Sentinel-5P卫星1级数据介绍.pdf-资料库

u014594891-12788685-4744300845135370729.pdf-第1页.png

第1页 / 共17页

u014594891-12788685-4744300845135370729.pdf-第2页.png

第2页 / 共17页

u014594891-12788685-4744300845135370729.pdf-第3页.png

第3页 / 共17页

u014594891-12788685-4744300845135370729.pdf-第4页.png

第4页 / 共17页

u014594891-12788685-4744300845135370729.pdf-第5页.png

第5页 / 共17页

u014594891-12788685-4744300845135370729.pdf-第6页.png

第6页 / 共17页

u014594891-12788685-4744300845135370729.pdf-第7页.png

第7页 / 共17页

u014594891-12788685-4744300845135370729.pdf-第8页.png

第8页 / 共17页

S5P Mission Performance Centre Level 1b Readme L01b Design Lead MPC ESL-L1 Product Lead MPC ESL-L1b Product Contributor MPC ESL-L1b Product Contributor MPC ESL-L1b Product Contributor ESA Data Quality Manager ESA Mission Manager document number S5P-MPC-KNMI-PRF-L1B 2.2.0 2019-10-31 V01.00.00 released N.C. Rozemeijer (KNMI) Q. Kleipool (KNMI) A. Ludewig (KNMI) T. van Kempen (SRON) R. van Hees (SRON) A. Dehn (ESA) C. Zehner (ESA) issue date product version status Prepared by Reviewed by Approved by

S5P MPC Product Readme Level 1b V01.00.00 issue 2.2.0, 2019-10-31 - released MPC Contributors S5PVT1 Contributors E. Loots (KNMI) R. Bartstra (KNMI) E. van der Plas (KNMI) M. Weber (IUP) G. Jaross (NASA) J. Gleason (NASA) G. Tilstra (KNMI) S5P-MPC-KNMI-PRF-L1B Page 2 of 17 MPC ESL-L1 Product Contributor MPC ESL-L1 Product Contributor MPC ESL-L1 Product Contributor S5PVT, AO Project 28608 S5PVT, NASA Project, AO 28612 S5PVT, NASA Project, AO 28612 S5PVT, AO Project 28617 Signatures C. Zehner (ESA) – Mission Manager 1 The S5PVT AO project summaries can be found at https://earth.esa.int/web/guest/pi- community/search-results-and-projects/mission XMPC Product Lead / PRF Lead EditorXA. Dehn (ESA)Data Quality Manager

S5P MPC Product Readme Level 1b V01.00.00 issue 2.2.0, 2019-10-31 - released 1 Summary S5P-MPC-KNMI-PRF-L1B Page 3 of 17 This is the Product Readme File (PRF) for the Sentinel 5 Precursor Tropospheric Monitoring Instrument (S5P/TROPOMI) Level 1b data products and is applicable for both the Near Real-Time (NRTI) and Offline (OFFL) timeliness data products. The S5p mission is a single-payload satellite in a low Earth orbit that provides daily global information on concentrations of trace gases and aerosols important for air quality, climate forcing, and the stratospheric ozone layer. The payload of the mission is the TROPOspheric Monitoring Instrument (TROPOMI), which is jointly developed by The Netherlands and ESA. The instrument consists of a spectrometer with spectral bands in the ultraviolet, the visible, the near-infrared and the shortwave infrared, as detailed in Table 1. The wavelength range for TROPOMI allows observation of key atmospheric constituents, including ozone (O3), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), methane (CH4), formaldehyde (CH2O), aerosols and clouds. Starting from orbit 9388 on 6 August 2019, a modification in the operations scenario increased the spatial sampling in the flight direction. Due to this change the approximate footprint size in nadir improved from 7 x 3.5 km2 to 5.5 x 3.5 km2. Table 1 Main spectral characteristics of the four TROPOMI spectrometers and the definition of the TROPOMI spectral bands with identifiers 1–8. There are 2 different types of L1b data products available to users: • L1b radiance products, containing earth radiance spectra. There is one L1b radiance product type for each spectral band (product identifiers L1B_RA_BD1 through L1B_RA_BD8). • L1b irradiance products, containing solar irradiance spectra. There are two L1b irradiance products types. The first (product identifier L1B_IR_UVN) contains the solar irradiance spectra for the UVN bands (band 1 through band 6). The second (product identifier L1B_IR_SIR) contains the solar irradiance spectra for the SWIR bands (band 7 and band 8). The L1b radiance and irradiance products are available to users in off-line (OFFL) timeliness. Off-line data products contain one orbit worth of data. Example filename: S5P_OFFL_L1B_RA_BD4_20180703T020255_20180703T034425_03727_01_010000_20180703T053339.nc This document describes the current processing baseline, product and quality limitations, and product availability status. More information on this data product is available from the Sentinel product webpage: https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-5p/products-algorithms, and from the TROPOMI product webpage http://www.tropomi.eu/data-products. The L1B Mission data requirements are described in [MRD].

