Comparison of OH rotational temperatures measured by the spectral airglow temperature imager (SATI) and by a tilting-filter photometer

Abstract

Measurements of OH rotational temperatures have been carried out at Shigaraki, Japan (34.8°N, 136.1°E), for 8 nights in September–December 2000, using the Spectral Airglow Temperature Imager (SATI) and a tilting-filter zenith photometer (MC4), simultaneously. Clear positive correlation was obtained between the two temperatures. However, the absolute temperatures obtained by SATI were unusually low (∼130– 180 K ) with differences of ∼60 K from the MC4 temperatures. We discuss possible causes of the temperature differences, particularly for SATI, which newly uses OH(6-2) Q-branch lines (MC4 uses OH(6-2) P-branch lines) and imaging optics for the temperature measurement.