally the closer the grid point spacing the more accurate the analysis depending on the accuracy of the input data Each grid point is assigned a value of the parameter being analyzed For example in a sea level pressure SLP analysis each grid point is assigned an SLP The value assigned to a grid point may be based on past history current observations gradient extrapolation and or any combination of these three variables This process is part of the analysis technique used by the model Fields By Information Blending The surface analysis model currently used by FLENUMOCEANCEN uses an analysis technique known as Fields by Information Blending FIB FIB has six component o
41. ntermediate isobars may be shown as dashed lines All isobars are labeled with two figures for tens and units of millibars Z Pressure centers are indicated by Hs for high pressure and Ls for low pressure with central pressure values given in two figures for tens and units of millibars Z Date and time of the analysis are printed in an identification block in the lower left and upper right on the Northern Hemisphere analysis corner of each chart Weather Depiction Analysis The weather depiction analysis is a computer plotted computer analyzed summary of aviation terminal conditions and is produced eight times a day every 3 hours starting at O100Z It is designed to be primarily a briefing tool to alert aviation interests to the location of critical and near critical operational minimums for the United States and surrounding land areas Figure 4 3 4 shows a typical example of this chart The following information is depicted on each chart Z Instrument Flight Rules IFR condition areas are enclosed by solid lines and are shaded These are areas with ceilings below 1 000 feet and or visibility below 3 statute miles Z Marginal Visual Flight Rules MVFR condition areas are surrounded by a solid line but are not shaded These are areas where the ceilings are between 1 000 and 3 000 feet and or the visibility is between 3 and 5 statute miles inclusive Table 4 3 1 Frontal Type Intensity and Character Codes 1152
42. perations as follows l First guess field preparation of initializa tion Assembly of new information Blending for the parameter 4 Computing the reliability field of the blended parameter 5 Reevaluation and lateral rejection 6 Reanalysis 2 3 FIRST GUESS The first guess is an estimate of what an analysis will look like without consider ing current data It is normally a blend of 1 the previous analysis extrapolated forward to analysis time 2 a prognostic chart verifying at analysis time 3 persistence from the previous analysis and 4 climatology The first guess provides continuity in data sparse areas and gives an estimate of the shape gradients curvature etc of the data field In data sparse areas the accuracy of a final analysis depends partly upon the first guess accuracy 4 1 2 The first guess field is also useful in keeping impossible observations from being used in the analysis ASSEMBLY OF NEW IN FORMATION In this step reports of the parameter being analyzed that is pressure wind etc are placed at their proper geographic positions on the grid These observations are then compared to the first guess values If an observed value differs from a first guess value by a pre set limit the observed value is termed impossible and is thrown out There is an inherent problem with the assembly step The majority of the oceans are data sparse When observations in an area are
43. phic map projections in a wide range of map scales The examples provided in the text are generally the larger scale map projections Sea Surface Temperature Analysis The sea surface temperature analysis shown in figure 4 2 8 15 typical of the low resolution 6 gt Taal Figure 4 2 8 Sea surface temperature analysis 4 2 9 product transmitted via the facsimile broad Sea Surface Temperature cast Solid lines are used to depict sea surface Anomaly Analysis temperature isotherms every 4 C A similar medium resolution chart is also transmitted The sea surface temperature anomaly chart that uses a 2 C isotherm interval Very small depicts areas that are warmer or cooler than the scale high resolution charts are available on dimatic normal for the month Areas endosed the NEDS that which use a 1 interval or with an isotherm that show a negative temperature less are colder than normal The example shown in 28 1272E i LE of Vf ct 2 Oe 48 41 25 ess eee AUS SN 9 9 81 0 6 47 iz 1594 50i 440 7 ag y Figure 4 2 9 Sea surface temperature anomaly analysis 1 122 10 san ba oort KAREN 40 SOuf 40 326 124 10V ME eow Figure 4 2 10 Significant wave height hemispheric analysis 4 2 10 figure 4 2 9 is a Mercator hemispheric p
44. phy Command and Fleet Aerographer s Mates Identify the major numerical prediction models used by the National Weather Service Identify parameters on the most frequently used National Weather Service facsimile charts Interpret commonly used National Weather Service bulletins NATIONAL WEATHER SERVICE CHARTS AND PRODUCTS The National Weather Service NWS head quartered in Suitland Maryland operates as a 4 3 1 OUTLINE General types of National Weather Service products Availability of NWS products to Naval Oceanography Command units Availability of NWS products to Fleet Aerographer s Mates Informational sources about NWS products availability and schedules Numerical prediction models used by the National Weather Service Parameters on NWS facsimile charts Surface analysis Weather depiction analysis Radar Summary analysis Upper air analysis Composite analysis 12 hour upper wind forecast 12 to 48 hour Boundary Layer wind forecast 12 to 48 hour surface weather forecast series NGM 12 to 48 hour forecast series MOS probability forecast Mid range surface forecast Mid range temperature forecast Interpretation of frequently used coded bulletins branch of the National Oceanic and Atmospheric Administration NOAA under the U S Depart ment of Commerce The National Weather Service computers at the National Meteorological Center NMC in Suitland are the focal point for meteorological data collection
