Sentinel-3 Marine Test Data Set processed at EUMETSAT

Transcription

1 Sentinel-3 Marine Test Data Set processed at EUMETSAT Doc.No. : EUM/TSS/TEN/15/ Issue : v2 e-signed Date : 15 December 2015 WBS/DBS : EUMETSAT Eumetsat-Allee 1, D Darmstadt, Germany Tel: Fax: EUMETSAT The copyright of this document is the property of EUMETSAT.

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3 Document Change Record Issue / Revision Date DCN. No Changed Pages / Paragraphs V Draft version only one PDU V1A First version - full orbit of SLSTR L1 and OLCI L1 FR data V1B Version prepared for publishing V Added SRAL L1b data from STC production chain, consolidated main document body and added some new limitations to existing data. Page 3 of 18

4 Table of Contents 1 INTRODUCTION Purpose Scope Reference Documents MARINE USER TDS Overview Contents TDS Generation Data Visualisation TDS Delivery Feedback on TDS SLSTR TDS Description SLSTR current limitations OLCI TDS Description OLCI current limitations SRAL TDS Description SRAL current limitations APPENDIX A SUMMARY OF CURRENT LIMITATIONS APPENDIX B PRODUCT LIST Table of Figures Figure 1. Example of footprints for different grids in one PDU for selected product SL_1_RBT : footprint defined in manifest file (red), 1 km nadir (yellow) and 1 km oblique (black) view Figure 2. Example of brightness temperatures of channel S8 for nadir (left) and oblique (right) view.. 11 Figure 3. Example of OL_1_EFR top of the atmosphere (TOA) radiance in band 1 (left) and band 10 (right). All values in selected TOA radiance bands are plotted, regardless of the flag values Figure 4: Footprints of the ground tracks for the TDS pole-to-pole passes Figure 5: Ku SAR Waveforms Data for Orbit Figure 6: Ku LRM Waveforms Data for Orbit Table of Tables Table 1. Estimated product sizes of this TDS. Based on the compression rate, size of the operational products can vary Table 2. TDS production elements... 8 Table 3.Simulated orbit characteristics for OLCI and SLSTR... 8 Table 4.Simulated orbit characteristics for SRAL... 8 Table 5. List of current limitations Table 6. List of PDUs and corresponding sizes Page 4 of 18

5 1 INTRODUCTION 1.1 Purpose A Sentinel-3 marine simulated Test Data Set (TDS) is generated by Payload Data Ground Segment (PDGS) deployed at the EUMETSAT Sentinel-3 Marine Centre. It represents the data that are produced using the current version of the Processing Facility. It has to be noted that the version of Processing Facility and the products specification might evolve after the release of this TDS with the consequent change of their content and format. This Technical Note provides a description of the Sentinel-3 marine simulated OLCI/SLSTR/SRAL L1 TDS, its structure and contents, its limitations and open issues. It explains how to access the TDS and feed-back comments to EUMETSAT. This Issue addresses the Version 2 of the Marine TDS. It is expected that this document will be updated for future versions of the S3 Marine TDS when OLCI/SLSTR/SRAL L2 products will become available. It is encouraged that the users interested in this products but also in the updated version of available TDS, send to ops@eumetsat.int with the subject Sentinel-3 Marine TDS subscription. EUMETSAT help desk will ensure that interested users will receive the last available TDS with updated Technical Note describing the data and updates. 1.2 Scope This Technical Note is aimed for the wide Users community that are preparing tools and applications for marine Sentinel-3 products and want to have access to Sentinel-3 SAFE product formats. Since the data values are not scientifically meaningful, it is not expected to be used for scientific testing. 1.3 Reference Documents RD-1 Sentinel-3 Optical User TDS description RD-2 Product Data Format Specification - SRAL/MWR Level 1 & 2 Instrument Product RD-3 Product Data Format Specification - OLCI Level 1 & 2 Instrument Product RD-4 Product Data Format Specification - SLSTR Level 1 & 2 Instrument Product 3 S3IPF.PDS.003 S3IPF.PDS.004 S3IPF.PDS.005 Page 5 of 18

