Product User Manual for the "Air Mass Analysis" product
Contents
1. 5 need to be taken into account A negative pseudo curvature vorticity is a natural further prerequisite for eligibility Then a ridge of the function is tracked by e repeated determination of the direction of smallest descent of the N function starting from a local minimum 2 2 4 Gradient zone product algorithm outline Main criterion for indicated gradient zone sufficiently extended zone of gradient above an empirical threshold either the gradient s x component or y component has to have the same sign all over the indicated zone otherwise two gradient zones would be joined which for geometrical reasons are unlikely to represent the same prefrontal region The product is cleaned in such a manner that gradient zone markers are withdrawn in regions where the SAFNWC MSG cloud mask reports clouds in those areas the product shows pixel values of an IR channel Note that the large scale check on the gradient zone comes first i e due to cloud masking some small patches of indicated gradient may appear in the final product 2 3 DESCRIPTION OF AIR MASS ANALYSIS AMA OUTPUTS This product consists of several sub products with different output format 1 The air mass classification product AMA CL provides air mass designations at pixel resolution The product format is HDF5 From v2008 on the gradient zone of the NWP equivalent potential temperature field product is an image like product packed into the same Co2. Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 WA Page 1 24 NWC SAF ZAMG Product User Manual for the Air Mass Analysis product AMA PGE12 v2 2 SAF NWC CDOP ZAMG SCI PUM 12 Issue 2 Rev 2 15 February 2012 Applicable to SAFNWC MSG version 2012 The EUMETSAT Network of Satellite Application Facilities Support to Nowcasting and Very Short Range Forecasting Prepared by ZAMG Code SAF NWC CDOP ZAMG SCI PUM 12 Issue 2 2 Date 15 February 2012 Product User Manual for the Air Mass Analysis product PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 VA 2 24 NWC SAF ZAMG REPORT SIGNATURE TABLE Prepared by ZAMG 15 February 2012 Reviewed by ZAMG 15 February 2012 Pilar Fernandez Authorised by SAFNWC Project 15 February 2012 Manager Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 Page 3 24 D NWC SAF ZAMG DOCUMENT CHANGE RECORD CHANGES 2 2 2 precursor documents on 12 most notably Software User Manual for the SAFNWC MSG 2 0 16 September 2007 Initial version content derived from various Scientific part for the 12 2
3. 440000 KELEM 160000 amp JBPW 32 KVALS 4096000 DIMENSION KSUP JSUP KSECO JSECO KSEC1 JSEC1 DIMENSION KSEC2 JSEC2 KSEC3 JSEC3 KSEC4 JSEC4 INTEGER DIMENSION JBUEL KBUFF REAL 8 DIMENSION KVALS VALUES Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 Page 22 24 REAL DIMENSION 200000 CONTOURX CONTOURY CONTOURZ CHARACTER LEN 64 DIMENSION KELEM CNAMES CHARACTER LEN 24 DIMENSION KELEM CUNITS CHARACTER LEN 80 DIMENSION KELEM CVALS OPEN MAGICS DEFINE GRAPHICAL DEVICE AND FIX GEOGRAPHICAL AREA CALL POPEN CALL OUTPUT_FORMAT PS CALL OUTPUT_NAME PGE12a CALL PSETC PAGE_ID_LINE OFF CALL PSETC SUBPAGE_MAP_PROJECTION POLAR_STEREOGRAPHIC CALL SUBPAGE_MAP_AREA_DEFINITION CORNERS CALL SUBPAGE_MAP_VERTICAL_LONGITUDE 0 0 CALL PSETR SUBPAGE_LOWER_LEFT_LONGITUDE 29 5 CALL SUBPAGE_LOWER_LEFT_LATITUDE 22 6 CALL PSETR SUBPAGE_UPPER_RIGHT_LONGITUDE 73 1 CALL PSETR SUBPAGE_UPPER_RIGHT_LATITUDE 56 3 CALL PCOAST DECODE AND VISUALIZE THE THETA E RIDGE LINE PRODUCT IRET 0 CALL PBOPEN IUNIT SAFNWC_MSG2_AMA_201105120800_EUROPE____ T Ridge buf amp T IRET IF IRET NE 0 GOTO 201 CONTOURX
4. 999 NPOI_TOTAL 1 RLOOP DO I 1 200000 CALL PBBUFR IUNIT KBUFF JBYTE KBUFL IRET IF IRET 1 EXIT RLOOP done with file KBUFL KBUFL 4 1 KEL KELEM CALL BUFREX KBUFL KBUFF KSUP KSEC0 KSEC1 KSEC2 KSEC3 KSEC4 amp KEL CNAMES CUNITS KVALS VALUES CVALS KERR IF KERR NE 0 THEN WRITE 6 ERROR DURING DECODING GOTO 201 END IF NPOI INT VALUES 1 CONTOURY NPOITOTAL NPOI_TOTAL NPOI 1 VALUES 2 2 NPOI 2 CONTOURX NPOITOTAL NPOI_TOTAL NPOI 1 VALUES 3 2 NPOI 1 2 NPOI_TOTAL NPOI_TOTAL NPOI 1 END DO RLOOP PLOT THE RIDGE LINES CALL PSETC POLYLINE_LINE_COLOUR GREEN CALL PSETI POLYLINE_LINE_THICKNESS 3 CALL PSET1R POLYLINE_INPUT_LONGITUDES CONTOURX 1 NPOITOTAL 1 NPOITOTAL CALL PSET1R POLYLINE_INPUT_LATITUDES CONTOURY 1 NPOI_TOTAL 1 NPOITOTAL CALL PSET1R POLYLINE_INPUT_VALUES CONTOURZ 1 NPOI_TOTAL 1 NPOILTOTAL CALL PLINE 201 CALL PBCLOSE IUNIT IRET DECODE AND VISUALIZE THE WV STRIPE PRODUCT Product User Manual for the Air Mass Analysis product AMA PGE12 v2 2 Code SAF NWC CDOP ZAMG SCI PUM 12 Issue 2 2 Date 15 February 2012 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 Page 23 24 SLOOP 203 IRET 0 CALL PBOPEN IUNIT SAFNWC_MSG2_AMA_201105120800_EUROPE____ WVstripe buf amp T IRET IF IRET NE 0 GOTO 203 CONTOURX 999 NPOI_TOTAL 1 DO I 1 200000 CALL PBBUFR IUNIT KBUFF JBYTE KBUFL IRET IF IRET 1 EXIT SLOOP done
