Atmospheric Humidity Sounding Using Differential Absorption Radar Near 183 GHz
Atmospheric Humidity Sounding Using Differential Absorption Radar Near 183 GHz
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DOI：
10.1109/lgrs.2017.2776078
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发表时间：
2018-02-01
影响因子：
4.8
通讯作者：
Brown, Andrew
中科院分区：
文献类型：
--
作者：
Cooper, Ken B.;Monje, Raquel Rodriguez;Brown, Andrew
研制了一种G波段可调谐调频连续波雷达系统，并首次用于差分吸收大气湿度测量。该雷达的发射机使用高功率处理GaAs肖特基二极管，在183 GHz附近的10 GHz带宽上产生15-23 dBm的功率。由于采用了高隔离度的圆极化天线，单基地雷达接收机在发射机工作时噪声系数仍保持在7 dB左右，天线增益为40 dB，可实现几百米范围内的高信噪比小雨探测。由于183-GHz水吸收线上翼的大气吸收具有很强的光谱依赖性，因此可以通过在距离和频率上对雨回波进行比值来获得绝对湿度的距离分辨测量。所获得的吸收测量结果与大气毫米波衰减模型一致，它们展示了一种提高云内湿度测量精度的新方法。
A tunable G-band frequency-modulated continuous-wave radar system has been developed and used to perform differential absorption atmospheric humidity measurements for the first time. The radar's transmitter uses high-power-handling GaAs Schottky diodes to generate between 15-23 dBm over a 10-GHz bandwidth near 183 GHz. By virtue of a high-isolation circular polarization duplexer, the monostatic radar's receiver maintains a noise figure of about 7 dB even while the transmitter is on. With an antenna gain of 40 dB, high-SNR detection of light rain is achieved out to several hundred meters distance. Owing to the strong spectral dependence of the atmospheric absorption over the upper flank of the 183-GHz water absorption line, range-resolved measurements of absolute humidity can be obtained by ratioing the rain echoes over both range and frequency. Absorption measurements obtained are consistent with models of atmospheric millimeter-wave attenuation, and they demonstrate a new method for improving the accuracy of humidity measurements inside of clouds.