윈드프로파일러를 이용한 서해안의 집중호우 특성 연구 (군산 사례를 중심으로)

Abstract

With the recent climate change, the frequency and intensity of heavy rainfall has been increasing as times passes. In this regard, continuous research is needed. In this study, the case of more than 70 mm in daily rainfall that occurs in Gunsan where a wind profiler was installed from June to September when high frequency of heavy rainfall appears from the past five years(2009-2013) was selected for analysis. Vertical characteristics were analyzed, using horizontal wind, vertical wind, vertical wind shear and hodograph which were calculated from wind profiler, along with an analysis for the prediction of heavy rainfall using CAPE, SRH and SWEAT among stability indices. The results of horizontal wind analysis showed that a low-level jet of 25 kts exists at an altitude of less than 850 hPa in nine out of total of 10 cases, thereby we can infer the fact that the rainfall varies depending on changes in the height and range of the low-level jet. The vertical wind analysis identified the start of rainfall and convention, and rainfall in concentrated from, and confirmed that in case it develops into a convective from, the vertical wind rises to near the area of 3 km before the start of rainfall. The analysis of the vertical wind shear found that the vertical wind shear becomes stronger at an altitude of 1 km of less before the start of rainfall, and the strong mid-layer vertical wind shear is distributed at the point of time when the rainfall is concentrated. The characteristics of heavy rainfall according to wind direction shear and wind speed shear were also identified by classifying the type of the hodograph. In the analysis of the stability index, it was difficult to predict the concentrated time of heavy rainfall only with value greater than or equal to the threshold in the case of CAPE which represent the thermal buoyancy energy. However, it was possible th have an access to the concentrated time when used in conjunction with SRH that displays a dynamical vorticity. As for SWEAT, since the contents regarding upper-layer wind and thermal energy are included in the calculation method, it was found to show a significant relevance in the prediction of heavy rainfall. A synoptic from and a locally vertical from were analysis by selecting the case (2012. 8. 12-13) which well represent the wind speed shear and wind direction shear of the hodograph, changes in vertical wind shear of lower and upper level, and vertical wind and low-level jet identified in all cases. A comprehensive analysis was preformed by comparing the reanalyzed vertical cross section using KLAPS data, with the data from wind profiler, and yielding the stability index. According to the results, change of low-level jet at the point of time when the rainfall started and vertical change of concentrated rainfall time were verified, and significant accessibility toward the concentrated time was confirmed in case the stability index was substituted.