Measurement of atmospheric refractivity using signals of opportunity

High-resolution numerical weather models require fine-scale (1-5 km) measurements of moisture fields over large areas (>;20,000 km²). Existing techniques such as GPS are not able to meet these requirements. This paper discusses the feasibility of a novel method for measuring atmospheric refractivity by the opportunistic reception and processing of digital radio and television signals. This technique is step towards the realization of a wide-area water vapor sensor network made possible by the widespread availability of digital broadcast signals. This paper presents the background and some preliminary results.