S5P MPC Product Readme Level 1b V01.00.00 issue 2.2.0, 2019-10-31 - released 2 Processing baseline description S5P-MPC-KNMI-PRF-L1B Page 4 of 17 This ReadMe applies to S5p/TROPOMI Level 1B data products, produced with L0-1b data processor version 01.00.00 and calibration key data: S5P_OPER_AUX_L1_CKD_20141001T000001_20501231T235959_00000_01_001200_20171010T1 43000.h5. Table 2 contains the history of the processor versions. Processor Version In operation from In operation until 01.00.00 orbit 2818, 2018-04-30 current version Table 2: History of S5p Level 1B processor versions

S5P MPC Product Readme Level 1b V01.00.00 issue 2.2.0, 2019-10-31 - released 3 Product Quality 3.1 Recommendations for data usage S5P-MPC-KNMI-PRF-L1B Page 5 of 17 An overview of the Sentinel-5p mission, the TROPOMI instrument and the algorithms for producing the L1b data products can be found in the Algorithm Theoretical Basis Document [ATBD]. Details of the data format are provided in the Input/Output Data Specification [IODS]. The metadata contained in the L1b data products are described in the Metadata Specification [MDS]. All these documents are available https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-5p/products- algorithms. on For Level 2 processing, the following additional notices apply: • The L0-1b data processor annotates the data with quality assessment data in the fields spectral_channel_quality, measurement_quality and ground_pixel_quality. Level 2 developers are strongly encouraged to use these quality fields in their retrievals and exclude flagged data as needed. • All 8 bands are processed individually in the L0-1b data processor. In case of missing data, for example in case of data drop-outs during downlinks, this does not necessarily impact all bands (to the same extent). This means that a scanline can be missing for some bands, where it is not missing for other bands. When combining data from multiple bands, Level 2 algorithm developers should therefore always check and match the delta_time for these data and, in case of non-co- registered bands, the geolocation as well. • For calculating reflectance from the radiance products, it is recommended to use the irradiance product with the sensing time closes to the sensing time of the radiance product. 3.2 Validation results 3.2.1 Status of product validation This section presents a summary of the key validation results obtained by the Validation data Analysis Facility (VDAF) of the S5p Mission Performance Centre (MPC) and by the S5p Validation Team (S5PVT). It contains preliminary results reported at the S5p First Public Release Validation Workshop (ESA/ESRIN, June 25-26, 2018). Individual contributions to the workshop are available in https://nikal.eventsair.com/QuickEventWebsitePortal/sentinel-5p-first-product-release- workshop/sentinel-5p, while up-to-date validation results and consolidated validation reports are available through the MPC VDAF website at http://mpc-vdaf.tropomi.eu. Current conclusions are based on the limited amount of reference measurements available at the time of this first analysis, and on a period covered by the initial S5P dataset. The conclusions summarized hereafter need to be confirmed by a larger amount of co-locations, and extended over a full year of data, hence, a full cycle of key influence quantities, in order to enable detection and quantification of potential patterns, dependences, seasonal cycles and longer term features. 3.2.2 Validation approach The S5P/TROPOMI Level 1b products have been compared to models and other satellite instruments, specifically EOS-Aura OMI and NPP OMPS. 3.2.3 Validation results The validation of the wavelength assignment of the UVN L1b products shows agreement of 0.02 to 0.04 nm, which is within the pre-launch calibration accuracy. Initial validation of the reflectance with OMI and OMPS data indicates that TROPOMI is within 5% for the shorter wavelengths in band 3 and improving to 2% towards the longer wavelengths in band 4. For the short wave UV in band 1 TROPOMI is within 8% +/-2% of the expected modeled reflectances. In general radiometric errors in bands 1 and 3 are large but vary slowly over wavelength and most L2 retrievals are insensitive to such errors. Additional validation indicates that for bands 3 to 7 the requirements [MRD] for the reflectance are met if the uncertainty of the method of 3 to 5% is taken into account.