5. The first five entries are straightforward to set see also section 2 3 The other two parameters define the filtering of the ridge line product From v2008 on this product takes the NWP GRIB file provided by the user in s AFNWC import NWP _ data as it is and analyzes ridge lines on the NWP grid Thereby LAM output became permissible as input on the other hand this means that the developers can no longer control the meaning of significant ridge lines in terms of length of the ridge line and curvature of the isolines Length and curvature are encoded in the BUFR telegrams see section 2 3 and the two entries in the model configuration enable the user after some experience with his her own NWP data to set the filtering parameters appropriately if wished so At delivery the configuration parameters are basically functionless just reflecting that a line should consist of two points and a ridge is not cyclonic Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 Page 18 24 D NWC SAF ZAMG 5 AIR MASS ANALYSIS AMA VALIDATION 5 1 SUMMARY OF AIR MASS ANALYSIS AMA VALIDATION RESULTS The air mass analysis products face some conceptual difficulties w r t to their validation described in more detail in the two AMA validation reports RD 1 and AD 5 In this sit
6. 1 23 February 2009 Update for the SAFNWC MSG release 2009 mainly on new quality flag 2 1 1 8 September 2009 updates Minor mainly editorial updates for the SAFNWC MSG release 2010 scientific 2011 No scientific updates 15 February 2012 24 Update for the SAFNWC MSG release 2012 3 5 5 21 October 2010 Minor updates for the SAFNWC MSG release 24 Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 dA Page 4 24 NWC SAF ZAMG Table of contents 1 TATROD UC 6 1 1 a neke a a n e a er nT Ere E res er EET 6 12 SUPE OP OTHER DOC MENTS nacho ee 6 1 3 SOFTWARE VERSION IDENTIFICATION 6 1 4 IMPROVEMENT FROM PREVIOUS VERSION ss 6 1 5 DEFINITIONS ACRONYMS AND 6 1 REE Ce vsetossdeoscascaazasseadantannessecasnasanncalscansasesasasceasososasceaccsnasaaatasstaactosatcaasenseaosasesasanasaeas 7 1 6 1 Applicable Toss ARGS 7 1 6 2 Reference 7 2 DESCRIPTION OF THE AIR MASS ANALYSIS 9 2 1 GOAL OF THE AIR MASS ANALYSIS AMA PRODUCTS ccsssscsessecseseeeeseeeesseeeseesensneeessaeeses 9 2 2 OUTLINE OF AIR MASS ANALYSIS AMA ALGORITHMS 0 9 8 2 1 Air mass classification alg
7. 2 Date 15 February 2012 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 Page 19 24 6 EXAMPLES OF AIR MASS ANALYSIS AMA VISUALISATION Figure 1 shows the visualization of the BUFR products WV stripes and ridge lines of equivalent potential temperature Figure 2 gives an example how the air mass classification product may be presented to the user and Figure 3 provides a glance on a gradient zone output Sat 11088 2007 11 18 08 45 Figure 1 Ridge line detection for equivalent potential temperature field ECMWF forecast data the green lines indicate the positions of the automatically detected ridge axes Magenta isolines encircle the WV dark stripes that are identified by the respective part of the SAFNWC AMA package Case 16 November 2007 0845 UTC Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 Page 20 24 NWC SAF ZAMG 201106210845 Figure 2 Example display of the SAFNWC air mass classification product Case of 17 February 2012 1130 UTC Prevailing on the display is tropical continental and polar maritime air see attached colour legend optional stability inclusion was turned off Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2
8. PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 Page 16 24 NWC SAF ZAMG 4 INPUTS AND CONFIGURABLE PARAMETERS FOR AIR MASS ANALYSIS AMA 4 1 LIST OF INPUTS 4 1 1 Air mass classification product e SEVIRI IR imagery channels 7 3 and 13 4 e NWP information temperature und humidity information in various levels in DATABUF format as preprocessed by the SAFNWC MSG application SAFNWC MSG product Cloud mask which is the output of PGE01 of the SAFNWC MSG e SAFNWC MSG product Cloud top temperature and height which is the output of PGE03 of the SAFNWC MSG e Optionally Lifted Index imagery SPhR LI which is output of PGE13 of the SAFNWC MSG 4 1 2 WV dark stripe product e SEVIRI WV image channel 6 2 4 1 3 Ridge line product ECMWF NWP GRIB data temperature und humidity information in 850hPa 4 1 4 Gradient zone of equivalent potential temperature product ECMWF NWP data temperature und humidity information in 850hPa in DATABUF format as preprocessed by the SAFNWC MSG application SEVIRI IR imagery channel 13 4 SAFNWC MSG product Cloud mask which is the output of PGEO1 of the SAFNWC MSG 4 2 CONFIGURABLE PARAMETERS FOR AIR MASS ANALYSIS AMA The configurable parameters can be found in the model configuration file for the PGE12 which is separated into two parts The first section contains three parameters that can be set by the user Then
