Construction of 4D Water Vapor Field with Ground-based GPS Observations in Hong Kong Region

摘要

A great progress has been made in the precise determination of integrated precipitable water vapor (PWV) using GPS observations. PWV, however, contains less information about the vertical distribution of water vapor at a site. Our study is to use slant water vapor (SWV), which is the amount of water vapor between a surface receiver and each of GPS satellites in view, to determine spatial variation of water vapor in the atmosphere. SWV is, however, much more difficult to accurately measure than PWV because it does not benefit from averaging and thus strongly affected by various sources of errors in GPS measurements. This paper presents our experience in the precise and real time determination of SWVs and an attempt to construct the vertical profile of water vapor distribution with the tomography technique. Our study used the data from Hong Kong active GPS network of 13 stations.