Determination of Vertical Refractivity Structure from Ground-based GPS Observations

The primary scientific objective of this research is to develop GPS sounding techniques for ground based atmospheric refractivity sensing. Atmospheric profiling with GPS from space has been demonstrated (e.g. Rocken et al., 1997). Ground based receivers have been used to determine integrated atmospheric water vapor above a site, but profiling techniques with ground-based GPS observations are still under development (Anderson 1982, 1994). Ground based observations of GPS tropospheric signal delay and bending cannot be inverted to high-resolution atmospheric profiles comparable to radiosondes, but they provide direct measurements of microwave signal bending (Sokolovskiy et al., 2001) and coarse refractivity structure information (Lowry et al., 2001).