Doppler wind and temperature sounder: new approach using gas filter radiometry

Abstract

We present a new approach for measuring high-altitude winds and temperatures. We describe how gas filter correlation radiometry can be employed from low Earth orbit to simultaneously measure the Doppler shift and linewidth of emission spectra to infer both wind and kinetic temperature. Measurements are performed with a simple radiometer that images the limb emission of nitric oxide near 5.3 μm (to sense altitudes of >90 km and <50 km) and carbon dioxide near 4.4 μm (to sense altitudes of <110 km). Observations are made through a single low-pressure gas cell containing a mixture of these target gases. Profiles of temperature and wind can be measured day and night continuously from 25 to over 250 km with <2% uncertainty at intervals of 10 km along-track, far exceeding current capabilities. This approach, using a small, simple, moderately cooled IR camera, could provide unprecedented observations of atmospheric dynamics from the lower stratosphere into the middle thermosphere.