{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T13:39:08Z","timestamp":1774273148369,"version":"3.50.1"},"reference-count":44,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2021,7,28]],"date-time":"2021-07-28T00:00:00Z","timestamp":1627430400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Ground-based multichannel microwave radiometers (GMRs) can observe the atmospheric microwave radiation brightness temperature at K-bands and V-bands and provide atmospheric temperature and humidity profiles with a relatively high temporal resolution. Currently, microwave radiometers are operated in many countries to observe the atmospheric temperature and humidity profiles. However, a theoretical analysis showed that a radiometer can be used to observe solar radiation. In this work, we improved the control algorithm and software of the antenna servo control system of the GMR so that it could track and observe the sun and we use this upgraded GMR to observe solar microwave radiation. During the observation, the GMR accurately tracked the sun and responded to the variation in solar radiation. Furthermore, we studied the feasibility for application of the GMR to measure the absolute brightness temperature (TB) of the sun. The results from the solar observation data at 22.235, 26.235, and 30.000 GHz showed that the GMR could accurately measure the TB of the sun. The derived solar TB measurements were 9950 \u00b1 334, 10,351 \u00b1 370, and 9217 \u00b1 375 K at three frequencies. In a comparison with previous studies, we obtained average percentage deviations of 9.1%, 5.3%, and 4.5% at 22.235, 26.235, and 30.0 GHz, respectively. The results demonstrated that the TB of the sun retrieved from the GMR agreed well with the previous results in the literature. In addition, we also found that the GMR responded to the variation in sunspots and a positive relationship existed between the solar TB and the sunspot number. According to these results, it was demonstrated that the solar observation technique can broaden the field usage of GMR.<\/jats:p>","DOI":"10.3390\/rs13152968","type":"journal-article","created":{"date-parts":[[2021,7,28]],"date-time":"2021-07-28T21:21:04Z","timestamp":1627507264000},"page":"2968","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Measurement of Solar Absolute Brightness Temperature Using a Ground-Based Multichannel Microwave Radiometer"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4261-8282","authenticated-orcid":false,"given":"Lianfa","family":"Lei","sequence":"first","affiliation":[{"name":"Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, CMA Key Laboratory of Aerosol-Cloud-Precipitation, Nanjing University of Information Science & Technology, Nanjing 210044, China"},{"name":"School of Atmospheric Physics, Nanjing University of Information Science & Technology, Nanjing 210044, China"},{"name":"North Sky-Dome Information Technology (Xi\u2019an) Co., Ltd., Xi\u2019an 710100, China"},{"name":"Xi\u2019an Electronic Engineering Research Institute, Xi\u2019an 710100, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9664-3881","authenticated-orcid":false,"given":"Zhenhui","family":"Wang","sequence":"additional","affiliation":[{"name":"Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, CMA Key Laboratory of Aerosol-Cloud-Precipitation, Nanjing University of Information Science & Technology, Nanjing 210044, China"},{"name":"School of Atmospheric Physics, Nanjing University of Information Science & Technology, Nanjing 210044, China"}]},{"given":"Yingying","family":"Ma","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing (LIESMARS), Wuhan University, Wuhan 430074, China"}]},{"given":"Lei","family":"Zhu","sequence":"additional","affiliation":[{"name":"North Sky-Dome Information Technology (Xi\u2019an) Co., Ltd., Xi\u2019an 710100, China"},{"name":"Xi\u2019an Electronic Engineering Research Institute, Xi\u2019an 710100, China"}]},{"given":"Jiang","family":"Qin","sequence":"additional","affiliation":[{"name":"North Sky-Dome Information Technology (Xi\u2019an) Co., Ltd., Xi\u2019an 710100, China"},{"name":"Xi\u2019an Electronic Engineering Research Institute, Xi\u2019an 710100, China"}]},{"given":"Rui","family":"Chen","sequence":"additional","affiliation":[{"name":"North Sky-Dome Information Technology (Xi\u2019an) Co., Ltd., Xi\u2019an 710100, China"},{"name":"Xi\u2019an Electronic Engineering Research Institute, Xi\u2019an 710100, China"}]},{"given":"Jianping","family":"Lu","sequence":"additional","affiliation":[{"name":"North Sky-Dome Information Technology (Xi\u2019an) Co., Ltd., Xi\u2019an 710100, China"},{"name":"Xi\u2019an Electronic Engineering Research Institute, Xi\u2019an 710100, China"}]}],"member":"1968","published-online":{"date-parts":[[2021,7,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3134","DOI":"10.1109\/JSTARS.2016.2633439","article-title":"Retrieval of Sun Brightness Temperature and Precipitating Cloud Extinction Using Ground-Based Sun-Tracking Microwave Radiometry","volume":"10","author":"Mattioli","year":"2016","journal-title":"IEEE J. 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