| Ground-based multichannel microwave radiometer(GMR)is a passive remote sensing instrument for atmosphere,it can be used to observe and retrieve the high time resolution profiles of temperature and humidity.At presently,the GMR has been widely used in atmospheric remote sensing.Although it is only used to observe and retrieve the temperature and humidity profiles,its value cannot be full play in other fields.Therefore,based on the traditional atmospheric observation,focusing on the characteristics of high sensitivity and the remote sensing application potential of the GMR,the expansion application theory and observation method were systematically studied from the aspects of observation platform,observation mode and observation target in this paper.The main contents and results are summarized as follows:(1)The mobile observation model of the GMR was designed in this paper.The constraint conditions between the technical performance of the instrument and the platform conditions were proposed,then the retrieve method of mobile observation based on reanalysis data was developed.After that,the mobile observation experiment of vehicle microwave radiometer was carried out under the environment of urban and complex terrain of Qinghai-Tibet Plateau.The results showed that the correlation was more than 0.97,and the average bias of temperatureis within 2?,water vapor density is around 0.5g/m~3,the relative humidity is 10%?18%.(2)A method of sloping downward periodic(such as 2 minutes each time)observing earth surface radiation was proposed by using the GMR,it can be used to retrieve the soil temperature and humidity.Thus,on the basis of upward observation function of the GMR for atmosphere,it had realized a radiometer serves dual purposes of application.For this purpose,this study improved and optimized the radiometer system workflow,realized the sloping downward observation mode,and evaluated the potential application and data retrieve principle in soil temperature and humidity.This result has scientific and technological support for the function expansion of the GMR for soil temperature and humidity observation.(3)The feasibility of using the GMR to observe solar microwave radiation was explored,the observation theories and methods of the solar radiation brightness temperature and the process of solar eclipse were improved by using the GMR,and the response of microwave radiometer to solar radiation was systematically analyzed.On the one hand,the research uses the sun as the radiation source to measure the antenna pattern,monitor the antenna pointing and evaluate the stability of the radiometer system,which provides a method for the automatic monitoring of the state of the microwave radiometer.On the other hand,the average solar radiation brightness temperature and the process of solar eclipse were observed by the GMR.The results showed that the solar TB measurements were 9950±334,10351±370,and 9217±375 K at 22.235,26.235,and 30.000 GHz.And Compared with previous studies,the average percentage deviations are 9.1%,5.3%,and 4.5%at three frequencies,respectively.In addition,two solar eclipses were observed by the GMR.The results showed that the microwave radiometer could accurately respond to the variation of solar radiation during the solar eclipse.The results provide theoretical and technical basis for further solar observation and application of microwave radiometer.(4)Based on the long-term observation of solar radiation by using the GMR,a new observation method of the earth orbit eccentricity by microwave radiometer was proposed.The result showed that the measured eccentricity was 0.016783 which agreed quite well with the value of 0.01672 in literature.Furthermore,the average variation percentages of both the Earth-Sun distance and the intensity of the incident solar radiation throughout the year were estimated to be 3.413%and 6.493%,respectively.It is proved that the GMR can be used to estimate the earth orbit eccentricity and variation of the Earth-Sun distance.This paper lays a foundation and it provides a new idea for the traditional atmospheric observation and application,earth surface environment and solar radiation observation. |
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