Product User Manual for OUV
Contents
1. E OR desig eddie 4 2 PRODUCT OVERVIEW sumat esiti ee Ya nep ERES hapan DA NEAR NIE EE MESE K RITE 5 S PRODUCT QUALITY sassmassoassamuoaaess t ysi eesti 7 3 1 Expected Accuracy and Validation eese rennen nennen nennen 7 3 2 Quality Flags mi beer t aiii adierit lectos akan t rais 7 3 3 euasit T ostan oulan 8 4 PROCESSING ARCHIVING AND DISSEMINATION ee eeee eese sanoneen 9 4 1 Processing and Archiving i uoi rien iden eie ertet ete aan tiie E THE RE Te oe aee NSK inea 9 4 2 Product Ordering idein e Ree HR ERI RE DA EO Epi be PETERE Ee ERE Re ERG KALA KKUSEI DR Epp eid 9 4 3 USet SOEVICES Le cmn Hte ree era eie Qe ERE HL ei sp ettet el Ebr AEA SERRE eK ERA FPES TRE ba ved 9 5 PRODUCT FILE FORMAT iccectvemnssekeeekexis eite na aa neo ERE EUH L0 saaman FERE NUO a VERI REI lUe dde 10 NI File uunc 10 5 1 1 METADATA GEtOUD inre rient eee teri e IE ae ra Era RH ECA TREE PER Oke eere a kA ET ds 11 5 1 2 PRODUCT SPECIFIC METADATA Group esee ener 12 5 1 3 GRID DESCRIPTION Gro p tereti ctae reete ra ette idee EE ee Ceo Bree iian 12 5 L4 GRID PRODUCT Group vis tree rt eere recom aalkaa trees b ea 13 Di 2 Data Type e kasnaa 17 5 3 File naming conventlon iced ki kasan eei oL ven even et ED Ede eb dea Hte Late Pee se e akne i EST e kaaria 17 APPENDIX A TRACEABILITY OF MET2. name Offline UV Product REF SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 18 19 APPENDIX A TRACEABILITY OF METADATA TO UMARF PARAMETERS This appendix contains details related to the interface between the UMARF catalogue and the FMI archive The UMARF metadata parameters AD2 which are applicable to the O3MSAF products are stored in the HDF5 file as attributes in the Metadata group Table 2 The tracing of UMARF parameters to the attributes in the product file is shown in the following table The attributes can only have values which are allowed by UMARF UMARF Attribute Name Notes Short Name 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 OCLA N A Occultation Latitude TBC OCLO N A Occultation Longitude TBC OCTM N A Occultation Date and Time TBC AIID 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
3. of the O Operational product P Pre operational 5 1 2 PRODUCT SPECIFIC METADATA Group The product specific metadata are listed in the following table Table 3 PRODUCT SPECIFIC METADATA group contents Attribute name Data type Unit Description LowSunNoonSza float degree Limiting solar noon zenith angle for setting the QC LOW SUN quality flag PolarNightNoonSza float degree Limiting solar noon zenith angle for setting the QC 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 HIGHALB 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 QC INHOMG SURFACE quality flag 5 1 3 GRID DESCRIPTION Group The grid parameters are stored as attributes of the GRID DESCRIPTION group The attributes are given in the following table Offline UV Product per User Manual SAF O3M FMI PUM 001 ISSUE 1 3 DATE 12 02 2009 PAGE 13 19 Table 4 GRID_DESCRIPTION group contents Attribute name Dat
4. 131 177 in Giese A G ed Photophysiology vol 6 Academic Press RD5 Gruijl F R and Van der Leun J C Health Phys 67 4 319 325 1994 RD6 Kinne S 2007 Towards an observation tied AOD climatology presentation in AT2 Aerosol Workshop Bremen June 2007 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 HDF5 File Format Specification http hdf ncsa uiuc edu HDF5 Offline UV Product rer SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 5 19 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 quantities 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 solar noon UV index and quality control flags The product is calculated in a 0 5 degree regular grid and stored in a HDFS file The contents of the product file are listed in chapter 5 An example of the daily erythemal dose product is shown in figure 1 below 1 2 3 4 5 6 7 8 9 10 11 12 Figure 1 An example product field Erythemal CIE daily dose kJ
5. ADATA TO UMARF PARAMETERS18 Offline UV Product REF SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 4 19 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 Basis Document RD1 1 2 Acronyms ATBD Algorithm Theoretical Basis Document AVHRR Advanced Very High Resolution Radiometer CIE Commission Internationale de l clairage International Commission on Illumination EUMETSAT European Organisation for the Exploitation of Meteorological Satellites GOME 2 Global Ozone Monitoring Experiment version 2 HDF Hierarchial Data Format O3M SAF Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring UMARF Unified Meteorological Archiving and Retrieval Facility 1 3 References 1 3 1 Applicable Documents AD1 UMAREF to SAFs ICD EUM UMA ICD 004 Issue 3 13 14 Feb 2007 AD2 UMARF SAF Metadata Definition EUM UMA TEN 030 Issue 1 7 09 Feb 2007 1 3 2 Reference Documents RD1 OUV Algorithm Theoretical Basis Document SAF O3M FMI ATBD 001 Issue 1 2 15 9 2008 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
