PRODUCT USER MANUAL Offline UV (OUV) Products
Contents
1. Basis Document AD1 1 2 Acronyms ARS Aerosol Retrieval System Aerosol product ATBD Algorithm Theoretical Basis Document AVHRR Advanced Very High Resolution Radiometer CIE Commission Internationale de l Eclairage International Commission on Illumination DLR Deutsches Zentrum fiir Luft und Raumfahrt German Aerospace Center DNA Deoxyribonucleic acid EUMETCast EUMETSAT s broadcast system for environmental data EUMETSAT European Organisation for the Exploitation of Meteorological Satellites FMI Finnish Meteorological Institute GOME 2 Global Ozone Monitoring Experiment 2 GTS Global Telecommunications System HDF Hierarchial Data Format Internet International network Metop Meteorological Operational satellite programme NOAA National Oceanic and Atmospheric Administration NOP Near real time Ozone Profile product NRT Near real time NTO Near real time Total Ozone product NUV Near real time UV product 03M SAF Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring OOP Offline Ozone Profile product OTO Offline Total Ozone product OUV Offline UV product PUM Product User Manual UMARF Unified Meteorological Archiving and Retrieval Facility UV Ultraviolet radiation UVI UV Index WHO World Health Organization 1 3 References 1 3 1 Applicable Documents AD1 OUV Algorithm Theoretical Basis Document SAF O3M FMT ATBD 001 Issue 1 4 28 6 2013 AD2 O3M SAF Product Requirements Document SAF O3M FMI2. of the diurnal cycle Moreover the processing data flow can be kept relatively simple because both the Metop and NOAA AVHRR data are available through EUMETCast The aerosol optical depth is currently taken from a climatology RD6 and the surface albedo from the climatologies of Tanskanen RD7 and Herman et al RD9 relative dose rate 2 4 6 8 10 12 14 16 18 20 22 t h Figure 2 3 The diurnal cycle of UV dose rate clear sky case shown for clarity together with the sampling achieved by Metop and NOAA AVHRR measurements The sampling of the diurnal cycle is improved at high latitudes where the instrument swaths overlap for consecutive orbits REFERENCE SAF O3M FMI PUM 001 2 EUMETSAT O3MSAF ISSUE 15 DATE 28 6 2013 PAGE 9 16 3 Product quality 3 1 Expected Accuracy and Validation The target product accuracy is 20 against ground based UV measurements The surface UV prod uct is validated by a validation service This service also located at FMI performs two different validation activities Firstly online quality monitoring compares new products with a time series of all previously processed products to detect any degration in the product quality These online quality monitoring plots are available at http 03msaf fmi fi uv validation online guality html Secondly the UV product is fully validated against guality checked ground based measurements These results are provided as validation reports The latest validat
3. the O3M SAF project products and services http o3msaf fmi fi O3M SAF Helpdesk o3msaf fmi fi REFERENCE SAF O3M FMI PUM 001 EUMETSAT 2 03MSAF ISSUE 15 DATE 28 6 2013 PAGE 3 16 DOCUMENT STATUS SHEET Issue Date Modified items Reason for change 1 0 15 11 2006 Initial revision of the full document 1 1 04 05 2007 moved algorithm description and error analysis to a separate ATBD as re guired by EUMETSAT updated the file naming convention 1 2 04 04 2008 added error fields 1 3 12 02 2009 clarified the setting of quality flags in section 3 2 table 3 in section 5 1 2 tables 7 and 8 in section 5 1 4 1 4 20 05 2013 added vitamin D weighting products removed SCUP h weighting products introduced the homogenized cover page added the SAF introduction page renumbered tables and figures reformatted tables 1 5 28 06 2013 sect 1 2 added acronyms sect 1 3 2 corrected the HDFS link eg 2 2 corrected O gt O 3P table 2 1 swapped wavelength ranges of UVA and UVB p 6 a HDES file gt an HDES file p 9 corrected typos changed produced operatively gt operationally processed sending e mail gt sending an email sect 3 2 rephrased the list on quality flag usage REFERENCE SAF O3M FMI PUM 001 2 EUMETSAT O3MSAF ISSUE 1 5 DATE 28 6 2013 PAGE 4 16 Contents 1 INTRODUCTION 1 1 Purpose and scope lt s ss son kos a ee a ee 1 2 ACTONY