9. Product_id 6 Name of sub product variable Name of the sub product coded in the numberof BUFR file One of the following char WVstripe T Ridge Field Separator Separator for extension 1 char S Extension Extension of the product name 3 char buf to indicate the type of data Table 3 File name components of AMA BUFR output The template of the BUFR files is as follows 101000 SPECIFICATION OF THE REPLICATION 031002 EXTENDED DELAYED DESCRIPTOR REPLICATION FACTOR 301023 expands to 005002 LATITUDE COARSE ACCURACY Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 WA Page 13 24 NWC SAF ZAMG 006002 LONGITUDE COARSE ACCURACY 011021 RELATIVE VORTICITY The output files contain as many BUFR records as there are identified black stripes or ridge lines respectively This entry appears only in the ridge line product The product derivation starts with the computation of a pseudo curvature vorticity which describes the curvature of the NWP 850 hPa equivalent potential temperature isolines The internal absolute value of this quantity at the starting point of the ridge line tracking a local maximum of anticyclonicity is provided It should be a measure how distinctive the pattern is and therefore can be exploited to filter weakly developed ridges via a user s
10. mass classification suspended either intended by the user or due to some problems seek additional log messages for further explanation A value of 8 is added if the pixel is one with high clouds 1 e cloud top height above 2000 m and the air mass classification hence was obtained purely by geometric algorithms Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 Page 12 24 NWC SAF ZAMG Even if the user opted for SPhR LI inclusion the classification cannot include stability information in all cloudy areas low and high as SPhR does not provide values there the AMA QUALITY parameter is increased by 16 in order to signal this in the output file if the stability product is missing as a whole for whatever reason 16 is added for all analysed pixels The gradient zone product has 128 different count values with the following meaning 10 _ cloudfree no gradient zone identified cloudfree gradient zone identified cloudy information on gradient zone not relevant since only of significance in prefrontal areas IR greyscale image shown instead taken from the 13 4 micron channel Additionally the whole field might be filled with value 255 signalling that the entire gradient zone has been suspended either intended by the user or due to some problems seek additiona
11. the input and output data format for the SAFNWC MSG software 1 3 SOFTWARE VERSION IDENTIFICATION This document describes the products obtained from the PGE12 version included in the 2011 SAFNWC MSG software package delivery 1 4 IMPROVEMENT FROM PREVIOUS VERSION Rather than the previously used global regression PGE12 v2 2 employs a locally adaptive scheme to deduce air mass classification from reference points Provides air mass classification also over cloudy areas 1 5 DEFINITIONS ACRONYMS AND ABBREVIATIONS AMA Air Mass Analysis cfm PGE12 model configuration file nominally at SAFNWC config safnwe_pge1l2 cfm ECMWF European Centre for Medium range Weather Forecasts EUMETSAT European Organisation for the Exploitation of Meteorological Satellites GEOS Geostationary Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 VA Page 7 24 NWC SAF ZAMG HDF Hierarchical data Format HRIT High Rate Information Transmission IR Infrared LAM Limited Area Model LI Lifted Index MSG Meteosat Second Generation NWP Numerical Weather Prediction PGE Product Generation Element QC Quality Control SAF Satellite Application Facility SAFNWC SAF to support NoWCasting and Very Short Range Forecasting SAI Stability Analysis Imagery SEVIRI Spinning Enhanced Visible amp Infrared Imager SPh