6. ADATA group is shown in the following table All parameters are stored as attributes of the group The allowed values for the parameters that are required by UMARF are consistent with the requirements given in AD2 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 the UMARF size limit REF ISSUE DATE PAGE User Manual 11 19 Table 2 METADATA group contents SAF OSM FMI PUM 001 1 3 12 02 2009 Attribute name Data Description Allowed values Type SatelliteID string Platform identifier mission and spacecraft the M01 M02 M03 product originated from N15 N16 N17 N18 NI9 etc OrbitType string Orbit type of the spacecraft indicating the LEO coverage of the product InstrumentID string Instrument which acguired the product GOME AVHR SensingStartTime string UTC date and time at acguisition start of the YYYY MM product DDThh mm ss ddd SensingEndTime string UTC date and time at acguisition end of the YYYY MM product DDThh mm ss ddd ProcessingCentre string Centre that generated the data O3FMI ProcessingLevel string Processing level applied for generation of the 03 product ProcessingMode string Processing mode applied for generation of the N Nominal product B Backlogged R Reprocessed V Validation ProcessingTime string UTC date and time at processing end of the YYY
7. Date and Time PPST ProcessingTime Processing End Date and Time GPLV ProcessingLevel Offline UV Product REF SAF 03M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 19 19 UMARF Attribute Name Notes Short Name AVBA BaseAlgorithmVersion AVPA ProductAlgorithmVersion LMAP Map Projection LSCD N A SpatialCoverageModel APXS N A PixelSize SNIT ReferenceTime AENV N A SourceEnvironment GDMD Disposition Mode GPMD ProcessingMode APNM ProductT ype 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 QCCV N A Cloud Coverage QQOV Overall QualityFlag 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 GGTP GranuleType UDSP N A DispositionFlag UMARF internal
8. Offline UV Product REF SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 1 19 DOCUMENT TYPE Product User Manual O3M SAF Offline UV Product User Manual NNN FUNCTION NAME DATE SIGNATURE PREPARED BY Product Manager Jukka Kujanp 12 02 2009 DOCUMENT IDENTIFICATION WBS Nr KEYWORDS SAF O3M FMI PUM OO1 user manual format umarf Offline UV Product rer SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 2 19 DOCUMENT STATUS SHEET Modified Items Reason for Change 15 11 2006 Initial revision of the full document Ee 1 1 04 05 2007 moved algorithm description and error analysis to a separate ATBD as required by EUMETSAT IT updated the file naming convention 04 04 2008 added error fields 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 Offline UV Product REF SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 3 19 TABLE OF CONTENTS Be INTRODUCTION rc 4 1 l Purpose and SCOPE iiec ice tte N ren bie cesses ee edus a pelos ties Res EE LEBER RENERE be Hukat 4 1 2 e renun ya saa 4 M Reference te E 4 1 3 1 Applicable Documints ritiene terr tet rir esee t Pe Lee etr in ee peak ERR rakla 4 153 2 Reterence Documents eniaidaseiniie Ed ec eg a e
9. OualityField Flags have the value 1 for on and 0 for off Bit Name Description 0 QC MISSING Data are missing See table 8 on summary flags 1 QC LOW QUALITY At most low quality expected See table 8 on summary flags 2 QC MEDIUM QUALITY At most medium quality expected See table 8 on summary flags 3 QC INHOMOG SURFACE 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 than the value InhomogeneousSurfaceHeightLimit given in the product specific metadata field table 3 surface albedo within the grid cell and its nearby neighbours deviates more than the value InhomogeneousSurfaceAlbedoLimit given in the product specific metadata field table 3 4 OC POLAR NIGHT Polar night The solar zenith angle is larger than the value PolarNightNoonSza given in the product specific metadata field table 3 5 QC LOW SUN 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 table 3 6 QC OUTOFRANGE INPUT Out of range input data was detected but the value could still be used in processing 7 QC NO CLOUD DATA No cloud data were available 8 QC POOR DIURNAL Poor diurnal cloud coverage This flag is set when insufficient CLOUDS cloud data are available to co