4. 1I16LE HST STD 132LE HST IEEE F32LE HST IEEE F64LE Fortran HST FORTRAN SI1 C HST C SI The file naming convention of the OUV product is depicted in figure 5 3 YYYYMMDDv01p00 HDF5 extension processor version minor processor version major day month year Figure 5 3 The structure of the OUV file name REFERENCE SAF O3M FMI PUM 001 EUMETSAT O3MSAF ISSUE 15 DATE 28 6 2013 PAGE 16 16 A Traceability of metadata to Eumetsat Data Centre parameters This appendix contains details related to the interface between the catalogue of the EUMETSAT Data Centre previously named as UMARF this acronym is used here for clarity and the FMI archive AD3 The metadata parameters AD4 which are applicable to the O3MSAF products are stored in the HDF5 file as attributes in the Metadata group table 5 1 The tracing of UMARF parameters to the attributes in the product file is shown in table A 1 below The attributes can only have values which are allowed by UMARF UMARE Short Name Table A 1 Traceability of metadata to UMARF parameters Attribute Name Notes ASTI SatelliteID GORT OrbitType LONS N A Start Orbit Number LONE N A End Orbit Number LLAS N A SubSatellitePointStartLat LLOS N A SubSatellitePointStartLon LLAE N A SubSatellitePointEndLat LLOE N A SubSatellitePointEndLon LSVT N A Ascending Node Crossing Date and Time OCSA N A Occultation Satellite ID TBC OC
5. 8 003 28 011 1997 REFERENCE SAF O3M FMI PUM 001 2 EUMETSAT O3MSAF ISSUE 15 DATE 28 6 2013 PAGE 7 16 2 Product overview The O3M SAF offline surface UV product is derived from the measurements of the operational polar orbiting Metop and NOAA satellites The product contains the most important guantities of the Sun s radiation that can be harmful to life and materials on the Earth These quantities include daily doses and maximum dose rates of integrated UV B and UV A radiation together with values obtained by different biological weighting functions the solar noon UV index RD1 and quality control flags In addition photolysis freguencies for photodissosiation of ozone and nitrogen dioxide are given for air quality applications The product is calculated in a 0 5 degree regular grid and stored in an HDFS5 file The contents of the product file are listed in section 5 An example of the daily erythemal dose product is shown in figure 2 1 below 0 0 0 8 1 6 24 3 2 4 0 48 56 64 7 2 8 0 Figure 2 1 An example product field Erythemal CIE daily dose kJ m2 on 12 May 2008 The global coverage is limited by the swath of GOME 2 instrument leaving stripes at low latitudes The polar night and large solar zenith angles limit the coverage at the winter pole The biological weighting functions also known as action spectra model responses of different bio logical entities to UV radiation The currently applied functions are p
6. IGHALB_CLEARSKY quality flag HighAlbedoClearSkyPatm float atm Limiting surface pressure for setting the QC_HIGHALB_CLEARSKY quality flag InhomogeneousSurfaceHeightLimit float m Limiting surface height deviation for setting the QC_INHOMG_SURFACE quality flag InhomogeneousSurfaceAlbedoLimit float none Limiting surface albedo deviation for setting the OC INHOMG SURFACE guality flag 5 1 3 GRID DESCRIPTION Group The grid parameters are stored as attributes of the cri pescrwrion group The attributes are given in the following table Table 5 3 GRID DESCRIPTION group contents Attribute name Data type Unit Description XNumCells int N A Number of grid cells in the X direction YNumCells int N A Number of grid cells in the Y direction XStartLon float degree Longitude of the centre of the first grid cell in the X direction Longitude ranges from 180 to 180 YStartLat float degree Latitude of the centre of the first gird cell in the Y direction Latitude ranges from 90 to 90 XStepDeg float degree Step increment between the grid cells in the X direction YStepDeg float degree Step increment between the grid cells in the Y direction 5 1 4 GRID PRODUCT Group The datasets in the cr rropucr group are given in the following table The daily doses daily maximum dose rates and their error estimates are stored for the following four different biological weightings erythemal Cie DNA damage Dna generalized plant response Plan
