Tropospheric refractivity profile estimation using ground-based GPS

Measurements of phase delay form Ground-based GPS are traditionally used to derive the quantity of water vapor content. New techniques have been developed to retrieve refractivity profile using single mountain-based or general ground-based GPS observations recently. These developing techniques of obtaining tropospheric refractivity profile are introduced in the paper. Results comparing refractivity profiles retrieved by single general ground-based GPS and the Hopfield model are illustrated, which demonstrate ground-based GPS method has a better agreement with radiosonde profiles.