Starting long-term stratospheric observations with RAMAS at Summit, Greenland

The new microwave Radiometer for Atmospheric Measurements at Summit (RAMAS) has started operation at Summit station, Greenland (72[degrees]N, 38[degrees]W, 3200 m), and is now being prepared for continuous measurements. RAMAS operates in the frequency band from 265-280 GHz with an instantaneous bandwidth of currently 1 GHz. It observes the emission of thermally induced rotational transitions of a variety of stratospheric trace gases, including [O.sub.3], CIO, [N.sub.2]0, HN[O.sub.3], and HCN. Tropospheric water vapor content, a major constraint on ground-based microwave radiometry, is exceptionally low at Summit station. Initial measurements and retrieved profiles are presented, demonstrating the excellent measurement conditions. Index Terms--Ground based, microwave radiometry, new instrument, ozone, stratosphere.