CIMR compared to other PMRs: Channels and Spatial resolution
figureposted on 10.09.2019, 07:11 by Thomas Lavergne
The diagram illustrates the frequency channels of the candidate Copernicus Imaging Microwave Radiometer (CIMR) mission, and their targeted spatial resolutions. CIMR is also compared to two other similar Passive Microwave Radiometers (PMR): the Japanese AMSR2 in orbit since 2012, and the MWI to fly on-board the European EPS-SG satellites from ~2023 (MWI-SG).
CIMR is a polarized multi-frequency, conically scanning PMR, under study for the Expansion phase of the EU Copernicus Space Component. It is an advanced PMR that will bring further the operational monitoring capabilities of the polar regions, including the Arctic and adjacent seas. The primary objectives of CIMR are all-weather, high-resolution, high-accuracy, sub-daily observations of sea-ice concentration (SIC), and sea-surface temperature (SST).
On the left hand side, the ellipses illustrate the Instantaneous Field-Of-Views (iFOVs) at the different frequencies. Each ellipse corresponds to the footprint of a specific frequency channels, for a given instrument, and is an indication of the spatial resolution achieved.
It appears clearly that CIMR aims at a much improved spatial resolution than the AMSR series, in a largely overlapping range of frequencies (C-band to Ka-band). The W-band (near 90GHz) is not selected for CIMR. L-band (~1.4GHz) on board CIMR will continue the heritage of ESA SMOS and NASA SMAP. MWI-SG lacks the lower frequency channels (L-, C- and X-band) and generally has too coarse resolution for ocean and sea-ice operational applications at the horizon 2025.
On the right hand side, the discs illustrate the size of the antenna reflectors of each instrument. The bigger the antenna, the better the spatial resolution at a given frequency. Small antennas (MWI-SG, AMSR2) are solid dishes, while larger ones are meshes. The observation zenith angles (oza) theta are also reported. The larger oza of CIMR yields wider swaths, and enables coverage of the whole polar region every day (noticeably: no polar observation hole).
It is underlined that the CIMR concept is under development for EU, under the lead of ESA. The values used here are realistic, but not final.
For more information, see https://cimr.eu and #CIMReu on Twitter.