45. pical portion of the example that several areas are surrounded by only 10 percent probabilit y contours These areas indicate that the computer has found only minor discontinuities A minor discontinuity maybe a pressure fall or a wind shear line indicating a tropical wave In the mid latitudes the lower probability contours may indicate a pressure ey N vio Y513 12 1111 9601102303 ZzUMCLASSIFIED 17 3 WRF cu SET 2 trough or a very weak non weather produci ng frontal position While you may infer frontal intensity weak moderate or strong from this chart you would need to compare this chart to previous charts to infer frontal type cold warm occluded and frontal character undergoing frontogenesis undergoing frontolysis or having no change Surface Weather Prognostic Charts Surface prognostic charts or forecasts of the surface pressure surface wind and frontal depiction are produced every 12 hours beginning at 0000Z Surface pressure prognoses are available out to 120 hours 5 days Figure 4 2 4 shows a typical surface wind and surfacepressure prog nosis Winds and pressure are depicted the same as on the analysis charts Frontal depiction prog nosis charts are produced to match the area and map projection of the surface prognosis charts This polar stereographic map projection example 4 2 4 is typical of most of the charts produ
46. produce a pressure analysis of the region equatorward of 20 and S The first guess wind analysis for mid latitudes is derived from the surface pressure analysis the first guess wind analysis for the tropics is obtained by blending the previous wind analysis with dimatology A global marine wind analysis is performed to blend the mid latitude and tropical wind fields together Optimum Interpolation Technique The FIB technique will be replaced in the near future by an Optimum Interpolation technique The OI technique is an objective analysis methodology widely used in meteorolog ical and oceanographic applications It differs from the FIB technique in that it is based upon the concept that the results of the interpolation process must contain the same statistical field properties that is time and space statistical structure of variability independent of the density of observations Learning Objective Name the FLENUM OCEANCEN model used to analyze upper air data and recognize why the program is run every 6 hours UPPER AIR ANALYSIS MODEL The upper air analysis model is a subset of the Navy Operational Global Atmospheric Prediction System NOGAPS Geopotential heights temperature and wind are analyzed for the mandatory levels 1 000 millibars to 100 millibars NOGAPS Model NOGAPS is the principal model system in FLENUMOCEANCEN s operational data runs which begin at 007 and 12Z It starts approximately 4 hour
47. rameters would provide the best analysis Salinity and biological parameters were not even considered because of the lack of synoptic data When all the testing was complete FLENUM OCEANCEN settled on surface and subsurface temperatures as the parameters it would use Like numerical atmospheric frontal analysis a GG operator is used to describe oceanic fronts It is applied to fine mesh SST analyses and to fine mesh subsurface temperature analyses The latter are obtained in the ocean thermal structure analyses performed by EOTS Frontal analyses based on fine mesh SST fields are considered very reliable Frontal analyses based on subsurface thermal fields are NOT con sidered to be overly reliable because subsurface data inputs are drastically sparse You should be aware of which field is used for input and know the locations of the observations used to make the field in order to evaluate the reliability of any ocean frontal analysis OCEAN WAVE ANALYSIS MODEL Ocean wave analysis is conducted numerically using the Global Spectral Ocean Wave Model GSOWM This model came into existence in 1985 and replaced the older Spectral Ocean Wave Model in all areas except the Mediterranean Sea GSOWM functions are performed on the standard FLENUMOCEANCEN 2 5 latitude by 2 5 longitude spherical grid in a global band extending from 77 5 N to 72 5 S GSOWM directional wave spectra is used to derive the following output fields signific