10. Y MM product DDThh mm ss ddd ReferenceTime string Time at which the product is defined to be Same value as valid ProcessingTime ProductAlgorithmVersion string Version of the algorithm that produced the String lt 4 gt product ParentProducts string A list of the name of the parent products upon NTO which the product is based AVHRR level 1b BaseAlgorithmVersion string Version of the NTO product String lt 4 gt ProductT ype string Abbreviated name for the product type or O3MOUV rather product category ProductFormatV ersion string Version number of the product format Issue String lt 4 gt of this User Manual document OverallOualityFlag string Overall guality flag for the product OK or NOK OualityInformation string Several miscellaneous guality indicators for String lt 511 gt the product Offline UV Product REF SAF 03M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 12 19 Attribute name Data Description Allowed values Type 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
11. a Unit Description type 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 GRID_PRODUCT 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 Plant and SCUP h together with integrated UV B 280 315 nm and UV A 315 400 nm radiation In addition the solar noon UV index and its error estimates are stored Attributes attached to all datasets in this group are listed in table 6 The contents of the QualityFlags and the setting of the summary flags are listed in tables 7 and 8 Table 5 GRID PRODUCT group contents Dataset name Data Unit Description type DailyDoseCie float kJ m Daily UV dose CIE weighting DailyDoseCieLow low dose estimate DailyDoseCieHigh high do
12. an integer number of cloud optical thickness observations in the afternoon value 15 indicating 15 or more observations 28 31 QC NOON TO COT 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 8 Mapping of the quality flags to summary flags Summary flag Summary flag is on if any of these flags is on QC MISSING QC POLAR NIGHT QC NO CLOUD DATA QC LOW QUALITY QC MISSING QC LOW SUN QC OUTOFRANGE INPUT QC LUT OVERFLOW QC MEDIUM QUALITY QC LOW QUALITY QC POOR DIURNAL CLOUDS QC HIGHALB CLEARSKY QC INHOMOG SURFACE QC THICK CLOUDS QC ALB CLIM IN DYN REG Offline UV Product REF SAF O3M FMU PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 17 19 5 2 Data Types The data types to be used in the HDFS5 files are given in the table below Table 9 Data types for the HDF5 files Data type HDF5 predefined data type char HST STD ISLE short int HST STD I16LE int HST STD 132LE float HST IEEE F32LE double HST IEEE F64LE string Fortran HST FORTRAN SI C H5T C SI 5 3 File naming convention The file naming convention of the OUV product is shown in Figure 8 O3MOUV L3 YYYYMMDD v01p00 HDF5 processor version minor processor version major day month year Figure 8 The structure of the OUV file
13. ancer Utrecht Philadelphia action spectrum adjusted for human skin Measures the incidence of skin cancer squamous cell carcinoma in human skin SCC The key factors affecting the surface UV radiation are ozone clouds aerosols and surface albedo The sources of these key factors are described below 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 Figure 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 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 relative dose rate 1 L 1 1 L
14. le 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 8 in section 5 1 4 have been designed OC MISSING QC_LOW_QUALITY and QC MEDIUM QUALITY The user is encouraged to use these summary flags as follows e If no quality checking is wanted then the data with QC MISSING equal to 1 should be discarded This is equally achived by checking for fill values in the data e Good and slightly degraded data are obtained by discarding data with QC LOW QUALITY equal to 1 e Good data are obtained by discarding all data with QC MEDIUM equal to 1 The quality flagging procedure will be refined based on the feedback from the validation reports and therefore the mapping in table 8 may change in the future 20070620 Polar Night Flag 20070620 Low Quality Flag ic ix 18 IE oe Figure 4 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 ice sheets other areas with high surface albedo and areas where not insufficient cloud data were available Offline UV Product rer SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 8 19 3 3 Current Quality Is
