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Fundamental Data Record for Atmospheric Composition [ATMOS__L1B]
The Fundamental Data Record (FDR) for Atmospheric Composition UVN v.1.0 dataset is a cross-instrument Level-1 product [ATMOS__L1B] generated in 2023 and resulting from the ESA FDR4ATMOS project. The FDR contains selected Earth Observation Level 1b parameters (irradiance/reflectance) from the nadir-looking measurements of the ERS-2 GOME and Envisat SCIAMACHY missions for the period ranging from 1995 to 2012. The data record offers harmonised cross-calibrated spectra with focus on spectral windows in the Ultraviolet-Visible-Near Infrared regions for the retrieval of critical atmospheric constituents like ozone (O3), sulphur dioxide (SO2), nitrogen dioxide (NO2) column densities, alongside cloud parameters. The FDR4ATMOS products should be regarded as experimental due to the innovative approach and the current use of a limited-sized test dataset to investigate the impact of harmonization on the Level 2 target species, specifically SO2, O3 and NO2. Presently, this analysis is being carried out within follow-on activities. The FDR4ATMOS V1 is currently being extended to include the MetOp GOME-2 series. Product format For many aspects, the FDR product has improved compared to the existing individual mission datasets: GOME solar irradiances are harmonised using a validated SCIAMACHY solar reference spectrum, solving the problem of the fast-changing etalon present in the original GOME Level 1b data; Reflectances for both GOME and SCIAMACHY are provided in the FDR product. GOME reflectances are harmonised to degradation-corrected SCIAMACHY values, using collocated data from the CEOS PIC sites; SCIAMACHY data are scaled to the lowest integration time within the spectral band using high-frequency PMD measurements from the same wavelength range. This simplifies the use of the SCIAMACHY spectra which were split in a complex cluster structure (with own integration time) in the original Level 1b data; The harmonization process applied mitigates the viewing angle dependency observed in the UV spectral region for GOME data; Uncertainties are provided. Each FDR product provides, within the same file, irradiance/reflectance data for UV-VIS-NIR special regions across all orbits on a single day, including therein information from the individual ERS-2 GOME and Envisat SCIAMACHY measurements. FDR has been generated in two formats: Level 1A and Level 1B targeting expert users and nominal applications respectively. The Level 1A [ATMOS__L1A] data include additional parameters such as harmonisation factors, PMD, and polarisation data extracted from the original mission Level 1 products. The ATMOS__L1A dataset is not part of the nominal dissemination to users. In case of specific requirements, please contact EOHelp. Please refer to the README file for essential guidance before using the data. All the new products are conveniently formatted in NetCDF. Free standard tools, such as Panoply, can be used to read NetCDF data. Panoply is sourced and updated by external entities. For further details, please consult our Terms and Conditions page. Uncertainty characterisation One of the main aspects of the project was the characterization of Level 1 uncertainties for both instruments, based on metrological best practices. The following documents are provided: General guidance on a metrological approach to Fundamental Data Records (FDR) Uncertainty Characterisation document Effect tables NetCDF files containing example uncertainty propagation analysis and spectral error correlation matrices for SCIAMACHY (Atlantic and Mauretania scene for 2003 and 2010) and GOME (Atlantic scene for 2003) reflectance_uncertainty_example_FDR4ATMOS_GOME.nc reflectance_uncertainty_example_FDR4ATMOS_SCIA.nc
ERS-1/2 SAR IM Medium Resolution L1 [SAR_IMM_1P]
This ERS Medium Resolution stripline product is generated from the Image Mode Level 0 Product. Stripline image products contain image data for an entire segment, up to a maximum size of 10 minutes per product for IM mode. The processor concatenates together several sub-images called "slices" that were processed separately on a dataset-by-dataset basis in order to form the entire stripline image. The product is processed to an approximately 150 m x 150 m resolution and has a radiometric resolution that is good enough for ice applications. This product has a lower spatial resolution than the SAR_IMP_1P and SAR_IMS_1P products. Product Characteristics: Pixel size: 5 m (ground range – across track) x 75 m (azimuth – along track) Scene area: 100 km (range) x at least 102.5 km Scene Size: 1300 pixels (range) x at least 1350 lines (azimuth) Pixel depth: 16 bits unsigned integer- Total product volume: at least 3.5 MB Projection: Ground-range Number of looks: 8 (azimuth) x 7 (range).
ERS-1/2 SAR IM Precision L1 [SAR_IMP_1P]
The SAR Precision product is a multi-look (speckle-reduced), ground range image acquired in Image Mode. This product type is most applicable to users interested in remote sensing applications, but is also suitable for calibration purposes. The products are calibrated and corrected for the SAR antenna pattern and range-spreading loss. Radar backscatter can be derived from the products for geophysical modelling, but no correction is applied for terrain-induced radiometric effects. The images are not geocoded, and terrain distortion (foreshortening and layover) has not been removed. The numbering sequence relates to the satellite position and therefore differs between Ascending and Descending scenes. Product characteristics: Pixel size: 12.5 m (range - across track) x 12.5 m (azimuth - along track) Scene area: 100 km (range) x at least 102.5 km (azimuth) Scene size: 8000 pixels range x at least 8200 lines (azimuth) Pixel depth: 16 bits unsigned integer Total product volume: 125 MB Projection: Ground-range Number of looks: 3.
ERS-1/2 SAR IM Single Look Complex L1 [SAR_IMS_1P]
The SAR SLC product is a single look complex acquired in Image Mode. It is a digital image, with slant range and phase preserved, generated from raw SAR data using up-to-date auxiliary parameters. The products are intended for use in SAR quality assessment, calibration and interferometric applications. A minimum number of corrections and interpolations are performed on the data. Absolute calibration parameters (when available) are provided in the product annotation. Product characteristics: Pixel size: 8 m (range - across track) x 4 m (azimuth - along track – varying slightly depending on acquisition Pulse Repetition Frequency) Scene area: 100 km (range) x at least 102.5 km (azimuth) Scene size: 5000 samples (range) x at least 30000 lines (azimuth) Pixel depth: 32 bits signed integer (16 bits I, 16 bits Q) Total product volume: 575 MB Projection: Slant range- Number of looks: 1.
ERS-1/2 SAR IM L0 [SAR_IM__0P]
This SAR Level 0 product is acquired in Image Mode. The products consist of the SAR telemetry data and are supplied as standard scenes. It also contains all the required auxiliary data necessary for data processing. The product serves two main purposes: For testing ERS SAR processors independently from the HDDR system For users interested in full SAR data processing. Product characteristics: Scene area: 100 km (range - across track) x full segment length (azimuth - along track) Scene size: 5616 samples (range) x full segment length (azimuth) Pixel depth: 10 bits signed integer (5 bits I, 5 bits Q) Projection: Slant range.