{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,15]],"date-time":"2025-11-15T10:28:11Z","timestamp":1763202491864,"version":"build-2065373602"},"reference-count":57,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2021,6,21]],"date-time":"2021-06-21T00:00:00Z","timestamp":1624233600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Special Scientific Research Fund of Meteorological Public Welfare Profession of China","award":["GYHY201406012"],"award-info":[{"award-number":["GYHY201406012"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>A fast voxel traversal algorithm for ray tracing was applied to build a 4 \u00d7 4 \u00d7 20 tomography model using the observation data of 11 ground-based Global Navigation Satellite System (GNSS) meteorology (GNSS\/MET) stations in Hebei Province, China. The precipitation water vapor (PWV) observed at 05 a.m. (Universal Time Coordinated: UTC) on 10 December 2019, was used to reconstruct three-dimensional (3D) water vapor density fields over the test area. The tomographic results (GNSS_T) show that the water vapor density above this area is mainly below 25 g\/m3 and is concentrated between the first to the fourth layers. The vertical distribution conforms to the exponential characteristics, while the horizontal distribution shows a decreasing trend from southwest to northeast. In addition, the results of the 0.25\u00b0 grid dataset generated by the Global Forecast System (GFS) of the National Center for Environmental Forecasting (NCEP) (GFS_L) were interpolated to the height of the tomographic grid, which is in good agreement with the tomographic results. GFS_L is larger than GNSS_T on the first floor at the surface, with an average deviation of 0.19 g\/m3. In contrast, GFS_L from the second floor to the top of the model is smaller than GNSS_T, with the average deviations distributed between \u22120.08 and \u22120.15 g\/m3.<\/jats:p>","DOI":"10.3390\/rs13122422","type":"journal-article","created":{"date-parts":[[2021,6,21]],"date-time":"2021-06-21T13:29:58Z","timestamp":1624282198000},"page":"2422","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["A Case Study of the 3D Water Vapor Tomography Model Based on a Fast Voxel Traversal Algorithm for Ray Tracing"],"prefix":"10.3390","volume":"13","author":[{"given":"Heng","family":"Hu","sequence":"first","affiliation":[{"name":"Meteorological Observation Center of China Meteorological Administration, Beijing 100081, China"}]},{"given":"Min","family":"Liu","sequence":"additional","affiliation":[{"name":"Shanghai Meteorological Service, Shanghai 200030, China"}]},{"given":"Jiqin","family":"Zhong","sequence":"additional","affiliation":[{"name":"Institute of Urban Meteorology, CMA, Beijing 100081, China"}]},{"given":"Xin","family":"Deng","sequence":"additional","affiliation":[{"name":"National Meteorological Information Centre of China Meteorological Administration, Beijing 100081, China"}]},{"given":"Yunchang","family":"Cao","sequence":"additional","affiliation":[{"name":"Meteorological Observation Center of China Meteorological Administration, Beijing 100081, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9452-407X","authenticated-orcid":false,"given":"Peng","family":"Fang","sequence":"additional","affiliation":[{"name":"Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA"}]}],"member":"1968","published-online":{"date-parts":[[2021,6,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1029\/2000RS002353","article-title":"Validation of line-of-sight water vapor measurements with GPS","volume":"36","author":"Braun","year":"2001","journal-title":"Radio Sci."},{"key":"ref_2","first-page":"RG2001","article-title":"Tropospheric water vapor, convection, and climate","volume":"48","author":"Sherwood","year":"2010","journal-title":"Rev. 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