[A-AS07] The Beginning of Cloud Aerosol and Radiation Sciences with EarthCARE

[AAS07-05] Cloud microphysical balances in cirrus clouds identified by using doppler velocity and radar reflectivity factor observations

*Tatsuya Seiki¹, Akira T Noda¹, Yuichiro Hagihara, Hiroaki Horie (1.Japan Agency for Marine-Earth Science and Technology)

Keywords:cloud microphysics, doppler velocity, radar reflectivity factor, ground observations

Cloud microphysical parameters have been estimated based on observations conducted within the temperature range of 0 to -30 degree celsius, and in lower-temperature regions, extrapolated values (or globally fixed constants) have been used. It is fundamentally difficult to directly observe the growth of ice cloud particles under extremely low-temperature conditions and, consequently, to constrain the uncertainties in the parameters included in the theoretical formulations of cloud microphysics. Therefore, these estimates in cloud microphysics schemes generally lack physical reliability in cirrus simulations. The cloud microphysical processes occurring within cirrus clouds, which are widely distributed in the upper troposphere, are dominated by three mechanisms: collision, sublimation, and gravitational settling. The number of uncertain parameters in the theoretical modeling of these processes is relatively small. Therefore, the aim of this study is to investigate the balance of particle growth across a two-dimensional parameter space and constrain the uncertain parameters by utilizing simultaneous observations of radar echoes and Doppler velocities.
To validate the theoretical framework of cloud microphysics, ground-based observations using HG-SPIDER is employed. Furthermore, the separation of sublimation and collision effects within the two-dimensional parameter space is achieved using climate models. For the climate model analysis, a budget analysis of radar reflectivity is conducted.