Microwave Radiometer Carried By Shenzhou IV Data Processing And Land Surface Parameters Retrieval

The multiple model microwave remote sensor is an important part of the payload carried by Shenzhou IV spacecraft launched on 30 December 2002 and is also China's first experimental microwave remote sensing system operating in space. The system includes three kinds of microwave remote sensors, namely microwave radiometer, radar altimeter and radar scatterometer .The radiometer instrument provides global passive microwave measurements of terrestrial, oceanic, and atmospheric variables for the investigation of water and energy cycles.Microwave radiometer observations are sensitive to soil moisture through the effect of moisture on the dielectric constant and hence emissivity of soil. Vegetation and roughness reduce the sensitivity of the microwave observations to soil moisture and theirs effects become more pronounced as the frequency increases; hence, low frequencies in the L-band range(l — 2GHz)are preferred for soil moisture sensing.But it was judged in the satellite radiometer designed stage that L band is not feasible yet now. C-band(4-6GHz) is chosen as the second best choice. The SZ-4 radiometer choose the C-band centered at 6.6GHz(with 400-MHz bandwidth) as its lowest frequency, which has been shown to be sensitive to soil moisture, but primarily in regions of low vegetation.The SZ-4 radiometer can be used to gain information about conditions of land, but in this flight, no field experiments about land surface soil moisture observations have been planned .So it is difficult to evaluation the capability of SZ-4 radiometer for land surface parameters retrieval without the common measurements from field and spacecraft sensor.The primary objective of the present study is to evaluate the performance of the SZ-4 microwave radiometer by using the brightness data to estimate the land surface parameters including soil moisture, soil temperature and vegetation optical depth. The thesis consists of a series of chapters.Chapter 1 provides a descriptive outline, general introduction to microwave remote sensing, and thesis objective and approach. Chapter 2 provides a background in passive microwave remote sensing of land surface parameters. Chapter 3 describes SZ-4 radiometer instrument...