TY - JOUR ID - 109639 TI - The Retrieval of Wet Refractivity Index by Tomography Using Spherical Cap Harmonics JO - Space Science and Technology JA - JSST LA - en SN - 2008-4560 AU - Dehvari, Masoud AU - Farzaneh, Saeed AU - Sharifi, Mohammad Ali AD - M.Sc., School of Surveying and Geomatics Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran AD - Associate Professor, School of Surveying and Geomatics Engineering, Faculty of Engineering, University of Tehran,, Tehran, Iran Y1 - 2022 PY - 2022 VL - 15 IS - English Special Issue SP - 15 EP - 24 KW - Empirical Orthogonal Functions KW - Legendre function KW - Radiosonde KW - numerical weather model KW - tropospheric wet delay DO - 10.30699/jsst.2022.1256 N2 - In this research, three-dimensional and four-dimensional tomography is used to demonstrate the distribution of wet refractivity index of the troposphere. In this model, spherical cap harmonics are used for the horizontal distribution of the wet refractivity index, and empirical orthogonal functions are used for the vertical distribution of the index. The region of study is in the west California State, and the wet refractivity index is retrieved from the wet tropospheric delay measurements. to validate the results, radiosonde profiles were compared to the tomographically retrieved profiles. The result shows that wet refractivity indices can be retrieved using functional models with RMSE about 2.4 ppm till 3.9 in four-dimension method. The comparisons show that the four-dimensional retrieved profiles shows improvement up to 34 and 42 percentage in mid-day tomography epochs compare to three-dimensional tomography results. Also it can be seen that in mid-night epochs three-dimensional tomography has higher accuracy compare to four-dimension method because of low variation of wet refractivity indices UR - https://jsst.ias.ir/article_109639.html L1 - https://jsst.ias.ir/article_109639_5306d4b19a1469bbfc1c7d45947a2bc3.pdf ER -