Ship-board Sky-radiometry for Investigating Optical Properties of Maritime Aerosols over Oceans Including Polar Regions

Sky-radiometry measures not only spectral solar attenuation but also scattered radiance for investigating column aerosol optical properties based on a passive remote sensing technique. We have used ship-based sky-radiometers which are installed on Japan’s Antarctic Research Vessel Shirase for on-board measurements during voyage between Japan and Antarctica since early 2000’s. However, we have learned that the performance of existing instruments which are commercially available for ship-based measurements is still insufficient for accurately tracking the sun against large rolling/pitching of the ship, and available data for analyses are very limited. Therefore, we have developed a new instrument, named Ship-borne Aureolemeter SAURE, which is capable of continuous measurements of spectral sun/sky radiance aboard rocking vessels. SAURE is successfully working for investigating maritime aerosols on board R/V Shirase since the 2015/2016 Antarctic cruise. Also, we have planned to deploy SAUREs to foreign vessels. The first opportunity of the deployment following R/V Shirase was provided to Korean Ice-breaking R/V Araon. SAURE was installed on R/V Araon for the 2017/18 Antarctic cruise between Korea and the Antarctic. In this paper, we will show results from on-board measurements using Prede POM01 Mk III and SAURE during the Antarctic cruises by R/V Shirase for the Japanese Antarctic Research Expeditions and the first result from the SAURE measurement on board R/V Araon for the Korean Antarctic Research Program.