12. to equatorial are numerically translated to values of a fractional air mass code hereafter FAMC from 1 0 to 4 0 and the FAMC at the considered pixel is obtained via weighted interpolation in the variables e WV7 3 brightness temperature e longitude and latitude The permissibility of clouds up to a height threshold of 2000 m derives from the use of the WV7 3 channel whose signal is not contaminated by low clouds Finally a series of purely geometrical methods is applied to fill the not yet classified areas including those with high clouds with the most probable airmass classification a neighbourhood inspection searching for a majority decision from surrounding already classified pixels followed by gap filling which determines the size of gaps in horizontal and vertical direction respectively and assigns the pixels along those lines in a 50 50 split to the adjacent classifications Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 Page 10 24 D Kal NWC SAF ZAMG After some releases based on the NWCSAF product total precipitable water TPW v2008 switched over to a NWP derived TPW TPW thresholds between continental and maritime air masses are dependent on the numerical values of the functions obtained in the regressions For perfectly arctic polar tropica
13. with file KBUFL KBUFL 4 1 KEL KELEM CALL BUFREX KBUFL KBUFF KSUP KSECO KSEC1 KSEC2 KSEC3 KSEC4 amp KEL CNAMES CUNITS KVALS VALUES CVALS KERR IF KERR NE 0 THEN WRITE 6 ERROR DURING DECODING GOTO 203 END IF NPOI INT VALUES 1 CONTOURY NPOI_TOTAL NPOI_TOTAL NPOI 1 VALUES 2 2 NPOI 2 CONTOURX NPOLTOTAL NPOITOTAL NPOI 1 VALUES 3 2 NPOI 1 2 NPOI_TOTAL NPOI_TOTAL NPOI 1 END DO SLOOP PLOT THE BLACK STRIPE CONTOURS CALL PSETC POLYLINE_LINE_COLOUR MAGENTA CALL PSET1R POLYLINE_INPUT_LONGITUDES CONTOURX 1 NPOI_TOTAL 1 NPOITOTAL CALL PSET1R POLYLINE_INPUT_LATITUDES CONTOURY 1 NPOI_TOTAL 1 NPOITOTAL CALL PSET1R POLYLINE_INPUT_VALUES CONTOURZ NPOITOTAL CALL PLINE CONTINUE CALL PBCLOSE IUNIT IRET CALL PCLOSE END Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 Page 24 24 D Kal NWC SAF ZAMG 7 REFERENCES Bader M J Forbes G S Grant J R Lilley R B E and Waters A J Eds 1995 Images in weather forecasting Cambridge University Press Cambridge Carlson T N 1991 Mid latitude weather systems Routledge London Jann A 2002 Use of a simple pattern recognition approach for the detection of ridge lines and stripes Meteorol Appl 9 357 365 Martin F Elizaga F and Riosalido R
14. 1999 The mushroom configuration in water vapour imagery and operational applications Meteorol Appl 6 143 154 ZAMG 2005 Manual of synoptic satellite meteorology Conceptual models CD ROM version 6 0 available from ZAMG and online on http www zamg ac at docu Manual start htm
15. 2 Date 15 February 2012 Page 21 24 NWC SAF ZAMG Figure 3 Example display of the SAFNWC gradient zone product as seen in the HDF View software Case of 19 June 2007 1630 UTC gradient zone painted red cloudy pixels plotted in greyscale For convenience the source code of a FORTRAN 90 program that draws similar graphics as the one in Figure 1 is included below Users are probably most interested in the sections on BUFR decoding hence these parts are highlighted by boldface printing The BUFRDC software freely available from ECMWF is used here subroutines PROPEN PBBUFR BUFREX PBCLOSE note that the BUFR decoding sections are virtually identical for the two sub products The other parts of the program mainly contain commands to accomplish the graphics output by the MAGICS package which in principle is able to digest BUFR input directly this functionality is however not exploited here in order to also support users of other visualization software THIS IS DEMO BUFR DECODING ROUTINE FOR LONGITUDE LATITUDE INFORMATION SUBMITTED BY SAFNWC AMA ROUTINES AUTHOR ALEXANDER JANN ZAMG VIENNA AUSTRIA CREATION DATE 12 05 2011 THIS IS INTENDED REPRESENT USEFUL SUPPORT TO USERS OF THE SAFNWC MSG SOFTWARE PACKAGE BUT COMES WITHOUT WARRANTY OF ANY KIND PROGRAM SAFNWC_AMA_BUFR JSUP 9 JSECO 3 JSEC1 40 JSEC2 4096 JSEC3 4 amp JSEC4 2 JELEM 160000 JBUFL 300000
16. OP ZAMG SCI PUM 12_ v2 2 VA Page 8 24 NWC SAF ZAMG amendments to or revisions of any of these publications do not apply For undated references the latest edition of the document referred to applies Latest documentation can be found at the SAFNWC Help Desk at http www nwcsaf org RD 1 Scientific report on Validation and Tuning of SAF NWC IOP ZAMG SCI VAL 1 1 0 19 08 05 MSG PGE12 RD 2 Table 2 List of Referenced Documents Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 Page 9 24 NWC SAF ZAMG 2 DESCRIPTION OF THE AIR MASS ANALYSIS AMA PRODUCTS 2 1 GOAL OF THE AIR MASS ANALYSIS AMA PRODUCTS PGE12 of the SAFNWC MSG provides several products considered useful for air mass analysis Well established concepts from literature were taken and implemented adapted for a use with SEVIRI imagery supplemented where necessary by NWP products A rather classical classification of air masses as function of total precipitable water and temperature derived from satellite data Tongues of equivalent potential temperature indicate protruding warm and moist air in which severe local convection is most likely to occur Carlson 1991 Bader et al 1995 ZAMG 2005 Therefore an objective determination of the ridge lines of the equivalent pote
