Atmospiieric Profiles from Radio Occultation Measurements of Gps Satellites

Atmospheric profiles can be retrieved with techniques utilizing measurements of the propagation delay of signals from Global Positioning System (GPS) satellites observed by one or more receivers in low earth orbit. The. observations are made in a limb-sounding geometry when the radio path between the transmitter and receiver passes through the atmosphere. The various componen~s of the microwave refractivity of the earth’s atmosphere are described and in particular the effect of liquid water suspended in the atmosphere is examined. We briefly describe the retrieval technique and the information it provides. We then discuss the impulse response of the retrieval technique and provide an intuitive description of the effect of horizontal structure on the retrieval process. We conclude with examples of the ability to separate temperature and water vapor densities in measurements made in the lower troposphere