INSTRUMENT PERFORMANCE AND CALIBRATION OF AMSR-E AND AMSR2

The Global Change Observation Mission (GCOM) consists of two satellite observing systems and three generations to achieve global, comprehensive, and long-term Earth monitoring. The first satellite of the GCOM-W (Water) series will be GCOM-W1 with the Advanced Microwave Scanning Radiometer-2 (AMSR2) onboard. AMSR2 is a successor of AMSR on the Advanced Earth Observing Satellite-II (ADEOS-II) and AMSR for EOS (AMSR-E) on NASA's Aqua satellite. Basic performance of AMSR2 will be similar to that of AMSR-E based on the minimum requirement of data continuity of AMSR-E, with several enhancements including larger main reflector (2.0 m), additional channels in C-band receiver, and improved calibration system. AMSR-E was launched in 2002 and is still gathering global brightness temperatures for more than eight years beyond its scheduled operational period of three years. Despite the warm-load calibration issue, the instrument indicates good performance in long-term stability. Based on the AMSR and AMSR-E experience, several design changes were made for the AMSR2 warm load, including changes in thermal stabilization and solar light shielding. Pre-launch testing is being performed, such as antenna pattern and detector nonlinearity measurements. The testing results will be reflected in sensor calibration model. After the launch, a deep-space calibration maneuver will be performed just one time during the initial checkout period to check consistency between main reflector and cold sky mirror, as well as to see scan biases for cold brightness temperatures. Further post-launch calibration activities will be performed, including cross calibration among similar microwave radiometers. Since GCOM-W1 will join the A-Train constellation, cross calibration between AMSR-E and AMSR2 will be very simple and thus accurate. Continuation from AMSR-E to AMSR2 with the consistent cross calibration will enable us to construct over 20-years data set of unique geophysical parameters including all-weather sea surface temperatures and soil moisture content. Current target launch year of GCOM-W1 is in Japanese fiscal year 2011.