17. R SEVIRI Physical Retrieval SUM Software User Manual TPW Total Precipitable Water WV Water Vapour 1 6 REFERENCES 1 6 1 Applicable Documents For dated references subsequent amendments to or revisions of any of these publications do not apply For undated references the latest edition of the document referred to applies Latest documentation can be found at the SAFNWC Help Desk at http www nwcsaf org AD 1 Interface Control Document for the SAF NWC CDOP INM SW ICD 1 External and Internal Interfaces of the SAFNWC MSG SAFNWC MSG Output Products Format SAF NWC CDOP INM SW ICD 3 Definition Software User Manual for the SAF NWC CDOP INM SW SUM 2 SAFNWC MSG application Algorithm Theoretical Basis Document for SAF NWC CDOP ZAMG SCI ATBD 12 the Air Mass Analysis product AMA PGE12 Validation Report for Air Mass Analysis SAF NWC CDOP ZAMG SCI VR 3 23 02 09 AMA PGE12 v2 1 Validation Report for Air Mass Analysis SAF NWC CDOP ZAMG SCI VR 5 1 23 11 11 AMA PGE12 v2 2 Table 1 List of Applicable Documents 1 6 2 Reference Documents The reference documents contain useful information related to the subject of the project This reference document complements the applicable documents For dated references subsequent Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CD
18. analysis of the local pattern It is therefore in principle possible even though the robustness for the common 512x512 pixel region has been verified that users select a too small analysis region Note that the flexibility on the region was introduced in v2008 in response to an understandable user request not on scientific grounds before that PGE12 used a large region covering all of Europe and substantial parts of the Atlantic Ocean With the tuning process being mainly done on subjective reasoning a certain risk of differing perception among different individuals cannot be ruled out Most sub products of PGE12 are based on the objective recognition of certain patterns that MAY indicate imminent convective activity None of these features is by itself a trigger of convective activity In fact there is no doubt that in the majority of cases or over most of the extension of such a phenomenon no severe weather is found Consequently they have always to be considered in conjunction with other relevant meteorological material not on their own Unfortunately with respect to setting the configurable parameters for ridge line detection section 4 2 no guidelines can be presented at the time being as it is hardly possible to cover all the different NWP input users may provide 2 NWC SAF D ZAMG Product User Manual for the Air Mass Analysis product AMA PGE12 v2 2 Code SAF NWC CDOP ZAMG SCI PUM 12 Issue 2
19. de SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 Page 11 24 NWC SAF ZAMG HDFS file product code 2 There is moreover a quantity AMA QUALITY which represents a quality flag implemented in a first version in 2009 and augmented in subsequent releases The number of air mass classes in the current version PGE12 of SAFNWC MSG release v2012 is 9 or 17 depending on whether the user turns the LI inclusion option off or on 8 placeholders for possible future use with the following coding if SPhR LI inclusion is not selected or the SPhR LI product is missing the lower numbers are selected and classes 13 to 24 do not appear Code Name 0 Unclassified 3 Arctic maritime stable 6 maritime stable O o 8 Tropical reserved for future use 9 Tropical maritime stable The parameter AMA QUALITY can assume values in the range 0 28 or 255 with the following meanings no continuity type QC possible because pixel not classified in at least one of the considered AMA CL fields no change in thermal category i e arctic polar tropical or equatorial and moisture category maritime vs continental between current and previous slot change in moisture category change in thermal category change in both moisture and thermal category Air