7. IO HCHO BrO H20 aerosols and surface ultraviolet radiation utilising the satellites of EUMETSAT The majority of the O3M SAF products are based on data from the GOME 2 spectrometer onboard MetOp A satellite Another important task of the O3M SAF is the research and development in radiative transfer modelling and inversion methods for obtaining long term high guality atmospheric composition products from the satellite measurements Product families e Nearreal time Total Column NTO 03 NO O3Tropo NOzTropo e Nearreal time Ozone Profile NOP e Nearreal time UV Index NUV e Offline Total Column OTO 03 NO2 OsTropo NO2Tropo SO BrO H20 HCHO OCIO e Offline Ozone Profile OOP e Offline Surface UV OUV e Aerosols ARS Product timeliness and dissemination Data products are divided in two categories depending on how quickly they are available to users Near real time products are available in less than three hours after measurement These products are disseminated via EUMETCast NTO NOP GTS NTO NOP or Internet NUV Offline products are available in two weeks from the measurement and they are archived at the O3M SAF archives in Finnish Meteorological Institute OOP OUV ARS and German Aerospace Center OTO Only products with pre operational or operational status are disseminated Up to date status of the products and ordering info is available on the O3M SAF website Information about
8. K j9 6 NO 296K relative response cross section em molec 2 gt 0 5 0 2 At 360 380 400 o 300 350 400 450 508 wavelength nm wavelength nm 5 280 300 320 Figure 2 2 Left the biological weighting functions CIE blue DNA green Plant red and vitamin D cyan Right cross sections solid line and quantum yields dotted line for ozone blue and NO red The key factors affecting the surface UV radiation are ozone clouds aerosols and surface albedo The total ozone is obtained from the O3M SAF near real time total column ozone product NTO This product is made by German Aerospace Center DLR and disseminated via the EUMETCast broadcasting system It is derived from the measurements of the GOME 2 instrument onboard Metop satellites The cloud optical depth is estimated from AVHRR channel 1 visible reflectances AVHRR is also onboard the Metop satellites The sampling of the diurnal cloud cycle is improved by using additional AVHRR data from the NOAA satellites available through the data exchange between EUMETSAT and NOAA Because Metop is on a morning orbit and NOAA satellite on the afternoon orbit at least two samples of the diurnal cycle can be obtained globally fig 2 3 More overpasses are available at high latitudes where the instrument swaths overlap for consecutive orbits This sampling scheme provides a sufficient compromise between the global coverage and sampling
9. LA N A Occultation Latitude TBC OCLO N A Occultation Longitude TBC OCTM N A Occultation Date and Time TBC AID InstrumentID SMOD N A InstrumentMode SSBT SensingStartTime SSST SensingEndTime ABID N A Spectral Band IDs GNSP N A Number of Spectral Bands RRCC N A ReceivingCentre RRBT N A Reception Start Date and Time RRST N A Ibid End Date and Time PPRC ProcessingCentre PPDT N A Processing Start Date and Time PPST ProcessingTime Processing End Date and Time GPLV ProcessingLevel AVBA BaseAlgorithmVersion AVPA ProductAlgorithm Version LMAP Map Projection LSCD N A SpatialCoverageModel APXS N A PixelSize SNIT ReferenceTime AENV N A SourceEnvironment GDMD Disposition Mode GPMD ProcessingMode APNM ProductType APNA N A Unique product identifier used in the O3M SAF archive not included in the product file provided to UMARF by archive software APPN ParentProducts APAS Added by Archive Product Actual Size not included in the product file provided to UMARF by archive software GNPO N A Native Pixel Order GNPF N A ProductFormatType GNFV ProductFormatVersion OCCV N A Cloud Coverage QQOV OverallQualityFlag QQAI QualityInformation QDRC DegradedRecordCount QDRP DegradedRecordPercentage QDLC MissingDataCount QDLP MissingDataPercentage AARF Added by Archive Archive Facility not included in the product file provided to UMARF by archive software UUDT N A Ingestion Date and Time GGT
