17 September 2018: Significant progress has been made in the last year, organizing the community and advocating for Passive Microwave (PMW) continuity. The SST-VC notes progress with two, complementary missions that if successfully put into operations will fill the looming gap in PMW imagery. One is the ESA Copernicus Imaging Microwave Radiometer (CIMR) (https://cimr.eu/). CIMR's focus on low frequency, high resolution (10 km real aperture at 6.9GHz and <5 km at 18.7 GHz) channels would result in a step-change in EO capability with potential to revolutionise SST and sea ice monitoring from space. While not yet a fully approved mission, CIMR is promising and is currently in Phase A/B1, with phase B2 in preparation. The second area of progress is from JAXA on the AMSR2 follow-on mission, AMSR3. AMSR3 entered the pre-project phase in September. AMSR3 will have almost the equivalent sensor specification in antenna size and channels as the current AMSR2 on board the GCOM-W satellite, except additional higher frequency channels (166, 183GHz) to improve solid precipitation retrievals and water vapor analysis in NWP will be included. Both AMSR3 and CIMR have proposed launches in the 2022-2025 timeframe. The two missions are highly complementary and would provide an unprecedented coverage and revisit of the global ocean and high latitude sea ice conditions.
In addition, the following excerpt from a draft CGMS report on PMW is included to further illustrate the successful cross-agency coordination on the need for PMW continuity and redundancy:
CGMS-46-EUMETSAT-WP-14 provided background information for the session on the potential gap in microwave observations, in particular for SST and ice monitoring. In 2017 CEOS SST-VC pointed to the risk in loss of low frequency Passive Micromave imager measurements which CEOS SIT confirmed in April 2018. Subsequently a Nature article and the EGU blog have discussed the issue with special focus on impact on SST and ice extent. In December 2017, ECMWF and ESA arranged a workshop on using low frequency passive microwave measurements in research and operational applications, and a dedicated AGU cryosphere session was held on the topic (with participation from operational space agencies). WGClimate also raised concerns at their latest meeting.
Since the SST-VC has successfully coordinated the agencies and community input on PMW, we recommend closing this action. The SST-VC will continue to monitor the situation, track progress, and raise any concerns through the CEOS and other venues.