Multifrequency Imaging Microwave Radiometer Research Articles

A Study For Microwave Imaging Missions

In the field of scanning passive imagers TAS-I has a strong heritage that comes from many studies on MIMR (Multifrequency Imaging Microwave Radiometer), IGPM (Italian contribution to Global Precipitation Mission) and EGPM (European contribution to Global Precipitation Mission) and FLORAD [Marzano, 2002 and 2008] studies. Based on that heritage TAS has participated to the recently issued ESA ITT on Post-EPS microwave imager. Post-EPS is a programme addressing the need of continuing the EUMETSAT POLAR SYSTEM (EPS) in order to provide remote sensing observations for operational meteorology and climate monitoring. In the article an overview of the principle involved in a Microwave Radiometer Design Process taking as reference the trade-offs flow and philosophy approach pursued during the proposal for P-EPS MWI study is described.

Nonlinear statistical retrievals of ice content and rain rate from passive microwave observations of a simulated convective storm

A numerical simulator for analysis of multispectral passive microwave mapping and retrieval is described. This simulator allows evaluation and optimization of satellite-based cloud and precipitation parameter retrieval algorithms. It contains three major components: the forward radiative transfer model, the sensor observation model, and the parameter retrieval algorithm. Simulated spaceborne observations of an oceanic tropical squall sampled at five stages in time are demonstrated for a simplified version of the proposed Earth Observation System (EOS) Multifrequency Imaging Microwave Radiometer (MIMR). The simulator uses a nonlinear statistical retrieval algorithm consisting of a Karhunen-Loeve (KL) transform, a projection operator, a nonlinear inverse mapping and a linear minimum mean-square error estimator. Retrievals of rain rate and integrated ice content are performed for each evolutionary frame at both full spatial resolution (1.5 km) and the degraded spatial resolution of a MIMR-class system. Results are presented for both KL-based and brightness temperature-based retrieval algorithms. It is found that the KL-based algorithm has a reduced complexity and performs better than the brightness temperature-based algorithm for degraded resolution imagery, especially for rain rate retrievals. In addition, rain rate retrievals are more affected by low image resolution than are integrated ice content retrievals. Retrieval accuracy of both rain and integrated ice is also found to depend on the evolutionary stage of the storm. >

Development of geophysical retrieval algorithms for the MIMR

The feasibility of using spaceborne microwave radiometry to retrieve geophysical parameters is described. The study concentrates on the development of inversion techniques for multichannel spaceborne radiometers, especially the statistical inversion approach. The applications of the planned MIMR (Multi-Frequency Imaging Microwave Radiometer) instrument are discussed. The inversion algorithms used are conventional algorithms for different applications and the statistical inversion approach. Comparisons between results from different inversion algorithms are presented. The statistical inversion approach has been found to give promising parameter retrieval accuracies and has the potential to improve the operational use of passive spaceborne remote sensing. An analysis of the sensitivity of the radiometer apparent temperature to different geophysical parameters and the statistical behavior of the atmospheric transmissivity are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>