10. MS 2 005 06 san se ahh KON Mitat aj aikaile Pe S hoat GS we de hw Sew 13 sREPCTENCES a s malicia o Rotat a pn okt a Sy aae ee ak ee oe Seg 8 1 3 1 Applicable Documents e 1 3 2 Reference Documents e 2 Product overview 3 Product quality 3 1 Expected Accuracy and Validation se 3 2 Quality flags e ss os ia Pog Ned KE PR AK PS Raoa ewe PS bees eae 3 3 Current Quality Issues cadrans eo nonna stadau 4 Processing archiving and dissemination 4 1 Processing and archiving 4 2 Product ordering lt lt aa ua sa a e da Naa eee aja 6 4 3 User services s sti aoc et eit a ere Ung M s How a Ge Ee edt Bn 5 Product file format Sil Pile structtre o eaa Saas ae ic ed oe a a a 5 1 1 METADATA Group 2 2 0 ken 5 1 2 PRODUCT SPECIFIC METADATA Group 5 1 3 GRID DESCRIPTION Group e 5 1 4 GRID PRODUCT Group hk e 52 Data Types ss eae kaa eo aamua ed a KAN PY Doe X HORN A 8 5 3 File naming convention ss skn A Traceability of metadata to Eumetsat Data Centre parameters 10 10 10 10 11 11 11 12 12 12 15 15 16 REFERENCE SAF O3M FMI PUM 001 2 EUMETSAT O3MSAF ISSUE 1 5 DATE 28 6 2013 PAGE 5 16 1 INTRODUCTION 1 1 Purpose and scope This document is the user manual of the O3M SAF Offline UV product OUV It includes the definition of the product format The algorithm and error analysis are described in a separate Algorithm Theoretical
11. Metop and NOAA satellites The output OUV product is stored in the FMI Archive from where it can be ordered via the Eumetsat Data Centre The processing data flow is depicted in figure 4 1 below e NTO As Hot Bird t EuretCast k uplink Metop AVHBR LAC JA EumetCast station at OLA AVAIN FAL recepton Usingen stationat FMI Figure 4 1 Overall processing data flow 4 2 Product ordering The product can be ordered from the Eumetsat Data Centre at http www eumetsat int Home Main DataAccess EUMETSATDataCentre index htm The product or der will be transmitted to the FMI Archive and the user will receive an e mail containing the instructions on how to download the data files 4 3 User services The helpdesk can be accessed through the O3M SAF web site at http o3msaf fmi fi or by sending an email to o3msaf fmi fi REFERENCE SAF O3M FMI PUM 001 2 EUMETSAT O3MSAF ISSUE 1 5 DATE 28 6 2013 PAGE 11 16 5 Product file format This section describes the HDF5 format RD8 of the offline UV product 5 1 File structure The data in the HDFS file is organized under four groups METADATA PRODUCT SPECIFIC METADATA GRID DESCRIPTION and cr rropvcr The file structure is shown in figure 5 1 The values in all groups are either copied from the input data or calculated by the processor The merapara group contains the parameters required by the METADATA PRODUCT SPECIFIC METADATA GRID DESCRIPTION GRID PRODUC
12. P GranuleType UDSP N A DispositionFlag UMARF internal
13. ProductType string Abbreviated name for the product type or rather product category O3MOUV ProductFormatVersion string Version number of the product format Issue of this User Manual document String lt 4 gt OverallOualityFlag string Overall guality flag for the product OK or NOK OualityInformation string Several miscellaneous guality indicators for the product String lt 511 gt DegradedRecordCount int Number of degraded product values Int DegradedRecordPercentage int Percentage of degraded product values Int 0 100 MissingDataCount int Number of missing product values Int MissingDataPercentage int Missing data percentage Int 0 100 GranuleType string Type description of the item DP MapProjection string Projection used by the product Geographic DispositionMode string Disposition mode applied for generation of the product O Operational P Pre operational 5 1 2 PRODUCT SPECIFIC METADATA Group The product specific metadata are listed in the following table Table 5 2 PRODUCT SPECIFIC METADATA group contents Attribute name Data type Unit Description LowSunNoonSza float degree Limiting solar noon zenith angle for setting the OC LOW SUN quality flag PolarNightNoonSza float degree Limiting solar noon zenith angle for setting the OC POLAR NIGHT quality flag ThickCloudsCod float none Limiting cloud optical depth for setting the QC_THICK_CLOUDS quality flag HighAlbedoClearSky float none Limiting surface albedo for setting the QC_H
