Research on the Calculating Directly Water Vapor Value Using Zenith Tropospheric Delay Data

This paper compares and analyzes the change trend of zenith tropospheric delay (ZTD) and integrated water vapor (IWV) at BJFS, LHAS and WUHN stations in July 2002, and puts forward a new method which can calculate directly IWV using GPS ZTD without other transformations. The IWV calculated by the method is validated with the IWV computed by traditional method. The results show that the method is feasible