20. et keyword in the PGE12 model configuration file Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 dA Page 14 24 3 IMPLEMENTATION OF AIR MASS ANALYSIS AMA AMA is extracted by PGE12 of the SAFNWC MSG software package Detailed information on how to run this software package are available in the Software User Manual for the SAFNWC MSG application AD 3 The implementation of the PGE12 software follows the general implementation of components of the SAFNWC MSG software see the software part of the Software Users Manual of the SAFNWC MSG software for more details Basically the following steps are needed to run the PGE12 software Create or update configuration files system region model and run configuration files according to their format see the Interface Control Document ICD 1 for the External and Internal Interfaces of the SAFNWC MSG Files are situated in SAFNWC config In particular if the optional SPhR LI inclusion of 12 is desired set the entry INCORPORATE LI in the model configuration file SAFNWC config safnwe_pge12 cfm to YES default in the delivery is NO If only a sub selection of PGE12 products is required modify the relevant entries CLASSIFICATION PRODUCT WV_STRIPE PRODUCT RIDGE LINE PRODUCT GRADIENT ZONE PRODUCT in the model configura
21. igures Table T Listor Applicable Documeni 7 Table 2 Lastol Reterenced 8 Table 3 File name components of AMA BUFR 2 2 400 0 0 0 12 Figure 1 Ridge line detection for an equivalent potential temperature field ECMWF forecast data the green lines indicate the positions of the automatically detected ridge axes Magenta isolines encircle the WV dark stripes that are identified by the respective part of the SAFNWC AMA package Case 16 November 2007 0845 19 Figure 2 Example display of the SAFNWC air mass classification product Case of 17 February 2012 1130 UTC Prevailing on the display is tropical continental and polar maritime air see attached colour legend optional stability inclusion was turned Off 20 Figure 3 Example display of the SAFNWC gradient zone product as seen in the HDFView software Case of 19 June 2007 1630 UTC gradient zone painted red cloudy pixels plotted 21 Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 Page 6 24 D NWC SAF ZAMG 1 INTRODUCTION The Eumetsat Satellite Application Facilities SAF are dedicated centres of excellence for processing satellite data and form an integral part of the distributed EUMETSAT Application Grou
22. l and equatorial air the thresholds are respectively 0 48 1 13 2 66 and 6 25 cm In case that the user ordered inclusion of stability information a stable unstable attribute is assigned to each cloudfree pixel on the basis of simple SPhR LI thresholding 2 2 2 WV dark stripe detection algorithm outline The detection of dark stripes has the following principal steps 1 For each pixel it is checked whether the pixel is dark enough to be eligible i e whether it is darker than an empirical threshold brightness temperature has to be gt 40 5 2 For each candidate pixel it is verified that it is darker than most of its neighbours 3 The pixels passing the test undergo postprocessing a contouring algorithm is applied to encircle sufficiently extended conglomerates of such pixels 2 2 3 Ridge line product algorithm outline The SAFNWC AMA package determines the ridge line of the equivalent potential temperature derived from NWP forecast fields of temperature and humidity as follows e Computation of a pseudo curvature vorticity which describes the curvature of the NWP 850 hPa equivalent potential temperature isolines e For each point determination of number of neighbours N with higher values of pseudo curvature vorticity less anticyclonic neighbours Generally a point should have Ni gt 6 in order to be eligible However it can be shown and justified that occasionally also points with N 4 or
23. l log messages for further explanation The names of the output files adhere to SAFNWC MSG convention on HDF5 file naming 2 Additionally the coordinates of special lines are provided In order to provide the user with the utmost flexibility these lines are not super imposed on the image but are described in separate BUFR files the used BUFR edition is No 4 The employed naming convention mimics the SAFNWC system for BUFR format files to the extent possible it actually adds only the designation of the sub product a dark stripes in WV imagery WVstripe b ridge lines of the equivalent potential temperature field T Ridge Field Name Description Data Type Value Product_id 1 Identifier for SAFNWC 6 char SAFNWC Field Separator Separator 1 char underscore Product_id 2 Spacecraft identifier 4 char MSGi where i is an integer Field Separator Separator 1 char underscore Product_id 3 product name 4 char The PGE specific code Field Separator Separator 1 char underscore Product_id 4 Date time of acquisition of 12 char vyyyymmddhhmm SEVIRI image Field Separator Separator 1 char underscore Product_id 5 Name of processed region 12 char Taken from the entry under REGION in the region configuration file and padded by underscores where needed Field Separator Separator for extension 1 char S
