The microwave radiactivproperty of snow is studied using self-developed three band microwave radiometers. Experiments were carried out repeatedly from 1986 to 1989 in Northeast China The relation between brightness te...The microwave radiactivproperty of snow is studied using self-developed three band microwave radiometers. Experiments were carried out repeatedly from 1986 to 1989 in Northeast China The relation between brightness temperature and observation angle was obtained with both vertical and horizontal polarizations. The curves corresponding brightness temperature and snow depth were also drawn out for different frequency bands. The results demonstrate the application potential of the multifrequency microwave radiometer in this area.展开更多
The blackbody calibration targets applied for microwave radiometer＇s prelaunch calibration are optimized with its electromagnetic and thermal characteristics. Based on the method of emissivity optimization with radar...The blackbody calibration targets applied for microwave radiometer＇s prelaunch calibration are optimized with its electromagnetic and thermal characteristics. Based on the method of emissivity optimization with radar cross section （RCS） simulation and the method of subgrid finite difference time domain （FDTD）, the following design rules are summarized： that the round wedge is better than the square one, the best ratio from height to bottom radius is 4：1, for wide band calibration, the multilayer absorbing material coating is efficient to increase the emissivity, and the gradual thickness absorbing material coating is helpful to guarantee the uniform distribution of surface temperature even as it keeps a higher emissivity. Finally following the above conclusions, a new type of blackbody calibration target with the cellular array is preferred to improve the uniformity of polarization, which will increase the performance of the calibration targets further.展开更多
基金The Project supported by National National Science Foundation
文摘The microwave radiactivproperty of snow is studied using self-developed three band microwave radiometers. Experiments were carried out repeatedly from 1986 to 1989 in Northeast China The relation between brightness temperature and observation angle was obtained with both vertical and horizontal polarizations. The curves corresponding brightness temperature and snow depth were also drawn out for different frequency bands. The results demonstrate the application potential of the multifrequency microwave radiometer in this area.
基金supported by the National Key Laboratory of Metrology and Calibration Technologythe Second Academy Institute of China Aerospace Science & Industry Corp
文摘The blackbody calibration targets applied for microwave radiometer＇s prelaunch calibration are optimized with its electromagnetic and thermal characteristics. Based on the method of emissivity optimization with radar cross section （RCS） simulation and the method of subgrid finite difference time domain （FDTD）, the following design rules are summarized： that the round wedge is better than the square one, the best ratio from height to bottom radius is 4：1, for wide band calibration, the multilayer absorbing material coating is efficient to increase the emissivity, and the gradual thickness absorbing material coating is helpful to guarantee the uniform distribution of surface temperature even as it keeps a higher emissivity. Finally following the above conclusions, a new type of blackbody calibration target with the cellular array is preferred to improve the uniformity of polarization, which will increase the performance of the calibration targets further.
