|MEASUREMENTS AND ANALYSES OF MICROWAVE SCATTERING OF THE WIND SPEEDS ON SEA SURFACE
PANG Ai-Mei, SUN Yuan-Fu
First Institute of Oceanography,State Oceanic Administration
|The microwave scattering properties of sea surface were measured with a microwave scatterometer on the platform in a sea and an airplane.The measured data were processed and analyzed with statistical and analytical methods.The Model RS-2 scatterometer with a frequency of 10.0GHz was used on the sea platform,and the Model LS-JX scatterometer with the 9.7GHz frequency was used in the air-
plane.In the procedure of scattering properties, the marine environment parameters of wind speed, and direction,wave height,and direction,and sea surface temperature etc.were measured synchronously.At the same time,the changes in the antenna incident angle,polarized properties and the angles between the incident direction of scatterometer beam and wind direction were measured.The relationship of the microwave backscattering coefficients (σ°)with wind speeds was examined,and the changes of incident angles, polarized and the included angles between the incident direction of scatterometer beam and wind direction to the effects of backscattering coefficients (σ°) were examined.The results show that there are linear relationships between the measured σ°values and sea surface wind speeds, with the measured σ° values increasing with an increase in wind speeds; there are close relationships between the measuredσ°values and the antenna incident angles of the scatterometer, and the measured σ°values decrease with the increase in the antenna incident angles. The measured σ°values show periodic variations with the angles between the incident direction of scatterometer beam and wind direction with changes between 0°—360°.There is a relationship between the measured σ°values and the polarized properties of the scatterometer antenna.The measuredσ°values of vertical polarization are larger than the measured σ°values of horizontal polarization.At the same time, and in combination with Pillips Model of the microwave scattering measurement algorithm on sea surface, the relationship of the measured values and calculated values were analyzed comparably, with the results being highly similar.
|Key words: Sea surface wind speed, Phillips Model, Measurements and analyses