24. nd Segment http www eumetsat int This documentation is provided by the SAF Support to Nowcasting and Very Short Range Forecasting SAFNWC The main objective of SAFNWC is to provide further develop and maintain software packages to be used for Nowcasting applications of operational meteorological satellite data by National Meteorological Services More information can be found at the SAFNWC webpage http www nwesaf org This document is applicable to the SAFNWC processing package for Meteosat satellites meteorological satellites SAFNWC MSG 1 1 SCOPE OF THE DOCUMENT This document is the Product User Manual for MSG Air Mass Analysis Products PGE12 This document contains practical information on the characteristics of the above mentioned products on their applicability and limitations 1 2 SCOPE OF OTHER DOCUMENTS The algorithms used to extract the MSG Air Mass Analysis Products PGE12 are detailed in an Algorithm Theoretical Basis Document AD 4 The latest validation of the algorithms used to extract the MSG Air Mass Analysis Products PGE12 is reported in a validation report AD 5 Instructions to install configure and execute the SAFNWC MSG software in order to extract the MSG Air Mass Analysis Products PGE12 are detailed in a Software User Manual AD 3 The Interface Control Documents AD 1 for the External and Internal Interfaces of the SAFNWC MSG and AD 2 MSG Output Product Format Definition detail
25. ntial temperature field is performed Indication of areas where there is high probability for the initiation of convection the areas at the leading edge of frontal cloud bands Therefore the pre frontal regions with high gradients of equivalent potential temperature are marked Motivating a sub product of objectively determined dark stripes in WV imagery dry air in the upper troposphere is another air mass type that is important in two respects 8 Dry air overrunning frontal zones is connected to the development of intensive convection at the leading parts of fronts ZAMG 2005 e The boundaries between wet and dry air boundaries between gray and black stripes in WV are preferred zones for initiation of convection Martin et al 1999 ZAMG 2005 2 2 OUTLINE OF AIR MASS ANALYSIS AMA ALGORITHMS 2 2 1 Air mass classification algorithm outline The implemented scheme is based on finding cloudfree reference pixels where IR13 4 almost certainly indicates the correct air mass type The motivation to use IR13 4 is that this is the only IR channel with a weighting function not peaking at the earth s surface thus mitigating land heating effects For each cloudfree pixel that has not been flagged as reference pixel or pixel with a cloud top height not exceeding 2000 m the closest reference pixels are sought in the surrounding If they all signal the same air mass the decision is easy If there are different air masses categories arctic
26. orithm outline ubannnnuabnnnnds 9 222 WY dark stripe detection algorithm outline 10 2 2 3 Ridge line algorithm outline 10 2 2 4 Gradient zone product algorithm outline 10 2 2 DESCRIPTION AIR MASS ANALYSIS AMA 8 1 10 3 IMPLEMENTATION OF AIR MASS ANALYSIS 40 2444 14 4 INPUTS AND CONFIGURABLE PARAMETERS FOR AIR MASS ANALYSIS 16 4 1 16 4 1 1 Air mass 16 4 1 2 16 4 1 3 Ridge line 16 4 1 4 Gradient zone of equivalent potential temperature product nsss 16 4 2 CONFIGURABLE PARAMETERS FOR AIR MASS ANALYSIS AMA 16 5 AIR MASS ANALYSIS AMA VALIDATION 4 42 18 5 1 SUMMARY OF AIR MASS ANALYSIS AMA VALIDATION 5 8 22 18 32 TYPICAL KNOWN PROBLEMS AND RECOMMENDATION FOR USE scccesssseceeeesneeeeessneeeesssneeeees 18 6 EXAMPLES OF AIR MASS ANALYSIS 0 19 7 REFERENCES 24 Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 WA Page 5 24 NWC SAF ZAMG List of Tables and F
27. starting with the entry PGE_ID the rest of the model configuration file is constituted by a section that should be touched only by the institute responsible for development maintenance of PGE12 which at present is ZAMG Keyword Possible Value s CLASSIFICATION PRODUCT Decide whether the air mass classification chain of characters YES or NO product is computed WV_STRIPE PRODUCT Decide whether the WV dark stripe chain of characters YES or NO product is computed Code SAF NWC CDOP ZAMG SCI PUM 12 Issue 2 2 Date 15 February 2012 Product User Manual for the Air Mass Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_v2 2 VA Page 17 24 NWC SAF ZAMG Keyword Description Type Possible Value s RIDGE_LINE PRODUCT Decode whether the ridge line product is computed GRADIENT ZONE PRODUCT Decide whether the gradient zone product is computed INCORPORATE LI Decide whether the NWCSAF SPhR LI chain of characters YES or NO product should be incorporated in the AMA air mass classification process RL MinLength The minimum length in terms of NWP integer all yet values lt 2 grid points a ridge line has to have in are set to 2 order to appear in the output internally RL MinAbsCurvature The minimum anticyclonic curvature an float all yet values lt 0 extremum has to have in order to be are set to 0 eligible as a starting point of a ridge line internally tracking