48. rojection that uses a 2 C contour interval Regional analyses are also available that use a 1 C isotherm interval Significant Wave Height Analysis and Prognosis The significant wave haght SIG WAVE HT analysis and prognosis charts are very useful for daily shipboard sea state forecasting heavy weather avoidance and Optimum Track Ship Routing Figure 4 2 10 shows a typical low resolution hemispheric analysis Figure 4 2 11 Rer shows a typical regional prognosis The hemispheric analysis uses a 6 foot wave height contour interval starting at 12 feet the regional analyses and forecasts use a 3 foot contour interval beginning at 3 feet The significant wave height charts do not specifically show wind wave heights or swell wave heights It shows computer calculations of the significant highest one third of the sea waves waves produced by the local winds based on the fetch and duration from the analyzed and forecast surface wind fields It will not indicate the swell waves which may at times be higher than the sea waves It also does not indicate a prevailing wave aie bey yk 3 Figure 4 2 11 Significant wave height regional prognosis 4 2 11 direction although this may be inferred by comparing the SIG WAVE HT charts to the corresponding surface wind charts the primary wave direction should be the same as the direction the wind is blowing towards Remember though that wind directions ar
49. s into a data run NOGAPS replaced the Primitive Equation PE model as FLENUMOCEANCEN s primary forecast model in 1982 NOGAPS was last updated in 1986 NOGAPS upper air subset is run every 6 hours even though radiosonde and rawinsonde observations are taken synoptically at 0000Z and 1200Z only By running the program every 6 hours off time observations can be induded in the run This permits the inclusion of satellite data and aircraft reports as well as off time buoy and ship reports This means that during any single analysis there can be as much as a 6 hour difference in observations The program carries the off time data forward to analysis time This process is referred to as data assimilation NOTE The 0600Z and 1800Z upper air analyses are used as a basis for the 1200Z and 0000Z data runs They are NOT transmitted to the Fleet In addition to the NOGAPS generated spherical upper air analyses FLENUMOCEAN CEN also produces global band upper air analyses and southern hemispheric polar stereographic upper air analyses Global Band Upper air Analysis Winds and temperatures are analyzed on a global band grid every 12 hours The grid is a Mercator projection true at 22 1 2 degrees latitude and extends from 40 S to 60 N The first guess field south of 22 N is based on persistence reverted to climatology This is primarily due to the sparseness of data over large portions of this region North of 22 N NOGAPS upper
50. spect of the frontal analysis model is its overall accuracy Large grid size and the possible inaccuracy of upper air temperature analyses over data sparse areas precludes frontal positions from being more accurate than 100 miles The program also has a few other weaknesses as follows Z It may indicate fronts in mountainous regions when no fronts exist Z t handles occlusions poorly because of the lack of thermal contrast across occluded fronts Z It handles fast moving cold fronts poorly because the major temperature contrast occurs well behind the front Z t produces false frontal indications in regions where fast forming strong inversions develop For all the above reasons CG frontal analyses should NOT be used as the final deter mination in positioning fronts We recommend that you use the CG analysis as a first guess or simply as a guide in your analysis procedure Y ou should analyze as many frontal placement parameters as possible before settling on your final frontal positions Learning Objective Recognize how FLENUMOCEANCEN models derive the heights of the tropopause and the freezing level TROPOPAUSE HEIGHT ANALYSIS MODEL The tropopause is defined by characteristic changes in the temperature lapse rate In computing the height of the tropopause the FLENUMOCEANCEN model combines the lapse rate between the 500 and 400 millibar levels extrapolated upward and the lapse rate between 150 and 100 mil
51. state Mixed Layer Depth Charts The mixed layer depth MLD analysis chart shown in figure 4 2 12 depicts the depth of the mixed layer in meters Contours are drawn on the hemispheric chart at 10 20 30 45 60 80 100 140 180 230 and 280 meters The deeper the mixed layer the larger the contour interval The MLD is the bottom of the uppermost layer of the ocean the Mixed Layer which because of mixing by waves and currents is usually fairly isothermal or shows only a slightly negative temperature gradient with depth The MLD is also considered the top of the second ocean layer the Main Thermocline where the temperature decreases rapidly with depth Because of the sharp decrease in the temperature gradient with depth at the MLD the MLD usually but not always is the point of maximum sound velocity in the upper 1 500 feet of the sea In the cases where the MLD is the point of maximum sound velocity it is also known as the Sonic Layer Depth SLD Figure 4 2 12 MLD analysis 4 2 12 Prognostic charts of the forecast change in the increasing or decreasing wave heights The MLD are available in addition to the analyses contours are in meters with a 4 meter interval Figure 4 2 13 shows a full hemisphere Northern Negative values indicate an increasing MLD the polar stereographic projection of the 24 hour MLD becomes deeper positive values indicate forecast changes in the MLD which are due to a decreasing MLD
