Simulation And Wind Field Inversion Analysis Of Spaceborne Full Polarization Microwave Scatterometer System

Sea surface wind is an important dynamic parameter on the upper ocean system.The microwave scatterometer is currently the main spaceborne sensor capable of acquiring large-area,high-precision,and high-resolution global ocean surface wind field data in a short period of time.The existing operational satellite-borne microwave scattermeter uses the co-polarization mode,and the wind vector of the sea surface is retrieved by the observation of the back scattering coefficient(,)of the sea surface.However,the disadvantage of co-polarization scatterometer is that the wind direction may appear ambiguity when the wind field is retrieved.The full-polarization microwave scatterometer increases the measurement of the cross-polarization backscattering coefficient,and calculates the correlation coefficient of the co-polarization and cross-polarization backscattering coefficients—correlated scattering coefficients(,)to reduce the probability of occurrence of ambiguous solutions,thereby greatly improving the retrieval accuracy of the sea surface wind field.The fully polarimetric scatterometer has become an important development direction for future scatterometers,and the full-polarization microwave scatterometer simulation is an important research method before the sensor is manufactured.In this paper,the disadvantages of existing co-polarized microwave scatterometers in wind field measurement are firstly discussed.The basic principles of satellite-borne microwave scatterometers and related mathematical models are reviewed.According to the measurement principle of satellite-borne microwave scatterometers,the accuracy of radiation measurement is selected as the measurement of the accuracy of the system simulation model of scatterometer.The simulation process of the fully polarized microwave scatterometer system was established.In the simulation process,the simulation of the relevant scattering coefficients was derived,and the wind field retrieval method used in the fully polarized microwave scattering meter system was discussed.Based on the above research work,the system simulation and wind field retrieval analysis for our new generation HY-2 full-polarimetry scatterometer has been carried out.A simulation model for the spaceborne full-polarization microwave scatterometer system was established,which is based on the original mechanism of the HY2-SCAT scatterometer,the measurement of the cross-polarization scattering coefficient was increased,and the HY2-SCAT scatterometer geometry observation parameters was used.The results of sea surface wind field retrieved from the same polarimetric and fully polarimetric microwave scatterometer system are compared with each other and analyzed under the condition of different instrument measurement accuracy and noise level.The ability of retrieval of sea surface wind field by fully-polarized microwave scatterometer system was evaluated.The simulation results show that the fully-polarized microwave scatterometer has a better sea surface wind field retrieval performance than a co-polarized microwave scatterometer.The performance of the sea surface wind field is improved significantly at the low and middle wind speeds.The improvement is mainly manifested in the sea surface wind direction retrieval results.By comparing with the results of the co-polarization simulation,the result of full-polarity wind direction can be improved by more than 10°,but the improvement of wind speed retrieval accuracy is not obvious.