Tropospheric Water Vapor from LEO-LEO Occultation: Estimation by Differential Attenuation Measurements near 20 GHz

Abstract

A differential measurement concept is presented for retrieving the totalcontent of water vapor (Iwv, Integrated water vapor) along thepropagation path between two counter-rotating Low Earth Orbiting (LEO)satellites. This approach, referred to as DSA (Differential SpectralAttenuation) method, is based on the simultaneous measurement of thetotal attenuation at two relatively close frequencies in the K band, andon the estimate of a ``spectral sensitivity parameter{''} that is highlycorrelated to the Iwv content of the LEO-LEO link in the lowtroposphere. The DSA approach has the potential to overcome allspectrally ``flat{''} and spectrally correlated phenomena, includingatmospheric scintillation.