Spatio-temporal Fluctuations in Downwelling K-band Radiation of Atmosphere in the Presence of Clouds

Abstract

Results of atmospheric downwelling radiation brightness temperature spectral measurements in the band of water vapor resonant absorption near 22.235 GHz line are considered. The experiment has been going on for over four years. Ground-based observations have been carrying out by means of special multichannel microwave radiometer-spectrometer with improved fluctuation sensitivity and high temperature stability of gain coefficient. Two meteostations located nearby have been registering near-surface meteorological parameters change in addition to radiometric data. All the data obtained have been properly calibrated and divided by seasons. A part of data have been categorized by cloud species observed by video recordings. Atmospheric moisture content parameters (total water vapor mass and cloud liquid water content) have been retrieved using multi-frequency radiometric method. Kolmogorov’s structural functions for brightness temperatures at different frequencies and structural functions of moisture content parameters have been evaluated for a wide range of temporal intervals. The square root of structural function for a parameter is taken as a native measure of the parameter’s fluctuation intensity in this work.