6 RD-5 GMES Space Component - Sentinel-3 Payload Data Ground Segment Products Definition Document GMES-S3GS-EOPG-TN EUM/LEO-SEN3/TEN/13/ RD-6 Sentinel-3 S3-TDS Generation for L2 SRAL/MWR IPF CLS-DOS-NT Page 6 of 18

7 2 MARINE USER TDS 2.1 Overview A Sentinel-3 marine simulated TDS is generated by PDGS deployed at the EUMETSAT Sentinel-3 Marine Centre. It represents the data that are produced using the latest available Instrument Processing Facility (IPF) version and, with a few smaller modifications, representative of the processing that will be used after the launch of Sentinel-3A. In particular the product format should closely resemble the format that will be available during the commissioning phase, allowing users to get experience with the Sentinel-3 SAFE marine products. This TDS is complementary to scientifically meaningful TDS distributed by ESA (RD-1, RD-6) because it represents the data generated directly by the PDGS facility, but with very limited scientifically meaningful content. Therefore, users are advised to use both the scientific TDS mentioned above and this simulated TDS to prepare tools and applications for their upcoming Sentinel-3 activities. Some limitations and open issues in this TDS are listed below and under investigation. Users are invited to note those, to have a detailed and critical view and to provide feedback to EUMETSAT Contents This TDS covers L1 products from both optical and surface topography mission (STM). Optical TDS contains one simulated orbit of OLCI Level 1 full resolution (FR) and SLSTR Level 1 products distributed in 3 minute Product Dissemination Units (PDUs): - OLCI: OL_1_EFR - SLSTR: SL_1_RBT STM TDS contains 6 simulated descending pole-to-pole (i.e. ~ 50 minute long PDU) SRAL L1b passes in STC timeliness. - SRAL: SR_1_SRA SRAL L2, SLSTR L2 and OLCI RR L1 and L2 (RR/FR) from other production chains will be distributed to users in a future version. The following table ( Page 7 of 18

8 Table 1) gives the estimated size of the TDS. For the exact size of PDUs please refer to Table 6 in Appendix B. Page 8 of 18

9 Table 1. Estimated product sizes of this TDS. Based on the compression rate, size of the operational products can vary. Product name PDU size (MB) Cumulative size for one orbit (GB) SL_1_RBT MB ~13 GB OL_1_EFR MB ~ 5 GB SR_1_SRA MB ~ 0.05 GB TDS Generation The TDSs provided to users include simulated high level products produced by the Sentinel-3 Marine PDGS. Products are provided in PDUs, defined as portion of data [RD-5] in order to ease the online dissemination and data handling for the users. These PDUs are produced by the following elements: Table 2. TDS production elements OLCI IPF version 5.02 SLSTR IPF version 5.02 SRAL IPF version 5.02 For OLCI and SLSTR payload, PDUs are generated by Product Unit Generation Facility (PUGF) in the near real time (NRT) processing chain in frames [RD-5] with the length of 3 minutes. For SRAL payload in the L1b short time critical (STC) processing chain, PUGF generates PDUs in pole-to-pole passes [RD-5] with an approximate length of 50 minutes. We will give brief information on selected Sentinel-3 marine products, and report some existing limitations. One orbit (#287) is selected for OLCI Level 1 FR and SLSTR Level 1 in NRT production chain (Table 3) and 6 descending pole-pole passes of SRAL L1 in STC production chain (Table 4). All PDU filenames are listed in Table 6 of Appendix B. Table 3.Simulated orbit characteristics for OLCI and SLSTR Orbit 287 UTC Time at ascending node T23:19: Z Position at ascending node in Earth Fixed X: frame [m] Y: Z: Table 4.Simulated orbit characteristics for SRAL Orbit 285 UTC Time at ascending node T19:57: Z Position at ascending node in Earth Fixed X: frame [m] Y Z: Page 9 of 18

