Intercalibration of AMSR2 sea ice concentration estimates using limited AMSR-E information

Abstract:

The Advanced Microwave Scanning Radiometer 2 (AMSR2) was launched in May 2012 on the JAXA GCOM-W platform as a follow-on to the NASA/JAXA AMSR-E sensor on the NASA Aqua sensor. Unfortunately, AMSR-E data collection ended in October 2011 due to a problem with the rotation of the antenna. After investigation, it was deemed safe to turn the sensor back on, but at a rotation rate of only 2 rpm. This yielded only limited data compared to the nominal operational rate of 40 rpm. However, though degraded, the AMSR-E sensor was able to provide valuable (albeit limited) overlap data with which to intercalibrate AMSR2. For sea ice, AMSR2 brightness temperatures were regressed with AMSR-E at overlap locations for January to December 2013. The full year of overlap allows investigation of any potential seasonal effects, which may be particularly relevant in high latitude regions. Based on the regressions, the AMSR2 brightness temperatures were adjusted to be consistent with the NASA Team 2 algorithm parameters for AMSR-E. This will allow a consistent climate record of enhanced sea ice concentration information from 2002 through the present and into the future. While not as long as other passive microwave sea ice time series from the SMMR-SSM/I-SSMIS record, the higher spatial resolution and other improvements in the AMSR sensors, along with an enhanced algorithm provide considerably improved sea ice fields that yield greater accuracy and improved details within the ice cover.