The Copernicus Imaging Microwave Radiometer (CIMR) Mission is one of the six Copernicus HPCM (High Priority Candidate Missions), an Earth monitoring initiative led by the European Union (EU) and carried out in partnership with the EU Member States and the European Space Agency (ESA). The primary objectives of CIMR are the estimate in non-precipitating atmosphere of the Sea Ice Concentration (SIC) and Sea Ice Extent (SIE) with a spatial resolution <= 5 km and an uncertainty <=5%, and of the Sea Surface Temperature (SST) with a spatial resolution <= 15 km and an uncertainty <= 0.2 K. Special attention is given to the polar regions with the request of sub-daily revisit and "no hole at the Pole" spatial coverage. These objectives imply high accuracy measurements that translate in a required maximum brightness temperature (TB) error, i.e. radiometer noise and contamination error, in presence of radiometric discontinuities, of 0.5 K at a distance to the discontinuity equal to the spatial resolution. These and other driving factors led to the definition of a conical scanning radiometer with a rotating antenna assembly - composed of a reflector and a feed cluster - operating from L to Ka band in dual polarization. To fulfill the required coverage and spatial resolution within the applicable mass and volume constraints, the baseline solution foresees an unfurlable mesh reflector with a diameter of about 7m, whose major impairments are the gain reduction and the occurrence of the grating lobe effects in the radiation pattern. This disturbance to the measurements increases with increasing frequency and proper countermeasures have to be developed.
Multi-channel radiometric correction of the TOA brightness temperature for the effects of the mesh reflector
M Brogioni;G Addamo;AV Bosisio;O A Peverini;GVirone;
2020
Abstract
The Copernicus Imaging Microwave Radiometer (CIMR) Mission is one of the six Copernicus HPCM (High Priority Candidate Missions), an Earth monitoring initiative led by the European Union (EU) and carried out in partnership with the EU Member States and the European Space Agency (ESA). The primary objectives of CIMR are the estimate in non-precipitating atmosphere of the Sea Ice Concentration (SIC) and Sea Ice Extent (SIE) with a spatial resolution <= 5 km and an uncertainty <=5%, and of the Sea Surface Temperature (SST) with a spatial resolution <= 15 km and an uncertainty <= 0.2 K. Special attention is given to the polar regions with the request of sub-daily revisit and "no hole at the Pole" spatial coverage. These objectives imply high accuracy measurements that translate in a required maximum brightness temperature (TB) error, i.e. radiometer noise and contamination error, in presence of radiometric discontinuities, of 0.5 K at a distance to the discontinuity equal to the spatial resolution. These and other driving factors led to the definition of a conical scanning radiometer with a rotating antenna assembly - composed of a reflector and a feed cluster - operating from L to Ka band in dual polarization. To fulfill the required coverage and spatial resolution within the applicable mass and volume constraints, the baseline solution foresees an unfurlable mesh reflector with a diameter of about 7m, whose major impairments are the gain reduction and the occurrence of the grating lobe effects in the radiation pattern. This disturbance to the measurements increases with increasing frequency and proper countermeasures have to be developed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