52. synoptic analysts and forecasters The problem stems from distortion in the circulation patterns caused by the interaction of small scale and large scale features The classical example for instance occurs in the vertical the long wave patterns are distorted by short waves The distortion makes for subjective positioning of the long waves and the positions are usually inaccurate An inaccurate analysis then leads to inaccurate prognoses To overcome such subjective determinations the scale and separation model was developed The scale and separation model provides an objective measure of scale while retaining characteristic recognizable patterns It separates features of various size into separate parts For example it takes the 500 millibar field and separates it into a short wave field 500 millibar SD a long wave field 500 millibar SL a residual field 500 millibar SR and a planetary vortex field 500 millibar SV The model uses a smoothing process to separate each field For example if the small scale features SD are smoothed out of the total field Z a residual field SR remains The residual field contains the large scale disturbance features SL and the planetary vortex SV The SR field at 500 millibars is ideal for locating long wave troughs A more massive smoothing process continues on the residual SR field until only the planetary vortex remains The large scale disturbance pattern is obtained by subtracting
53. tems better than the other models which allow temperature changes due to advection The Barotropic model output should always be used in conjunction with other model outputs to serve as a comparison and guidance for only the barotropiclike systems It is good guidance for forecasting jet stream movement LFM Model Output Statistics LFM MOS Output Statistics MOS is a program that incorporates output from the LFMII model and compares this output with historical condi tions since 1969 for a region or station to produce a forecast for that region or station Different parameters are considered for the warm season April through September and the cool season October through March In some cases the model distinguishes differences for four seasons Output from the LFM MOS model is available in bulletin format out to 60 hours citing best chances for maximum and minimum temperatures and probabilities for different types of weather occurrence such as low ceilings fog and thunderstorms Output is also available as a computer worded forecast for a region or a specific location It is also available as graphic charts out to 48 hours these charts indicate various parameters for the United States such as probability of precipitation maximum and minimum temperatures surface winds and winds aloft and doud cover NGM Model Output Statistics NGM Perfect Prog Implemented in April 1987 the NGM Perfect Prog is very simil
54. the majority of the data induding the overseas data is provided by NWS It may be interesting to remember the next time you receive some local weather data aboard ship off the coast of Malaysia that the data actually traveled around the world from Malaysia to Switzerland to Suitland Maryland to Carswell AFB Texas to Hawaii to Guam and finally to your ship Although the NWS regional HF teletype broadcasts were discontinued several years ago the current operational and planned AFDIGS HF broadcasts should provide a valuable facsimile and teletype data source for our use AFDIGS actually has four digital graphics weather circuits CONDIGS for the continental United States PACDIGS for the Pacific HALDIGS for Central America and EURDIGS for Europe Until recently the only way to receive any of the AFDIGS products was to be connected to a dedicated land line satellite circuit Current plans for the USAF High Frequency Regional Broad cast HFRB System include multiple HF radio broadcast sites for all of the AF DIGS broadcasts AWS and NWS facsimile charts are transmitted on the upper sideband with AWS NWS and foreign data and bulletins being transmitted via radioteletype on the lower sideband of each frequency As of late 1989 the currently operational sites are Elmendorf AF B Alaska and Elkhorn Nebraska Six additional sites will be brought on line by the end of 1991 Anderson AF B Guam for the western and central Pacifi
55. the planetary vortex field from the residual field SL SR SV The smoothing 4 1 5 relationships in the order given above are Z SD SR and 58 5 51 Thus SV SR SLorZ SL SD SL SR SV or Z SV SD and SD Z SR or Z SV SL To be totally accurate the amount of smooth ing required to remove any one scale should vary depending on the time of year However the FLENUMOCEANCEN model employs only the October smoothing value so as not to disrupt component continuity This results in sL features being somewhat weaker than they should be in summer and the SD features being somewhat stronger The reverse is true in winter Learning Objective Recognize the parameter used in FLENUMOCEAN CEN s atmospheric frontal model and the strengths and weakness of the final product FRONTAL ANALYSIS MODEL The most desirable aspect of the FLENUM OCEANCEN frontal analysis model is its objec tivity The fact that mean potential temperature is the only parameter used to determine frontal positions makes it very objective Potential temperatures 8 are obtained by calculating the 1 000 to 700 millibar thickness field and converting the thickness to the mean potential temperature of the 1 000 to 700 millibar layer The program then computes the gradient of the mean potential temperature gradient GG A GG analysis accurately marks the division between two air masses having different thermal structures The least desirable a
