From ATSRs into SLSTR: An Overview of the Evolving Science and Exploitation from Along-Track Scanning Instruments
Remedios, John; Llewellyn-Jones, David
University of Leicester, UNITED KINGDOM
Three Along-Track Scanning Radiometers (ATSRs) have flown on ESA missions providing a dataset of thermal radiances and shortwave infrared radiances spanning over 20 years. Surface temperatures, particularly those of the sea, have been a primary target and have been accurately derived with uncertainties on global monthly men sea surface temperatures (SSTs) of less than 0.2 K. In the later ATSRs, ATSR-2 and AATSR, visible channels were added and have widened the utility of ATSR data to aerosols and clouds with important climate applications.
In this paper, the chief highlights of the ATSR mission will be presented, covering successes ranging from highly accurate SST for climate and operational oceanography to fire detections for carbon cycle and land-atmosphere emission studies. High radiometric accuracy has been one of its hallmarks. The long-time series of data on SST, clouds/aerosols and fires have been taken up the by the ESA Climate Change Initiative (CCI programme), and are being complemented now by long-term time series of land surface temperature (LST), lake surface water temperature (LSWT) and surface reflectance. Other uses for ATSR include gas flare detection, snow detection, and monitoring of the South Atlantic Anomaly. In the last decade, improvement in the quality of the ATSR long-term series of data has been very strong, leading to both significant science and applications. This progress will be reviewed and future improvements highlighted.
The perspectives on the Earth provided by the ATSR instrument will be extended into the next era with the Sea and Land SurfaceTemperature Radiometer (SLSTR) on Sentinel-3. Although qualitatively similar to the ATSRs, the SLSTR instrument(s) also incorporates interesting differences because of the double backward-scanning mechanisms and wider swaths employed in both dual and nadir-views. This talk will consider the improved data sets that will, in principle, be obtainable from the SLSTR instrument through its expected products and offline scientific analyses. The discussion will conclude by considering the challenges faced in continuing ATSR long-term records with SLSTR, to provide consistent long-term data sets.