10 Orbit 286 UTC Time at ascending node T21:38: Z Position at ascending node in Earth Fixed X: frame [m] Y Z: Orbit 289 UTC Time at ascending node T02:41: Z Position at ascending node in Earth Fixed X: frame [m] Y Z: Orbit 290 UTC Time at ascending node T04:22: Z Position at ascending node in Earth Fixed X: frame [m] Y Z: Orbit 291 UTC Time at ascending node T06:03: Z Position at ascending node in Earth Fixed X: frame [m] Y Z: Orbit 293 UTC Time at ascending node T09:25: Z Position at ascending node in Earth Fixed X: frame [m] Y Z: Data Visualisation For visualising data or accessing the manifest file users are encouraged to use the Sentinel-3 Toolbox [RD-1] or any other tool able to visualise NetCDF-4 and read XML files (Python, Matlab/Octave, IDL,...). Page 10 of 18

11 2.1.4 TDS Delivery TDS are available at the following URL: ftp://ftp.eumetsat.int/pub/ops/out/test-data/sentinel-3a_test_data/ The TDS directory structure is as follows: OLCI_(Ocean_Land_Colour_Instrument)/ Level-1_Full_Resolution/ OL_1_EFR NRT/ SLSTR_(Sea_Land_Surface_Temperature_Radiometer)/ Level-1/ SL_1_RBT NRT/ SRAL_(SAR_Radar_ALtimeter)/ Level-1/ SR_1_SRA STC/ Feedback on TDS TDS users are invited to provide comments on the TDS by to the EUMETSAT Help Desk 2.2 SLSTR TDS Description The SLSTR product data format specification (PDS) document [RD-4] describes SLSTR Level 1 and Level 2 products in detail. This TDS contains one orbit of SL_1_RBT Level 1 in NRT (two PDUs are missing). The estimated size for one PDU and for one orbit of SL_1_RBT product is shown in Page 11 of 18

12 Table 1. It should be noted that this products are internally compressed (compression ratio 2) and the sizing is based on simulated data. Therefore the size of the real product can differ from these values. Figure 1 shows an example of footprints for different grids in one selected SL_1_RBT PDU: 1 km nadir view (yellow), 1 km oblique view (black) and satellite footprint defined in manifest file (red). Example of band S8 nadir and oblique view brightness temperatures (Figure 2) shows simulated values over the whole acquisition area. Figure 1. Example of footprints for different grids in one PDU for selected product SL_1_RBT : footprint defined in manifest file (red), 1 km nadir (yellow) and 1 km oblique (black) view. Page 12 of 18

13 Figure 2. Example of brightness temperatures of channel S8 for nadir (left) and oblique (right) view SLSTR current limitations 1. Missing two SL_1_RBT PDUs from the full orbit. 2. Satellite footprint points defined in the manifest file are not sorted correctly for several SL_1_RBT products. 3. Measurement values along the SL_1_RBT product edges contain missing values. 4. Some missing values along the scan line are not correctly flagged. 5. Meteorological variables are not filled with correct values. 6. Discrepancy between the acquisition start/stop times defined in the manifest file, in the global attribute header of data files and of the data itself (e.g. time_in.nc). 2.3 OLCI TDS Description OLCI product data format specification (PDS) document [RD-3] describes OLCI Level 1 and Level 2 products in detail. This TDS contains one orbit of OL_1_EFR L1 full resolution products. Similar to SLSTR, Page 13 of 18

14 Table 1 shows the estimated size for one PDU and the size of the one orbit. Again, it should be noted that this product sizing is based on simulated data and the size of the real product can significantly differ from this values. Figure 3 shows example of simulated top of the atmosphere radiances for band 1 and 10 for one OL_1_EFR PDU selected over the same area and covering the same acquisition time as shown for SLSTR (Figure 2). Figure 3. Example of OL_1_EFR top of the atmosphere (TOA) radiance in band 1 (left) and band 10 (right). All values in selected TOA radiance bands are plotted, regardless of the flag values OLCI current limitations 1. Two OL_1_EFR PDUs have shorter duration time. 2. Measurement values along the OLCI product edges are filled with zeros, and the _FillValue is defined as 65535US. 3. There is a discontinuity in geodetic longitude/latitude OLCI L1 products and values. These values are flagged as invalid pixels (and therefore not shown in S3TBX). 4. Discrepancy between the acquisition start/stop times defined in the manifest file, in the global attribute header of data files and of the data itself (time_coordinates.nc). 2.4 SRAL TDS Description SRAL product data format specification (PDS) document [RD-2] describes SRAL L1 and L2 products in detail. Page 14 of 18