14. REFERENCE SAF O3M FMI PUM 001 EUMETSAT 03MSAF ISSUE 15 DATE 28 6 2013 PAGE 1 16 The EUMETSAT Network of Satellite Application Facilities Ozone and Atmospheric Chemistry Monitoring PRODUCT USER MANUAL Offline UV OUV Products Prepared by Jukka Kujanp Finnish Meteorological Institute REFERENCE SAF O3M FMI PUM 001 EUMETSAT O3MSAF ISSUE 1 5 DATE 28 6 2013 PAGE 2 16 Introduction to EUMETSAT Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring O3M SAF Background The need for atmospheric chemistry monitoring was first realized when severe loss of stratospheric ozone was detected over the Polar Regions At the same time increased levels of ultraviolet radiation were ob served Ultraviolet radiation is known to be dangerous to humans and animals causing e g skin cancer cataract immune suppression and having harmful effects on agriculture forests and oceanic food chain In addition the global warming besides affecting the atmospheric chemistry also enhances the ozone depletion by cooling the stratosphere Combined these phenomena have immense effects on the whole planet Therefore monitoring the chemical composition of the atmosphere is a very important duty for EUMETSAT and the world wide scientific community Objectives The main objectives of the O3M SAF are to process archive validate and disseminate atmospheric com position products 03 NO SO OC
15. RQ PRD 001 Issue 1 3 16 5 2013 AD3 UMARF to SAFs ICD EUM UMA ICD 004 Issue 3 13 14 Feb 2007 AD4 UMARF SAF Metadata Definition EUM UMA TEN 030 Issue 1 7 09 Feb 2007 1 3 2 Reference Documents RD1 Global Solar UV Index A Practical Guide WHO 2002 ISBN 92 4 159007 6 Annex C http www who int uv publications en GlobalUVL pdf RD2 McKinlay A F and Diffey B L CIE Research Note 6 1 1987 RD3 Setlow R B Proc Nat Acad Sci USA 71 3363 3366 1974 RD4 Caldwell M M Solar UV Irradiation and the Growth and Development of Higher Plants pages 131 177 in Giese A G ed Photophysiology vol 6 Academic Press New York 1971 RDS CIE 2006 Action spectrum for the production of previtamin D3 in human skin Technical Report 174 International Commission on Illumination RD6 Kinne S 2007 Towards an observation tied AOD climatology presentation in AT2 Aerosol Workshop Bremen June 2007 REFERENCE SAF O3M FMI PUM 001 2 EUMETSAT O3MSAF ISSUE 15 DATE 28 6 2013 PAGE 6 16 RD7 Tanskanen A 2004 Lambertian surface albedo climatology at 360 nm from TOMS data using moving time window technique Proc XX Quadrennial Ozone Symposium 1 8 June Kos Greece pp 1159 1160 RD8 HDFS File Format Specification http www hdfgroup org HDF5 doc H5 format html RD9 Herman J R and E Celarier Earth surface reflectivity climatology at 340 380 nm from TOMS data J Geophys Res 102 2
16. T Figure 5 1 Structure of the HDFS file Eumetsat Data Centre while the propuct_speciric_metapata group is used for additional information specific to this product The product fields are stored in a regular longitude latitude grid The grid parameters are stored as attributes of the ari pescrrrion group whereas the product fields are stored as datasets in the crip_propucr group The x dimension of the grid is the longitude and the y dimension is the latitude The product fields are two dimensional arrays of floating point or integer data If a value for a grid cell cannot be calculated a fill value is written to the array Each array has five attributes Title Unit Fill Value ValidRangeMin and ValidRangeMax These are used to describe the contents of the array The organization of the data is illustrated in figure 5 2 XNumCells lt gt A S o po 3 V 5 E Z YSteppeg gt gt YStartLat 4 gt ij Longitude x XStartLon XStepDeg Figure 5 2 Organization of the product fields in the HDES file 5 1 1 METADATA Group The content of the merapara group is shown in the following table All parameters are stored as attributes of the group The allowed values for the parameters that are reguired by the Eumetsat Data Centre are consistent with the reguirements given in AD4 The allowed values given in italics mean any value of the given type e g string means that the attribute can contain any string within t