28. supplementary files are available SAFNWC src bufr_000360 bufrtables B0000000000098002001 TXT b SAFNWC src bufr_000360 bufrtables D0000000000098002001 TXT SAFNWC import Aux_data Topo_ 000 00 dat for METEOSAT 8 _ 009 50 dat These files are not included in the PGE12 distribution because they are packed into other libraries also delivered with SAFNWC MSG The listed files should be available after Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product AMA PGE12 v2 2 File SAF NWC CDOP ZAMG SCI PUM 12_ v2 2 Page 15 24 unpacking the full SAFNWC MSG SW package as described in the relevant documentation Then the processing of PGE12 is automatically monitored by the task manager see the Software Users Manual for the Task Manager of the SAFNWC MSG software Submitting PGE12 in stand alone mode not using the task manager Ensure that all required input data are available in their respective directories and that pre requirements listed under items 1 9 are fulfilled PGE12 can be called as follows from the directory where it is situated PGE12 YYYYMMDDhhmm region configuration file model configuration file Example PGE12 201103281145 myregion cfg safnwc_pgel2 cfm Code SAF NWC CDOP ZAMG SCI PUM 12 Product User Manual for the Air Mass Issue 2 2 Date 15 February 2012 Analysis product
29. tion files accordingly default in the delivery is YES i e all products are ordered change to NO if a certain sub product shall be suspended Algorithm configuration files are situated in the directory SAFNWC import Aux_data PGE12 These PGE12 input files are provided with the software package installed together with it and are not foreseen for modification by users The cloud mask CMa input which is the output of PGEO1 of the SAFNWC MSG matching slot and region has to be made available the directory SAFNWC export PGE01 The cloud top temperature and height input which is the output of of the SAFNWC MSG matching slot and region has to be made available in the directory SAFNWC export PGE03 Provided the user requested the inclusion of optional stability analysis imagery SPhR LI input which is an output of PGE13 of the SAFNWC MSG SPhR data matching slot and region have to be made available in the directory SAFNWC export PGE 13 For producing the products based on NWP data the reprocessed NWP data have to be available in the DATABUF directory SAFNWC tmp Ensure that the SEVIRI image file in HRIT format mandatory input is available in the directory SAFNWC import SEVIRI data Make sure that the environment variable SAFNWC is set The environment variable BUFR_TABLES need also be set as SAFNWC src bufr_000360 bufrtables Make sure that the following
30. uation the issues of validation in AD 5 were subjective judgements on whether the indicated ridge lines stripes were analysed in a similar fashion as a trained meteorologist would do whether these analyses are stable in time whether the analyses are stable against changes in the region selected by a user In RD 1 moreover actually observed cases of convection were used as starting points and it was investigated whether these were somehow predictable from the AMA products Recently the air mass classification was judged against tropopauses derived from IASI and ATOVS level 2 profiles AD 5 Test 5 A slight change of algorithmic thresholds was proposed as aresult and these changes were implemented in v2009 The latest validation report AD 7 informs about adaptations that allow to derive air mass classifications in cloudy areas and on a global scale including the Southern Hemisphere In summary based on those mostly subjective evaluations the products of v2012 give no reason for serious concern The two sub products being judged as hardly acceptable in RD 1 namely air mass classification and gradient zone saw a complete refurbishment of their concepts so the criticism expressed in this document today no longer holds 5 2 TYPICAL KNOWN PROBLEMS AND RECOMMENDATION FOR USE Pattern recognition routines generally benefit from large analysis area the more one sees from the surrounding the more certain is the
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