Downsizing of a ship-borne MAX-DOAS instrument

Abstract

Trace gases and aerosol measurements over ocean by ship-borne Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) on a Japanese research vessel, Mirai, have been conducted since 2010．At the beginning, we conducted the measurements by using active gimbal to ensure the light-receiving device was kept horizontal, and a two-axis telescope unit was mounted on the gimbal. To downsize the observation system, we have been developing a one-axis-type telescope unit without gimbal, in which the target elevation angle is attained by actively adjusting the angle of the prism, accounting for the ship roll angle. During the cruises from November 2014 to February 2015 (MR14-06), the target elevation angle was attained to within ±0.5° for > 95％ of the time.