Radar-acoustic measurement of temperature using a volume-imaging UHF wind profiler

Abstract

The University of Massachusetts Microwave Remote Sensing Laboratory (MIRSL) has augmented the Turbulent Eddy Profiler (TEP) with an acoustic source to implement a Radio Acoustic Sounding System (RASS). TEP is a volume-imaging 915 MHz radar wind profiler. It can be thought of as a densely packed array of 915 MHz wind profilers sharing a common transmitter. Using digital beamforming techniques, TEP simultaneously generates over 40 contiguous beams within a 25 degree field of view. As a result, TEP provides a four-dimensional view (3D volume and time) of atmospheric turbulence structure within a volume of the boundary layer. The addition of RASS capabilities to TEP allows it to measure virtual temperature. In principle, the TEP-RASS system is capable of measuring three-dimensional temperature fields. However, the horizontal resolution is limited in practice by the size of the reflected and acoustically-focused electromagnetic radiation incident on the receiving array. In this paper we present the TEP-RASS system implementation and an assessment of the feasibility of measuring horizontal temperature variations via RASS technique.