17. gle is larger than 70 degrees or if the surface albedo is high and therefore the corre sponding product values are flagged as of low quality The product values are also flagged if insufficient cloud data were available for the calculation of the diurnal integral Climatological values are currently used for surface albedo and aerosols The surface albedo clima tology fails during snow falling and melting periods which vary from year to year The aerosol clima tology on the other hand tends to underestimate the aerosol loading in the boundary layer especially during the summer time REFERENCE SAF O3M FMI PUM 001 2 EUMETSAT O3MSAF ISSUE 1 5 DATE 28 6 2013 PAGE 10 16 4 Processing archiving and dissemination 4 1 Processing and archiving The offline UV product is operationally processed with a maximum delay of 15 days between the satellite measurements and the dissemination to the users The actual delay depends on the operational computing environment and on possible delays in getting the input data from different sources The delay is typically three days The overall processing scheme is described below The input near real time total column ozone product NTO is produced by the German Aerospace Center DLR It is sent to the EUMETCast uplink station at Usingen Germany where it is broadcasted via telecommunication satellites Eurobird The NTO product is received at FMI together with input AVRRR level 1b products both from
18. he size limit REFERENCE SAF O3M FMI PUM 001 EUMETSAT O3MSAF ISSUE LS DATE 28 6 2013 PAGE 12 16 Table 5 1 METADATA group contents Attribute name Data type Description Allowed values SatelliteID string Platform identifier mission and spacecraft the product originated from M01 M02 M03 N15 N16 N17 N18 N19 etc OrbitType string Orbit type of the spacecraft indicating the coverage of the product LEO InstrumentID string Instrument which acquired the product GOME AVHR SensingStartTime string UTC date and time at acquisition start of the product YYYY MM DDThh mm dd SensingEndTime string UTC date and time at acquisition end of the product YY YY MM DDThh mm ss ddd ProcessingCentre string Centre that generated the data O3FMI ProcessingLevel string Processing level applied for generation of the product 03 ProcessingMode string Processing mode applied for generation of the product N Nominal B Backlogged R Reprocessed V Validation ProcessingTime string UTC date and time at processing end of the product YYYY MM DDThh mm ss ddd ReferenceTime string Time at which the product is defined to be valid Same value as ProcessingTime ProductAlgorithmVersion string Version of the algorithm that produced the product String lt 4 gt ParentProducts string A list of the name of the parent products upon which the product is based NTO AVHRR_level_1b BaseAlgorithmVersion string Version of the NTO product String lt 4 gt
19. int N A Ouality flags for the product See table 5 6 for interpretation of the bits Table 5 5 Attributes for the GRID PRODUCT group datasets Attribute name Title Unit FillValue ValidRangeMin ValidRangeMax string string same as the dataset same as the dataset same as the dataset Description Description of the dataset e g Solar noon UV index Unit of the values in the array e g second Number in the array if actual data value is missing Minimum allowed value for the data in the array Maximum allowed value for the data in the array EUMETSAT amp O3MSAF Bit W IP o n nan 10 11 12 13 15 16 19 20 23 24 27 28 31 REFERENCE SAF O3M FMI PUM 001 ISSUE 1 5 DATE 28 6 2013 PAGE 14 16 Table 5 6 Interpretation of the QualityField Flags have the value for on and 0 for off Name QC_MISSING QC_LOW_QUALITY QC_MEDIUM_QUALITY QC_INHOMOG_SURFACE OC_POLAR_NIGHT QC_LOW_SUN QC_OUTOFRANGE_INPUT QC_NO_CLOUD_DATA QC_POOR_DIURNAL_CLOUDS QC_THICK_CLOUDS QC_ALB_CLIM_IN_DYN_REG QC_LUT_OVERFLOW QC_HIGHALB_CLEARSKY reserved for future use QC_OZONE_SOURCE QC_NUM_AM_COT QC_NUM_PM_COT QC_NOON_TO_COT Description Data are missing At most low quality expected At most medium quality expected The surface UV varies too much within the grid cell because of surface inhomogenity The flag is set if surface height within the grid cell deviates from the mean value more