15 In this TDS version, 6 descending pole-to-pole STC L1b passes are available (orbit number 285, 286, 289, 290, 291 and 293). The corresponding ascending passes are not delivered. The estimated size for one L1b pass (PDU) and for the full orbit of L1b SR_1_SRA product is shown in Page 15 of 18

16 Table 1. Again, it should be noted that this product sizing is based on simulated data and the size of the real product can differ from this values. The products may feature some temporal gaps of around 0.25 seconds. These gaps are due to the transition between SAR mode and LRM mode (and vice versa) or the lost/corrupt source packets; they are anyhow logged in the manifest file. The Figure 4 shows the footprints for the 6 descending passes (blue is LRM mode and red is SAR mode). Figure 4: Footprints of the ground tracks for the TDS pole-to-pole passes The Figure 5 and Figure 6 Figure 4show respectively the Ku Waveforms Data for the SAR mode and LRM mode for the orbit 285 (descending pass). Page 16 of 18

17 Figure 5: Ku SAR Waveforms Data for Orbit 285 Figure 6: Ku LRM Waveforms Data for Orbit 285 We stress again that the data are not scientifically meaningful and therefore users should use the data mainly to get familiar to the Sentinel-3 SAFE format and build the software interfaces to it SRAL current limitations 1. Non-conformance to CF 1.6 convention. 2. Discrepancy between the product name as reported in the manifest and the product name as reported in the global attribute header of the measurement data file 3. Discrepancy between the sensing start/stop time in the manifest and in the global attribute header of measurement/annotation data files. 4. Inconsistency between the product footprint as reported in the product manifest and real footprint of the product (lat/lon in the measurement data file). Page 17 of 18

18 APPENDIX A SUMMARY OF CURRENT LIMITATIONS Table 5. List of current limitations. Instrument Current limitations SLSTR - Missing two SL_1_RBT PDUs from the full orbit. - One SL_1_RBT PDU has shorter duration time. - Satellite footprint points defined in the manifest file are not sorted correctly for several SL_1_RBT products. - Measurement values along the SL_1_RBT product edges contain missing value. - Some missing values along the scan line not correctly flagged in SL_1_RBT. - Meteorological variables within met_tx.nc annotation data file are filled with constant non-meaningful values. - Discrepancy between the acquisition start/stop times defined in the manifest file, in the global attribute header of data files and of the data itself. OLCI - Two OL_1_EFR PDUs have shorter duration time. - Measurement values along the OL_1_EFR product edges are filled with zeros, and the _FillValue is defined as 65535US. - There is a discontinuity in geodetic longitude/latitude OL_1_EFR products and values. These values are flagged as invalid pixels (and therefore not shown in S3TBX). - Discrepancy between the acquisition start/stop times defined in the manifest file, in the global attribute header of data files and of the data itself. SRAL - Non-conformance to CF 1.6 convention. - Discrepancy between the product name as reported in the manifest and the product name as reported in the global attribute header of the measurement data file - Discrepancy between the sensing start/stop time in the manifest and in the global attribute header of measurement/annotation data files. - Inconsistency between the product footprint as reported in the product manifest and real footprint of the product (lat/lon in the measurement data file). Page 18 of 18

