Development of radiative transfer model of atmosphere-snow/sea ice system and upgrading of the sea-ice surafce albedo scheme in climate models

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K12142
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: Japan, Meteorological Research Institute
• Principal Investigator: Tanikawa Tomonori 気象庁気象研究所, 気象予報研究部, 主任研究官 (20509989)
• Co-Investigator(Kenkyū-buntansha): 豊田 威信 北海道大学, 低温科学研究所, 助教 (80312411) ; 豊田 隆寛 気象庁気象研究所, 全球大気海洋研究部, 主任研究官 (90450775)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 海氷放射スキーム / 海氷アルベド / 放射伝達 / 海氷 / 積雪 / 気候モデル / 海洋モデル

Outline of Final Research Achievements

In order to improve the accuracy of sea ice prediction by climate models, we upgraded the sea ice radiation scheme (i.e. calculations of sea ice albedo) to represent the shortwave radiation entering the sea ice with high accuracy. The current sea ice radiation scheme is based on empirical parameterizations that were not fully taken into account the snow and sea ice parameters affecting the sea ice albedo. The uncertainties of the sea ice albedo employed in the climate model have been reported. We develop the radiative transfer model of atmosphere-snow-sea ice system based on the radiative transfer theory and then upgrade a new sea ice radiation scheme that incorporated the physical processes to determine the sea ice albedo.

Free Research Field

大気・雪氷放射学

Academic Significance and Societal Importance of the Research Achievements

現在の気候モデルでは近年の北極海の急激な海氷減少傾向を十分に再現できておらず，モデルの改善が必要とされていた．本研究は海氷の放射スキームに焦点を当てて，放射伝達モデルを開発し，物理に基づく海氷放射スキームの高度化を行った．その結果，物理に基づく高度な考察が可能となり，気候変動に対する海氷物理量の関係を詳細に捉えることが可能となった．本研究成果は，季節アンサンブル予報システム等による長期予測にとっても有益であるため，今後，当モデルの適用が期待される．