[A-AS01] Evolution of Global Environmental Research based on Atmospheric Vertical Motions

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

★Invited Papers

*Yasutaka Ikuta¹, Masaki Satoh², Woosub Roh², Shuhei Matsugishi², Naomi Kuba², Tatsuya Seiki³, Akihito Umehara¹, Hisaki Eito¹ (1.Japan Meteorological Agency/Meteorological Research Institute, 2.Atmosphere and Ocean Research Institute, The University of Tokyo, 3.Japan Agency for Marine-Earth Science and Technology)

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.