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エアロゾルによる雲と降雨への影響の検出
河本, 和明
Permalink : http://hdl.handle.net/2115/55032
Abstract
現在の気候システムにおいて最も不確かな過程の一つとして認識されているエアロゾルによる雲と降雨への影響について, 観測的研究, 特に人工衛星からの観測事例を中心に紹介する. 雲の光学的厚さと雲粒サイズへの影響は概ねTwomey効果を支持する結果となっており, また雲量への影響は, エアロゾルの吸収性の有無とその雲層との相対的な位置で変わることが示された. 降雨への影響については, エアロゾルの増加につれて増加する例と減少する例が報告されており, 現時点では明確な結論は得られていない. これらの現象は主に相関関係によって調べられているが, エアロゾル以外の他の原因についても検討されている.
On the effect of aerosols on clouds and precipitation, which is recognized as one of the most uncertain processes in the current climate system, observational examples, in particular, from satellites, are introduced. The effect on the cloud optical depth and cloud droplet size is generally consistent with the Twomey effect. The effect on the cloud fraction is shown to be variable depending on the aerosol absorptivity and the relative height to the cloud layer. As for the effect on the precipitation, both increase and decrease cases are reported and no clear conclusion has been given at this moment. Although these phenomena are investigated mainly through the correlation, other reasons than aerosols are also examined.
On the effect of aerosols on clouds and precipitation, which is recognized as one of the most uncertain processes in the current climate system, observational examples, in particular, from satellites, are introduced. The effect on the cloud optical depth and cloud droplet size is generally consistent with the Twomey effect. The effect on the cloud fraction is shown to be variable depending on the aerosol absorptivity and the relative height to the cloud layer. As for the effect on the precipitation, both increase and decrease cases are reported and no clear conclusion has been given at this moment. Although these phenomena are investigated mainly through the correlation, other reasons than aerosols are also examined.
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