[U-02] 地球規模環境変化の予測と検出

[U02-P02] MIROC6における降水過程精緻化による雲の温暖化応答への影響

*廣田 渚郎¹、道端 拓朗²、塩竈 秀夫¹、小倉 知夫¹、鈴木 健太郎³ (1.国立環境研究所、2.岡山大学、3.東京大学)

キーワード：地球温暖化、降水過程、MIROC6、雲フィードバック

Uncertainties in global mean temperature projections are primarily associated with the spread in cloud feedback across models, which accelerate or decelerate global warming through cloud sunshade and/or greenhouse effects. A possible reason for the spread in cloud response is the overly simplified treatment of precipitation in models, where rain and snow particles immediately fall from the atmosphere down to the surface within a single model time interval of about 10 min. Here, we introduced a more sophisticated precipitation scheme that explicitly calculates the physical processes of falling rain and snow particles, thus preserving their “memory” in the atmosphere with their sunshade and greenhouse effects incorporated. As a result, the representation of clouds is significantly improved in this model, and greenhouse effects by clouds in warming climates are significantly enhanced. This study lends credence to higher cloud feedback and climate sensitivity if models incorporate the missing feedback processes in line with observational constraints.