S5P MPC Product Readme Level 1b V01.00.00 issue 2.2.0, 2019-10-31 - released The largest source of error in the reflectance is due to the initial pre-launch irradiance calibration. This is a known issue and will be addressed in future updates. S5P-MPC-KNMI-PRF-L1B Page 6 of 17 The validation of the TROPOMI irradiance L1b product shows that it is within 3 to 10% depending on the used reference spectrum and that there is a radiometric mismatch between band 2 and 3.

S5P MPC Product Readme Level 1b V01.00.00 issue 2.2.0, 2019-10-31 - released 4 Known Data Quality Issues S5P-MPC-KNMI-PRF-L1B Page 7 of 17 4.1 Radiometric calibration and degradation Several issues have been identified with respect to the radiometric calibration of the instrument and possible degradation: • Irradiance measurements show a spatial non-uniformity. This, non-uniformity is probably caused by uncorrected setup straylight during on-ground calibration. Furthermore, in-flight diffuser degradation seems to result in an increase in the non-uniformity. The spatial non-uniformity (in this case for the UVIS detector) is shown in Figure 1. Figure 1 (a) shows the measured solar irradiance on the detector. In Figure 1 (b), the data are regridded to a fixed wavelength grid. In Figure 1 (c) the irradiance is divided by the irradiance of the central detector row (corresponding to nadir), showing the non-uniformity. (a) (b) (c) Figure 1 Spatial non-uniformity in irradiance measurements. • There is a long-term downward trend in irradiance signal magnitude, probably due to diffuser degradation. The drift is strongest for shorter wavelengths and negligible in NIR and SWIR. However, there is also a low-frequency periodic additional signal on top of this drift. This second drift is visible in UV, VIS and NIR. It even dominates the diffuser degradation for NIR. The spectrally averaged drift is shown in Figure 2. Figure 2 Temporal drift in the irradiance for UV (left), UVIS (middle) and NIR (right). The y-axis corresponds with time (orbit) from top to bottom, the x-axis corresponds to detector row (ground-pixel dimension)

S5P MPC Product Readme Level 1b V01.00.00 issue 2.2.0, 2019-10-31 - released • There is a discrepancy between the L1b signals in the spectrally overlapping regions of bands 2 and 3. This discrepancy is observed for irradiance as well as radiance and WLS calibration measurements. Figure 3 (a) shows the discrepancy in the irradiance signal for orbit 492, which is in the order of 5%. The discrepancy appears to increase with time, as shown in Figure 3 (b). S5P-MPC-KNMI-PRF-L1B Page 8 of 17 Figure 3 Discrepancy between band 2 and 3 for orbit 492 (a) and the trend of the discrepancy over time (b) (a) (b) to increase over • The signals on the UV detector (band 1 and band 2) are contaminated with a spectral fingerprint, that appears in WLS calibration measurements, as shown in Figure 4, but is expected to be present in radiance and irradiance measurements as well. This fingerprint shows a clear correlation with the irradiance spectrum, as shown in Figure 5. For level 2 processing, in case the reflectance is calculated using a measured irradiance spectrum close to the sensing time to the radiance measurements, this effect is expected to cancel out to a large extent. fingerprint was observed time. This Figure 4 Spectral fingerprint for various orbits, as observed using WLS calibration measurements

资料库

Sentinel-5P卫星1级数据介绍.pdf

相关推荐

课程资源

热门标签

最新资料