Vol. 11, no.1, 2019


Liudmila N. Zakharova, Alexander I. Zakharov
Kotelnikov Institute of Radioengineering and Electronics of RAS, Fryazino branch, http://fire.relarn.ru
Fryazino 141190, Moscow region, Russian Federation

Received 02.04.2019, accepted 17.04.2019
Abstract. In our paper Transbaikalian test sites were used to demonstrate the dependence of the vegetation covers radiophysical properties from environmental conditions, and air temperature first of all. The data of Japanese spaceborne polarimetric radar PALSAR acquired at various combinations of signal polarization on receive/transmit over several years were used to measure scattering properties of underlying covers at 8 test sites and to estimate input of various scattering mechanisms in radar signal backscatter. It was discovered that at low negative temperatures in winter the normalized radar cross-section level of vegetation covers decreases rapidly for all the signal polarization combinations. The greatest fall, up to 12 dB, is observed at cross polarization, and it is about 7-8 dB for copolarized signals. Polarimetric decomposition of scattering matrix shows the specificity of the scattering mechanisms temporal behavior depending on the air temperature. If surface scattering with low entropy is typical for vegetation-free soils all the year around, the dipole scattering mechanism of forests in summer is almost completely replaced by the class of surface scattering with moderate entropy in winter. Such a specificity of annual behavior of the sounding media scattering properties may affect the efficiency of automated methods of the underlying covers classification and an accuracy of their biophysical characteristics measurements.

Keywords: synthetic aperture radar, normalized radar cross-section, polarimetric decompositions, vegetation classification

UDC 528.8.044.2, 537.871.5

RENSIT, 2019, 11(1):49-56 DOI: 10.17725/rensit.2019.11.049

Full-text electronic version of this article - web site http://en.rensit.ru/vypuski/article/270/11(1)49-56e.pdf