20. ion report is available on the O3M SAF web site at http o3msaf fmi fi uv validation latest report html 3 2 Quality flags Quality flags table 5 6 are set during the processing to indicate degraded product quality Figure 3 1 shows example plots of the quality flags These quality flags should be carefully examined when using the product In order to simplify basic quality control three summary flags table 5 7 have been designed QC_MISSING QC_LOW_QUALITY and oc MEDIUM OvaLITY The user is encouraged to use these summary flags as follows e If invalid data is to be filtered out apply oc missina This is also achieved by excluding fill values in the data e If low data quality is to be filtered out apply oc_Low_ouaLrry it contains ec_missinc e If medium quality data is to be filtered out apply oc menium it contains oc_Low_quatity 20070620 Polar Night Flag Figure 3 1 Example plots of the quality flags The red color indicates where the flag is on left The polar night flag is set when the solar zenith angle is larger than 88 degrees and right the low quality flag is set when it is larger than 70 degrees The low quality flag is also set for other conditions such as edges of ice sheets with inhomogeneous surface albedo and mountains with sloped surfaces 3 3 Current Quality Issues The estimation of effective cloud optical depth from the AVHRR reflectances becomes prone to errors if the solar zenith an
21. lotted in figure 2 2 left and a short description of their meaning is given in table 2 1 The photolysis frequencies Jo 1p and jo are the rate constants of the following two key reactions in the chemistry of the troposphere 1 Os hv X lt 320nm O D 0 101 P ci n 2 1 NO hv A lt 420nm gt NO OCP ano jvo N0 2 2 Absorption cross sections of ozone and nitrogen dioxide and the quantum yields of the two reactions are shown in figure 2 2 right The photolysis frequencies are currently given only at the surface level Table 2 1 Description of the biological weighting functions used in the OUV product Weighting function Ref Integration wavelength range nm Description CIE RD2 290 400 Measures the reddening of the skin due to sunburn Also known as the erythemal weight ing function Used for UV index DNA RD3 290 400 Measures the ability of UV irradiance to cause damage to unprotected DNA Plant RD4 290 400 Measures the generalized response of plants to UV irradiance UVB 290 315 Integrated UVB radiation UVA 315 400 Integrated UVA radiation Vitamin D RD5 290 330 production of previtamin D3 in human skin REFERENCE SAF O3M FMI PUM 001 EUMETSAT O3MSAF ISSUE 1 5 DATE 28 6 2013 PAGE 8 16 2 le 18 absorption cross sections and quantum yields 10 2 0 CIE o 0 298K 0 NO 298K a quantum yield O03 298
22. mate DailyMaxDoseRateCie float mW m2 Daily maximum dose rate CIE weighting DailyMaxDoseRateCieLow low dose rate estimate DailyMaxDoseRateCieHigh high dose rate estimate DailyMaxDoseRateDna float mW m2 Daily maximum dose rate DNA damage weighting DailyMaxDoseRateDnaLow low dose rate estimate DailyMaxDoseRateDnaHigh high dose rate estimate DailyMaxDoseRatePlant float mW m2 Daily maximum dose rate Plant response weighting DailyMaxDoseRatePlantLow low dose rate estimate DailyMaxDoseRatePlantHigh high dose rate estimate DailyMaxDoseRateVitd float mW m2 Daily maximum dose rate Vitamin D synthesis weighting DailyMaxDoseRate VitdLow low dose rate estimate DailyMaxDoseRateVitdHigh high dose rate estimate DailyMaxDoseRateUvb float mW m2 Daily maximum dose rate integrated UV B 290 315 nm DailyMaxDoseRateUvbLow low dose rate estimate DailyMaxDoseRateUvbHigh high dose rate estimate DailyMaxDoseRateUva float mW m2 Daily maximum dose rate integrated UV A 315 400 nm DailyMaxDoseRateUvaLow low dose rate estimate DailyMaxDoseRateUvaHigh high dose rate estimate DailyMaxJO1D float l s Daily maximum j O D DailyMaxJO1DLow low rate estimate DailyMaxJO1DLow high rate estimate DailyMaxJNO2 float l s Daily maximum j NO2 DailyMaxJNO2Low low rate estimate DailyMaxJNO2Low high rate estimate SolarNoonUvIndex float N A Solar noon UV index SolarNoonUvIndexLow low index estimate SolarNoonUvIndexHigh high index estimate OualityFlags