19 APPENDIX B PRODUCT LIST Table 6. List of PDUs and corresponding sizes. Instrument Product file name SLSTR SL_1_RBT 391M 358M 381M 354M 354M 135M 389M 346M 308M 389M 353M 369M 353M 335M 310M 288M 364M 299M 286M 351M 348M 295M 309M 349M 342M 341M 337M 350M 349M 346M S3A_SL_1_RBT T234917_ T235216_ T181829_ 0179_015_287_1768_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T235517_ T235816_ T183903_ 0179_015_287_2128_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T235217_ T235516_ T181959_ 0179_015_287_1948_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T234617_ T234916_ T183432_ 0179_015_287_1588_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T234317_ T234616_ T183334_ 0179_015_287_1408_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T233612_ T233716_ T183747_ 0064_015_287_0984_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T233717_ T234016_ T183758_ 0179_015_287_1048_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T000717_ T001016_ T192816_ 0179_015_287_2848_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T003117_ T003416_ T203150_ 0179_015_287_4288_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T234017_ T234316_ T184144_ 0179_015_287_1228_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T233117_ T233416_ T192246_ 0179_015_287_0688_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T001017_ T001316_ T192541_ 0179_015_287_3028_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T235817_ T000116_ T192523_ 0179_015_287_2308_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T000417_ T000716_ T192632_ 0179_015_287_2668_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T001617_ T001916_ T193349_ 0179_015_287_3388_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T002517_ T002816_ T201743_ 0179_015_287_3928_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T232517_ T232816_ T191752_ 0179_015_287_0328_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T001317_ T001616_ T193223_ 0179_015_287_3208_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T002217_ T002516_ T193637_ 0179_015_287_3748_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T232817_ T233116_ T192140_ 0179_015_287_0508_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T000117_ T000416_ T192745_ 0179_015_287_2488_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T001917_ T002216_ T193530_ 0179_015_287_3568_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T002817_ T003116_ T203110_ 0179_015_287_4108_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T005517_ T005816_ T203656_ 0179_015_287_5728_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T005817_ T010116_ T204025_ 0179_015_287_5908_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T004917_ T005216_ T204204_ 0179_015_287_5368_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T005217_ T005516_ T204259_ 0179_015_287_5548_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T004017_ T004316_ T204753_ 0179_015_287_4828_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T004317_ T004616_ T204834_ 0179_015_287_5008_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T004617_ T004916_ T204942_ 0179_015_287_5188_MAR_O_NR_001.SEN3 Page 19 of 19

20 308M 342M S3A_SL_1_RBT T003417_ T003716_ T205349_ 0179_015_287_4468_MAR_O_NR_001.SEN3 S3A_SL_1_RBT T003717_ T004016_ T205444_ 0179_015_287_4648_MAR_O_NR_001.SEN3 OLCI OL_1_EFR 13M 445M 385M 374M 428M 392M 404M 364M 366M 365M 376M 133M 439M 413M 391M S3A_OL_1_EFR T234012_ T234016_ T174736_ 0004_015_287_1224_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T234017_ T234316_ T172652_ 0179_015_287_1228_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T234317_ T234616_ T172852_ 0179_015_287_1408_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T234617_ T234916_ T174223_ 0179_015_287_1588_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T234917_ T235216_ T175947_ 0179_015_287_1768_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T235217_ T235516_ T181111_ 0179_015_287_1948_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T001317_ T001616_ T193244_ 0179_015_287_3208_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T000117_ T000416_ T200619_ 0179_015_287_2488_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T235517_ T235816_ T181914_ 0179_015_287_2128_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T235817_ T000116_ T183254_ 0179_015_287_2308_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T000717_ T001016_ T184310_ 0179_015_287_2848_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T000612_ T000716_ T192146_ 0064_015_287_2784_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T001617_ T001916_ T190439_ 0179_015_287_3388_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T001017_ T001316_ T191232_ 0179_015_287_3028_MAR_O_NR_001.SEN3 S3A_OL_1_EFR T001917_ T002216_ T194438_ 0179_015_287_3568_MAR_O_NR_001.SEN3 SR_1_SRA SRAL 26.6M S3A_SR_1_SRA T202304_ T211334_ T164300_ 3029_015_285 MAR_O_ST_001.SEN3 26.8M S3A_SR_1_SRA T220404_ T225434_ T164659_ 3029_015_286 MAR_O_ST_001.SEN3 31.1M S3A_SR_1_SRA T030701_ T035731_ T200940_ 3029_015_289 MAR_O_ST_001.SEN3 31.4M S3A_SR_1_SRA T044801_ T053830_ T191240_ 3029_015_290 MAR_O_ST_001.SEN3 31.5M S3A_SR_1_SRA T062900_ T071930_ T215751_ 3029_015_291 MAR_O_ST_001.SEN3 31.7M S3A_SR_1_SRA T095058_ T104128_ T182139_ 3029_015_293 MAR_O_ST_001.SEN3 Page 20 of 20