15. m on 20 June 2007 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 biological entities to UV radiation The currently applied functions are plotted in Figure 2 and a short description of their meaning is given in Table 1 10 F 0 1 p 0 001 1e 04 1e 05 300 320 340 360 380 400 wavelength nm Figure 2 The biological weighting functions table 1 used in the OUV product CIE red DNA green Plant blue and SCUP h purple Offline UV Product rer SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 6 19 Table 1 Description of the biological weighting functions used in the OUV product Weighting Ref Description function CIE RD2 Most often used weighting function It is also known as the erythemal weighting function because it measures the reddening of the skin due to sunburn DNA RD3 Measures the ability of UV irradiance to cause damage to unprotected DNA Normalization to 1 0 at 300 nm is used normalization to 265 nm is divided by 0 0326 Plant RD4 Measures the generalized response of plants to UV irradiance Normalization to 1 0 at 300 nm is used normalization to 280 nm is divided by 0 2176 SCUP h RD5 Skin C
16. n L L 1 2 4 6 8 10 12 14 16 18 20 22 t h Figure 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 The aerosol optical depth is currently taken from climatology RD6 and the surface albedo from the climatology of Tanskanen RD7 Offline UV Product rer SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 7 19 3 PRODUCT QUALITY 3 1 Expected Accuracy and Validation The target product accuracy is 20 against ground based UV measurements The surface UV product is validated by a validation service This service also located at FMI performs two different validation activities Firstly online quality checks are made within the first 30 days of product processing to detect possible degradation of the product quality These quality checks are performed with preliminary ground based reference data Secondly the UV product is fully validated against quality checked ground based measurements These results are provided as half yearly validation reports These validation reports will be available on the O3M SAF web site at http o3msaf fmi fi 3 2 Quality Flags Quality flags table 7 in section 5 1 4 are set during the processing to indicate degraded product quality Figure 4 shows examp
17. ot Bird The NTO product is received at FMI together with input AVHRR level 1b products both from MetOp and NOAA satellites The output OUV product is stored in the FMI Archive from where it can be accessed via the Unified Meteorological Archive and Retrieval Facility UMARF at EUMETSAT The processing data flow is depited in figure 5 below Hot Bird lt EumetCast Av Metop AVHRR LAC LA EumetCast NOAA AVHRR GAC As at reception Usingen station at FMI NTO OUV processor DLR OUV product FMI Archive Product order Order request Product order Product delivery Figure 5 Overall processing data flow 4 2 Product Ordering After the integration of SAF products to the EUMETSAT Unified Meteorological Archive and Retrieval Facility UMARF the HDFS files can be ordered from UMARF at http archive eumetsat int umarf The product order 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 by sending e mail to o3msaf Ofmi fi Offline UV Product REF SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 10 19 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 gro
18. se estimate DailyDoseDna float kJ m Daily UV dose DNA damage weighting DailyDoseDnaLow low dose estimate DailyDoseDnaHigh high dose estimate DailyDosePlant float kJ m Daily UV dose Plant response weighting DailyDosePlantLow low dose estimate DailyDosePlantHigh high dose estimate DailyDoseScuph float kJ m Daily UV dose SCUP h weighting DailyDoseScuphLow low dose estimate DailyDoseScuphHigh high dose estimate DailyDoseUvb float kJ m Daily UV dose integrated UV B 280 315 nm DailyDoseUvbLow low dose estimate Offline UV Product REF SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 14 19 Dataset name Data Unit Description type DailyDoseUvbHigh high dose estimate DailyDoseUva float kJ m Daily UV dose integrated UV A 315 400 nm DailyDoseUvaLow low dose estimate DailyDoseUvaHigh high dose estimate DailyMaxDoseRateCie float mW m Daily maximum dose rate CIE weighting DailyMaxDoseRateCieLow low dose rate estimate DailyMaxDoseRateCieHigh high dose rate estimate DailyMaxDoseRateDna float mW m Daily maximum dose rate DNA damage weighting DailyMaxDoseRateDnaLow low dose rate estimate DailyMaxDoseRateDnaHigh high dose rate estimate DailyMaxDoseRatePlant float mW m Daily maximum dose rate Plant response weighting DailyMaxDoseRatePlantLow low dose rate estimate DailyMaxDoseRatePlantHigh high do