23. t and vitamin D Vitd together with integrated UV B 290 315 nm and UV A 315 400 nm radiation and the solar noon UV index In addition the daily maximum photolysis frequencies of O D formation and NO photodis sosiation are given Attributes attached to all datasets in this group are listed in table 5 5 The contents of the OualityFlags and the setting of the summary flags are listed in tables 5 6 and 5 7 EUMETSAT amp O3MSAF REFERENCE SAF O3M FMI PUM 001 ISSUE 1 5 DATE 28 6 2013 PAGE 13 16 Table 5 4 GRID_PRODUCT group contents Dataset name Data type Unit Description DailyDoseCie float J m2 Daily UV dose CIE weighting DailyDoseCieLow low dose estimate DailyDoseCieHigh high dose estimate DailyDoseDna float J m2 Daily UV dose DNA damage weighting DailyDoseDnaLow low dose estimate DailyDoseDnaHigh high dose estimate DailyDosePlant float J m2 Daily UV dose Plant response weighting DailyDosePlantLow low dose estimate DailyDosePlantHigh high dose estimate DailyDoseVitd float J m2 Daily UV dose Vitamin D synthesis weighting DailyDose VitdLow low dose estimate DailyDose VitdHigh high dose estimate DailyDoseUvb float J m2 Daily UV dose integrated UV B 290 315 nm DailyDoseUvbLow low dose estimate DailyDoseUvbHigh high dose estimate DailyDoseUva float J m2 Daily UV dose integrated UV A 315 400 nm DailyDoseUvaLow low dose estimate DailyDoseUvaHigh high dose esti
24. than the value InhomogeneousSurfaceHeightLimit given in the product specific metadata field surface albedo within the grid cell and its nearby neighbours deviates more than the value InhomogeneousSurfaceAlbedoLimit given in the product specific metadata field Polar night The solar zenith angle is larger than the value PolarNightNoonSza given in the product specific metadata field The Sun is too low for reliable radiative transfer modelling of surface UV The threshold solar zenith angle is given in the LowSunNoonSza attribute of the product specific metadata field Out of range input data was detected but the value could still be used in processing No cloud data were available Poor diurnal cloud coverage This flag is set when insufficient cloud data are available to cover the diurnal cloud cycle Thick clouds were observed This flag is set when optically thick clouds are observed during the day Saturation of the atmospheric reflectance as a function of the cloud optical depth prevents accurate estimation of the cloud optical depth and therefore the surface UV flux cannot be accurately determined The threshold cloud optical depth is given in the ThickCloudsCod attribute of the product specific metadata field Surface albedo climatology was used in a dynamic region where albedo varies with the snow and ice cover Look up table limits were exceeded and a value was extrapolated Clear sky was assumed if surface albedo was larger than the val
25. ue HighAlbedoClearSky and surface pressure was smaller than the value HighAlbedoClearSkyPatm given in the product specific metadata field 4 bits as an integer source of total column ozone data In the current version this is always 0 meaning GOME 2 total ozone NTO or OTO 4 bits as an integer number of cloud optical thickness observations in the morning value 15 indicating 15 or more observations 4 bits as an integer number of cloud optical thickness observations in the afternoon value 15 indicating 15 or more observations 4 bits as an integer minimum time in hours rounding towards zero between the solar noon and the nearest cloud optical thickness COT observation Table 5 7 Mapping of the quality flags to summary flags Summary flag Summary flag is on if any of these flags is on QC_MEDIUM_QUALITY QC_MISSING QC_POLAR_NIGHT QC_NO_CLOUD_DATA QC_LOW_QUALITY QC_MISSING QC_LOW_SUN QC_OUTOFRANGE_INPUT QC_LUT_OVERFLOW QC_LOW_QUALITY QC_POOR_DIURNAL_CLOUDS QC_HIGHALB_CLEARSKY QC_INHOMOG_SURFACE QC_THICK_CLOUDS QC_ALB_CLIM_IN_DYN_REG 2 EUMETSAT amp 03MSAF 5 2 Data Types REFERENCE SAF O3M FMI PUM 001 ISSUE 1 5 DATE 28 6 2013 PAGE 15 16 The data types to be used in the HDFS files are listed in the table 5 8 below Table 5 8 Data types for the HDES files Data type char short int int float double string 5 3 File naming convention HDFS predefined data type HST STD I8LE HST STD
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