56. the various source depths and receiver depths are depicted for each frequency 7 PHITARV VLAD Mode used with the VLAD sonobouy PHITAR propagation loss data is used by the requestor to plot propagation loss proploss curves and thereby determine expected passive acoustic ranges for the sonar systems of interest Because of the sensitivity of the information contained in the actual Acoustic Range Prediction products we cannot present meaningful examples of each product or provide a breakdown of the message format To properly interpret these products you should consult NAVOCEANCOM Environmental Tactical Support Products Manual SUMMARY In this lesson we have discussed a few of the most widely used products available from the U S Navy s Fleet Numerical Oceanography Center Many specialized computer produced products are available for your use that we have not even mentioned Y ou should take the time some quiet mid watch to look through APR User s Manual General Acoustic Conditions Depiction System Users Guide and if you have the required clearance through the NAVOCEANCOM En vironmental Tactical Support Products Manual to familiarize yourself with some of the other computer produced products available 4 2 16 UNIT 4 LESSON 3 NATIONAL WEATHER SERVICE CHARTS AND PRODUCTS OVERVIEW Identify the types of National Weather Service products and the routine methods used to distribute these products to Naval Oceanogra
57. ur AFDIGS circuits are issued as a message on a monthly basis Any DOD user of AFDIGS may be placed on distribution for the appropriate circuit schedule WEFAX schedules and frequendies are issued by NWS to selected users The Naval Polar Oceanography Center NPOC Suitland re issues these schedules and frequencies in their Satadlite Information Notes to naval units Frequendies for the foreign weather broad casts both facsimile and radioteletype RATT which may contain selected NWS products are contained in Sdected Worldwide Marine Weather Broadcasts DMA WWMARWEATHRBC and in AWSR Air Weather Service Regulation 100 1 Global Weather Intercepts You will find the AWS source a much better reference when researching foreign frequencies for shipboard and mobile team use Most domestic and foreign meteorological facsimile broadcasts transmit at some time during the day a detailed transmission schedule Information on the breakdown of many of the codes used in NWS and foreign weather bulletins and on some facsimile charts is contained in NAVAIR 50 1P 11 International Meteorological Codes 1984 edition one of your required publications Learning Objective Identify the major numerical prediction models used by the National Weather Service NUMERICAL PREDICTION MODELS USED BY NWS NWS currently uses several different numerical prediction models for different applica tions We will not go into any great detail at this level b
58. use with the Vertical Line Array DIFAR VLAD sonobouy ASRAP one way propagation loss informa tion is also applicable to shipboard passive sonar systems This product is primarily used by the VP squadrons Active ASRAP Products The Active ASRAP product was developed to support active airborne sonar systems This product supports the SSQ 47 SSQ 50 and SSQ 62 active sonobouys Range predictions are provided for different system modes and source receiver depth combinations which may be user specified The product is used by both VP and carrier based ASW squadrons as well as by surface combatants SHARPS Products SHARPS was developed to support shipboard and helicopter active sonar systems but now includes support for the passive mode as well This product may be fully tailored using specified sonar parameters for individual ships The product 4 2 15 displays a 50 percent probability of detection range as a function of sonar mode ship s speed and transmission path direct convergence zone and bottom bounce Estimated passive and active counter detection ranges are also provided PHITAR Products PHITAR primarily provides propagation loss data to submarines in a communications efficient form although it is also used by air and surface ASW squadrons It is available in three modes 2 PHITAR Receiver Mode the various frequencies and source depths are depicted for each receiver depth Z PHITARF Frequency mode
59. ut in 1 amp you will learn the strengths and weaknesses of each model Limited Fine Mesh Model II The Limited Fine Mesh Model 11 LFMII is still used for many 48 hour forecasts These are called short range forecasts Basically it forecasts seven layers of the atmosphere a planetary boundary layer 50 millibars about 1 500 feet above the surface three evenly spaced layers in the troposphere including a layer at the tropopause level and three evenly spaced layers in the stratosphere with the top layer at 50 millibars Sed figure 4 3 1 for a diagram of the layer structure of the model Forecasts at each layer are done on a grid with grid points about 116 kilometers apart at 45 latitude Nested Grid Model Since late 1985 the Nested Grid Model NGM has also been run for the North American continent in addition to the LFM The NGM is part of the NWS Regional Area Forecast System RAFS plan to improve the accuracy of numerical forecasts for the United States It uses 16 layers in its calculations more than twice as many as the LFM and a series of 3 nested grids The model makes calculations for the entire Northern Hemisphere on its coarsest most widely spaced grid points grid grid A Grid B is a finer polar stereographic grid it generally covers North America much of the Pacific some of the Atlantic and the polar region Grid C is the smallest and finest mesh grid it covers the eastern Pacific and

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