19. se rate estimate DailyMaxDoseRateScuph float mW m Daily maximum dose rate SCUP h weighting DailyMaxDoseRateScuphLow low dose rate estimate DailyMaxDoseRateScuphHigh high dose rate estimate DailyMaxDoseRateU vb float mW m Daily maximum dose rate integrated UV B 280 315 nm DailyMaxDoseRateUvbLow low dose rate estimate DailyMaxDoseRateU vbHigh high dose rate estimate DailyMaxDoseRateUva float mW m Daily maximum dose rate integrated UV A 315 400 nm DailyMaxDoseRateUvaLow low dose rate estimate DailyMaxDoseRateU vaHigh high dose rate estimate SolarNoonUvIndex float N A Solar noon UV index SolarNoonUvIndexLow low index estimate SolarNoonUvIndexHigh high index estimate QualityFlags int N A Ouality flags for the product See table 7 for interpretation of the bits Offline UV Product per User Manual SAF O3M FMI PUM 001 ISSUE 1 3 DATE 12 02 2009 PAGE 15 19 Table 6 Attributes for the GRID PRODUCT group datasets Attribute name Data Type Description Title string Description of the dataset e g Solar noon UV index Unit string Unit of the values in the array e g second FillValue same as the Number in the array if actual data value is missing dataset ValidRangeMin same as the Minimum allowed value for the data in the array dataset ValidRangeMax same as the Maximum allowed value for the data in the array dataset Table 7 Interpretation of the
20. sues The estimation of effective cloud optical depth from the AVHRR reflectances becomes prone to errors if the solar zenith angle is larger than 70 degrees or if the surface albedo is high and therefore the corresponding product values are flagged as of low guality 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 climatology fails during snow falling and melting periods which vary from year to year The aerosol climatology on the other hand tends to underestimate the aerosol loading in the boundary layer especially during the summer time Offline UV Product REF SAF O3M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 9 19 4 PROCESSING ARCHIVING AND DISSEMINATION 4 1 Processing and Archiving The offline UV product is produced operatively 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 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 H
21. ups METADATA PRODUCT SPECIFIC METADATA GRID DESCRIPTION and GRID PRODUCT The file structure is shown in Figure 6 The values in all groups are either copied from the input data or calculated by the processor METADATA PRODUCT SPECIFIC METADATA GRID DESCRIPTION GRID PRODUCT Figure 6 Structure of the HDF5 file The METADATA group contains the parameters required by UMARF ADI AD2 while the PRODUCT SPECIFIC METADATA 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 GRID DESCRIPTION group whereas the product fields are stored as datasets in the GRID PRODUCT 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 FillValue ValidRangeMin and ValidRangeMax These are used to describe the contents of the array The organization of the data is illustrated in Figure 7 XNumCells e a S o Oo Ba n E o O E Z YStepDeg S YStartLat lt gt t Longitude x XStartLon XStepDeg Figure 7 Organization of the product fields in the HDF5 file Offline UV Product 5 1 1 METADATA Group The content of the MET
22. ver the diurnal cloud cycle 9 QC THICK CLOUDS 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 table 3 Offline UV Product REF SAF 03M FMI PUM 001 User Manual ISSUE 1 3 DATE 12 02 2009 PAGE 16 19 Bit Name Description 10 OC ALB CLIM IN Surface albedo climatology was used in a dynamic region where DYN REG albedo varies with the snow and ice cover 11 QC LUT OVERFLOW Look up table limits were exceeded and a value was extrapolated 12 OC HIGHALB CLEARSKY Clear sky was assumed if surface albedo was larger than the value HighAlbedoClearSky and surface pressure was smaller than the value HighAlbedoClearSkyPatm given in the product specific metadata field 13 15 reserved for future use 16 19 QC OZONE SOURCE 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 20 23 QC NUM AM COT 4 bits as an integer number of cloud optical thickness observations in the morning value 15 indicating 15 or more observations 24 27 QC NUM PM COT 4 bits as
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