In the frame of the Project multi-sensor approach for Polar Low study is going to be developed, with the strongest emphasizing upon the passive microwave data usage. Most available data will be used: Envisat ASAR for high resolution wind speed retrievals using existing CMOD-4 model, QuikSCAT low resolution wind speed additional data, Terra and Aqua MODIS, NOAA AVHRR data for studying Polar Low cloud structure, DMSP SSM/I, Aqua AMSR-E, NOAA AMSU-B for various geophysical parameter estimation, radiosonde re ports and surface weather maps as supplementary data. A radiative-transport model accounting for the emitted and scattered radiation from cloudy and precipitating Atmosphere-Ocean System is going to be developed to calculate the brightness temperatures of functioning satellite passive microwave instruments (SSM/I, AMSR-E, AMSU), using collected in-situ data and modeled cloud data. The inversion algorithms (NN-based) for ice water path and precipitation rate retrievals, using modeled brightness temperature s will be developed. The package of the algorithms for total atmospheric water vapour, total cloud liquid water, ice water path and precipitation rate estimation from satellite passive microwave data is going to be set up to be implemented for the Polar L ow cases. Several Polar Lows will be investigated using collected satellite and in-situ data to obtain related quantitative information and validate the developed methodological approach.