레이더를 이용한 남서해안의 호우 사례 특성 분석 : 태풍 "민들레" 에 의한 집중호우를 중심으로

Abstract

Weather radar is a useful instrument for retrieving the variation and movement of wind filed in the mesoscale cloud system. Research was conducted to analyze the precipitation structure and characteristics of mesoscale system causing heavy rainfall using the various radar data analysis including wind field analysis and micro rain radar data by dual Doppler weather radar, and single radar reflectance analysis. For seven days from July 3 2004 to 9, southern area had heavy rainfall by typhoon Mindule and increased the activity of stationary front by influence of typhoon, and heavy rain moved to middle areas. From the analysis of rainfall characteristics by micro rain radar, precipitation intensity was shown at 11.5 mm per hour on 0700 LST July 4 at Haenam, and it showed that precipitation particles with the size of 4 mm were homogeneously distributed as a functions of size and height. Number concentration has increased to 101~106 logarithmically when the size was small. These results provide guidelines for quantitative analysis of mesoscale precipitation characteristics causing heavy rain. The results also provide more systematic understanding of collision/coalescence process related to increased process of precipitation. On the other hand, precipitation intensity showed high at surface and decreased with increase of height; and it showed close relationship between precipitation intensity and increase of size by vertical collision/coalescence process. Moreover, the accuracy of precipitation intensity showed good relationship with correlation of 0.9 by compared to optical rain-gauge at surface and decreased with increase of height; and it explains the radar attenuation effect by precipitation particle increased with height. Even though rain area forecasting by synoptic system is possible in the numerical forecasting area, in this case of heavy rainfall developed in a short time by mesoscale system, there are limitations of numerical models for accurately forecasting heavy rainfall area and precipitation. Therefore it is necessary to analyze synoptic measurements in order to prevent the natural disaster by severe weather. The necessity of using a highresolution non-synoptic measurement data including satellite and radar for predicting locally developed heavy rain are recognized. On the other hand, we investigated the horizontal and vertical structure of system causing heavy rainfall by non-synoptic measurement data including satellite and radar, and especially from three dimensional wind field obtained from the dural Doppler radar analysis. There were strong vertical shear and surface divergence in the strong reflectance area, and there were strong convergence area in the surface with upper wind. Also there are suitable situations for developing and sustaining mechanisms due to the developed divergence of downwind which caused by the precipitation near the 'strong' system and strong converging area at surface in front of the system . Although it is not possible to accurately determine the mesoscale system accompanied by heavy rainfall activated on quantitative-basis by stationary front as well as both 'direct' and 'indirect' typhoon, it is helpful to understand the developing and sustaining mechanisms by measurement data analysis. It is expected to be used for forecasting and analysis of precipitation structure and characteristics of mesoscale system causing heavy rainfall using the various high-resolution non-synoptic data including reflectance and wind field analysis of weather radar, micro rain radar, and optical rain-gauge.