The Data Product Quality Reports summarise the assessment of the altimetry mission, split per instrument or thematic topic: SRAL, MWR, Ocean Validation, Winds & Waves, and Land & Sea Ice.
Each report covers a cyclic period of 27 days and the details of each Sentinel-3 orbital cycle are available. As of 16 December 2018, the reports also contain the details of Sentinel-3B cycles. In the tables, the Sentinel-3A and -3B cycle numbers are shown on the left and right, respectively:
The SRAL instrumental calibration is assessed during the mission. Several parameters are monitored and analysed in detail in order to characterise the altimeter performance along the mission lifetime. Two main groups of calibration parameters are monitored: the first is derived from the Point Target Response (PTR) calibration (CAL-1 mode and product) while the second is related to the Instrument Transfer Function (CAL-2). Additionally, for SAR mode, the two intra-burst corrections are monitored: power and phase progression within a burst. Other HKTM parameters are also monitored.
The MWR instrument is monitored through two different time scales. First, the short term monitoring focuses on the internal calibration and brightness temperatures based on NRT products generated at the Svalbard core ground station (SVL) and on the geophysical products based on STC (Short-Time Critical) since cycle 13. Secondly, the long term monitoring focuses on the internal calibration based on NTC (Non-Time Critical) products and on the vicarious calibration targets and geophysical parameters. The geophysical long term monitoring will be completed as soon as a sufficient amount of data is available.
The Ocean Validation reports summarise validation results obtained from SRAL/Sentinel-3 STC Marine Level 2 products processed by the Marine Centre by monitoring the following parameters: Sea Level Anomaly (SLA), Significant Wave Height, Backscattering Coefficient, and Altimeter Wind Speed.
The Winds and Waves reports address the quality of wind and wave observations from the radar altimeter SRAL on-board Sentinel-3. The product under consideration is the Level 2 Marine Ocean and Sea Ice Areas (SRAL-L2MA) also referred to as S3A_SR_2_WAT that is nominally distributed in Near Real Time (NRT). Radar backscatter (sigma0), surface Wind Speed (WS) and Significant Wave Height (SWH) from the S3A_SR_2_WAT product are monitored and validated using the procedure which was successfully used for the validation of the equivalent products from earlier altimeters. Model equivalent products from the ECMWF Integrated Forecasting System (IFS) and in-situ measurements available in NRT trough the Global Telecommunication System (GTS) are used for the validation.
The Land and Sea Ice reports address the performance and data quality of the Sentinel-3A SRAL Level 2 data products over land ice (polar ice sheets, ice shelves, and ice caps) and sea ice surfaces. For land ice, the SR_2_LAN Level 2 NTC (Non Time Critical) products which contain the final orbit and geophysical corrections are assessed. For sea ice, we assess the SR_2_WAT Marine Level 2 STC (Slow Time Critical) products, produced by the S3 Marine Centre. The reports focus on data quality assessment and on any changes likely to impact data quality at any level, from instrument status to software configuration.