[A-AS01] 大気の鉛直運動を基軸とした地球環境学の新展開

[AAS01-P07] Effect of particle shape of hydrometeors on vertical motion of the atmosphere

★Invited Papers

*幾田 泰酵¹、佐藤 正樹²、Woosub Roh²、松岸 修平²、久芳 奈遠美²、清木 達也³、梅原 章仁¹、永戸 久喜¹ (1.気象庁気象研究所、2.東京大学大気海洋研究所、3.国立研究開発法人　海洋研究開発機構)

Cloud precipitation processes play a major role in the vertical transport of heat and water vapor in the troposphere. In this study, we use a numerical weather prediction (NWP) model to clarify the interaction between cloud precipitation processes and the vertical motion of the atmosphere. The accuracy of NWP models in predicting cloud precipitation processes is highly dependent on the accuracy of cloud microphysical schemes. The cloud microphysics scheme is built on some assumptions. Particle shapes are often assumed to be spherical for computational simplicity. Recently, however, some schemes have changed the particle shape from spherical to non-spherical. In addition, verification using dual-polarimetric radar has also been performed for predicted hydrometeors. We have developed a cloud microphysics scheme that incorporates nonspherical particles and implemented it in the Japan Meteorological Agency (JMA) non-hydrostatic model ASUCA, which is used in the regional models Meso-scale Model and Local Forecast Model at JMA. The shape of raindrops was assumed to be an oblate that depends on particle size. Snow was assumed to have three different shapes. The forecast using the scheme was validated by radar observations as reference values and showed good performance. The increase in the number of snow particle types resulted in a change in the amount of snow that stayed in the air due to a change in the fall velocity. Since diffusion growth is dependent on particle shape, changes in particle shape affect the amount of heating due to phase change, resulting in changes in latent heat profiles. The effect of these profile changes on vertical motion is discussed.