KLAPS를 이용한 한반도 어는비 사례 연구

Abstract

In this study, the occurrence circumstance of 3 cases (12 Jan 2006, 11 Jan 2008, 22 Feb 2009) when the freezing rain was observed at more than two observations in a day with more than three times each observation, was researched. Following the advanced study about the same case, we investigated more delicate differences using the Korea Local Analysis and Prediction System (KLAPS; 5 km reanalysis data) that has the smallest grid scale at current situation. The following characteristics are commonly found in three cases: (1) Just before the occurrence of the freezing rain, the wind direction was consistently continuous and the wind speed was constant or gradually increased for at least 3hours more. (2) Surface air temperature (Relative humidity) was respectively 3.08 °C (28.76%), 0.47 °C (50.07%) and -3.60 °C (71.07%) 3 hours ago to break out the freezing rain and the closer it got to the occurrence time of the freezing rain, the closer a surface air temperature was to 0 °C, and also the more humid the surface air was. (3) The precipitation which was formed in the upper atmosphere met a cold advection at the lower layer than 950 hPa. Due to this, it seemed to change to the super-cooled conditions. In 2006, an increase of the evaporation was analyzed as an additional cause of the occurrence of freezing rain.

Key words: Freezing rain, Cold advection, Melting process, Super-cooled water