王婉,雷恒池,聂皓浩,王兆宇,郭晓军. 2021. 基于机载微波辐射计探测大气水汽通道饱和问题研究[J]. 气象学报, (0):-, doi:10.11676/qxxb2021.027
基于机载微波辐射计探测大气水汽通道饱和问题研究
Study on Channels Saturation of Precipitable Water Vapor Detection Based on Airborne Microwave Radiometer
投稿时间:2020-10-29  修订日期:2021-03-01
DOI:10.11676/qxxb2021.027
中文关键词:  微波辐射计,大气水汽,通道饱和,阈值
英文关键词:Microwave  radiometer, precipitable  water vapor, channel  saturation, threshold
基金项目:市自然科学基金
作者单位邮编
王婉 天津市人工影响天气办公室 300074
雷恒池 中国科学院大气物理研究所云降水物理与强风暴重点实验室 100029
聂皓浩 天津市人工影响天气办公室 300074
王兆宇 天津市人工影响天气办公室 300074
郭晓军 天津市人工影响天气办公室 300074
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中文摘要:
      183.31GHz微波辐射计在探测低含量水汽时具有优势,但也存在通道饱和问题,定量研究该问题对明确该类型仪器探测水汽能力和适用范围具有重要意义。本文基于天津市人工影响天气办公室增雨飞机运-12搭载的183.31GHz机载微波辐射计GVR(G-band water Vapor Radiometer,文中简称GVR),在前期研究工作基础上,对该辐射计四个探测通道进行饱和问题研究,定量计算其饱和阈值及探测灵敏度,分析各通道水汽探测能力及适用范围,结果表明:机载微波辐射计四个探测通道水汽探测灵敏度及饱和阈值与观测高度有关,当水汽含量较小时,通道1(183±1GHz)观测高度越高灵敏度越高,通道3(183±7GHz)和通道4(183±14GHz)观测高度越高灵敏度越低,通道2(183±3GHz)灵敏度几乎不受观测高度影响,通道1和通道4观测高度越高积分水汽探测饱和阈值越小,观测高度越低,饱和阈值越大,通道2和通道3饱和阈值几乎不受观测高度影响;晴空条件下选择水汽探测能力最强的单通道对积分水汽含量进行反演,当积分水汽含量处于0~1.3mm、1.3~4mm、4~9.8mm时,分别选择通道1、通道2、通道3作为反演通道,不同观测高度的积分水汽含量反演均适用;云的发射作用使辐射计各通道亮温增加,亮温增加幅度与云水含量、云与观测高度之间距离及云厚有关,云液态水含量越大,各通道水汽探测灵敏度及饱和阈值越小;云天条件下选择水汽探测能力最强的双通道对积分水汽含量进行反演,以积分液态水路径区间来选择合适的水汽探测通道,液态水含量越大,积分水汽可探测范围越小。
英文摘要:
      Microwave radiometers of 183.31 GHz have advantages in detecting low water vapor content, but there"s channel saturation problem, Quantitative study of this problem is very important to clarify the water vapor detection ability and application range of this type of instrument. Based on the airborne microwave radiometer carried by precipitation enhancement aircraft Y-12, this paper will calculate saturation threshold of the four detection channels and detection sensitivity and further then analysis of water vapor detection capability and application range of each channel. The results show that:: The water vapor detection sensitivity and saturation threshold of four channels are related to the observation height. When the water vapor content is low,the sensitivity of channel 1(183±1GHz) increases with the increase of observation height,the sensitivity of channel 3 (183±7GHz) and channel 4 (183±14GHz) decreases with the increase of observation height,the sensitivity of channel 2 (183±3GHz) is almost unaffected by observation height. The higher the observation height of channel 1 and channel 4, the smaller the saturation threshold of integrated water vapor detection, the lower the observation height, the greater the saturation threshold. channel 2 and channel 3 saturation thresholds are almost unaffected by observation height. Selecting the single channel with the strongest water vapor detection ability to retrieve the integral water vapor content under the condition of clear sky. When the integral water vapor content is during 0~1.3 mm,1.3~4 mm,4~9.8mm, channel 1, channel 2, channel 3 are selected as inversion channels Correspondingly. The cloud emission increases the bright temperature of radiometer each channel. The increase range of bright temperature is related to cloud water content, distance between cloud and observation height and cloud thickness.The greater the cloud liquid water content, The smaller the water vapor detection sensitivity and saturation threshold. Inversing the Integral water vapor content is retrieved by selecting two channels with the strongest water vapor detection ability, to select the appropriate water vapor detection channel by integrating the liquid water path interval.The greater the content of liquid water, the smaller the detectable range of integral water vapor.
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