radar and radiothermal characterictics of soil
M. L. Grigoryan, A. K. Arakelyan
At present, radiophysical methods of sensing and corresponding microwave devices have wide application for solution of direct and inverse problems of the Earth surface and atmospheric remote sensing. For precise and unambiguous solution of bare and vegetated soils microwave remote sensing inverse problems it is necessary to improve radiative transfer models for soil and vegetation. For this purpose it is necessary and very significant to develop and to manufacture multi-frequency and multi-polarization complex of combined radar-radiometers at L-Ka-band of frequencies, suitable for short range remote sensing application and to perform field or quasi-field measurements under quasi-field and controlled conditions.
In this paper data of spatio-temporally collocated, microwave active-passive and polarization measurements of soil surface radar and radio thermal characteristics angular dependences are presented. The measurements were carried out for bare soil and for a soil covered by dry vegetation and by ash formed after arson of the vegetation cover. The results have been obtained during the measurements carried out in quasi-field conditions in the experimental site of ECOSERV Remote Observation Centre Co.Ltd. (ECOSERV ROC) built in Armenia under the framework of ISTC Projects A-872 and A-1524. The measurements were carried out by Ka-band (~37GHz), combined scatterometric-radiometric system ArtAr-37 developed and built by ECOSERV ROC under the framework of the above mentioned Projects. Structural and operational features of the utilized system and the whole measuring complex are considered too.
In the paper the curves of simultaneously mesured at 37GHz radar cross sections and brightness (antenna) temperatures angular dependences are presented, for semi-wet and wet soil surfaces covered wth wheat brairds, for the soil covered with dry and cut grass, and for the soil covered with the ash after arson of dry grass. Data of measurements of dry soil surface (covered by dry cut grass) radar cross sections and brightness (antenna) temperatures at 300 incidence angle are presented too, for smock, fire, smolder and ash situations, measured respectively at “vv” (for a radar) and “v” (for a radiometer) polarizations. For comparison, data of measurements of clear air (sky) brightness temperatures at “v” and “h” polarizations are presented too, measured at 100 and 300 nadir angles of sensing.