KLAPS 재분석 자료를 활용한 2009년 7월 9일 호우사례에 대한 기상특성

Abstract

In this paper, meteorological characteristics associated with heavy rainfall of July 9, 2009 and its developing mechanism were examined by analyzing synoptic weather pattern and dynamical index obtained from KLAPS (Korea Local Analysis and Prediction System) reanalysis data. The KLAPS developed by Korea Meteorological Administration has some advantages of producing high-resolution reanalysis data with temporal resolution of 1 hour and spatial resolution of 5 km and assimilating intensive observing data from wind profiler and marine observation vessel. The dynamical indexes used in this study are instantaneous contraction rate (ICON), horizontal velocity gradient tensor magnitude (MAG), helicity, and superhelicity.

The synoptic weather analyses showed that heavy rainfall is caused by low system along the Changma front extending from Shangdong province, China to Japan peninsula through the central part of the Korean peninsula. This case was largely associated with higher (333K more) equivalent potential temperature, strong LLJ, positive velocity potential more than at 850hPa. Daily rainfall with 229.5 mm in Hongcheon and 190mm in Seoul on July 9, 2009 intensively occurred over the central part of the Korean peninsula. The main rainfall belt moved southeastward and then reached northern part of Gyeongbuk province at 1800LST 9 July, 2009, as indicated in radar reflectivity and satellite IR image.

The dynamical index analysis revealed that ICON and MAG well separate regions with and without heavy rainfall and the areas with positive and negative helicity alternatively well reflect strong rainfall belt of Seoul, Gyeonggi and Gangwon provinces. The maturity of rainfall cell can be confirmed by superhelicity, indicating the fact that large negative superhelicity shows the developing rainfall cell over the regions.

Finally, results from this case study showed that the high possibility of occurring heavy rainfall is well characterized by dynamical index from KLAPS reanalysis data. In particular, rainfall occur over the area where helicity and helicity density is around zero.