Atmospheric Humidity Sounding Using Differential Absorption Radar Near 183 GHz

作者：Cooper Ken B; Monje Raquel Rodriguez; Millan Luis; Lebsock Matthew; Tanelli Simone; Siles Jose V; Lee Choonsup; Brown Andrew

来源：IEEE Geoscience and Remote Sensing Letters, 2018, 15(2): 163-167.

DOI：10.1109/LGRS.2017.2776078

• Clouds
• humidity measurement
• millimeter-wave radar

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.

• 出版日期2018-2