[세미나] 이규원 교수

A MAGIC LAYER AROUND -15°C: DYNAMICAL AND MICROPHYSICAL PROCESSES

이규원 교수

2022년 11월 1일 (화) 16:00

과학관 B102호

Abstract

Microphysical and dynamical processes are intertwined, in particular, in diabatic feedback into atmospheric stability and supersaturation by heat driven upward motion. The layer around -15°C to -17°C has a maximum excess vapor density over ice in the atmosphere saturated with respect to plane water. Thus, a lateral growth such as dendritic growth is dominant. In the literature, this layer showed distinctive signature of ZDR maximum and KDP maximum below. Many researchers explained this signature as dendritic growth but a rapid growth of smaller pristine or planar crystal was needed to explain rapid increase of KDP maximum below. The existence of smaller ice particle was proved by bi-modal Doppler power spectra from vertical pointing cloud radar measurement. To understand microphysical and dynamical processes in this layer, an intensive field experiment was executed in the Pyeongchang-Kangneung area during the winter Olympics games. This research shows similar bi-modal spectra, and ZDR and KDP feature around this layer. In addition, we found mesoscale ascent below the layer from vertical pointing radar data in climatological sense. Thus, we speculate that a new ice nucleation in increased supersaturation condition is most feasible explanation for the secondary ice production (SIP). This supersaturation can be explained by the combined effect of mesoscale ascent below and diabatic heating due to excess vaper density. We will present the field experiment including an overview of instrumentations and their networks and findings on the processes in the layer.

KEYWORD

field experiment, Microphysical and dynamical processes, excess vaper density, -15°C, dendritic growth, bi-modal spectrum, mesoscale ascent, secondary ice production (SIP)