CAJ | 학술논문

文中利用中尺度数值模式MM5模拟了台风泰利的登陆过程,模拟的台风路径、天气形势和降水都与观测基本一致,能够很好地反映出真实的天气过程.再利用数值模拟结果,研究了第二类热成风螺旋度(H_2)对登陆台风泰利降水的诊断能力,结果表明它对深入内陆的台风强降水具有较好的诊断能力,而对刚登陆前后的台风降水诊断能力不如经典螺旋度.特别地,H_2在提前1 h时与泰利降水达到最高相关系数,且在提前1-5 h时,它与降水的相关性比经典螺旋度的高,表现出十分显著的预示降水增幅的能力.进一步分析表明,在刚登陆前后,泰利台风中心850-200 hPa的风场垂直切变较小(约5 m/s),其最强降水出现在路径右侧300 km半径范围以内,与低空的正温度平流、低空辐合、高空辐散等无明显的关系,而低空相对涡度能够很好地反映降水的变化,这是经典螺旋度与降水在这一阶段相关性优于H_2的主要原因.而在深入内陆后,台风泰利本体环流减弱,受北部西风槽的影响逐渐增强,环境风场垂直切变迅速增大,发生强降水的庐山和大别山区处于顺垂直风切变方向左侧.在东北向的垂直风切变情况下,庐山和大别山强降水区上空有向东的高空急流出流,强高空辐散诱发垂直次级环流,从而激发对流,形成强上升运动区,因此H_2的诊断优势在这一阶段表现得最清楚.
문중이용중척도수치모식MM5모의료태풍태리적등륙과정,모의적태풍로경、천기형세화강수도여관측기본일치,능구흔호지반영출진실적천기과정.재이용수치모의결과,연구료제이류열성풍라선도(H_2)대등륙태풍태리강수적진단능력,결과표명타대심입내륙적태풍강강수구유교호적진단능력,이대강등륙전후적태풍강수진단능력불여경전라선도.특별지,H_2재제전1 h시여태리강수체도최고상관계수,차재제전1-5 h시,타여강수적상관성비경전라선도적고,표현출십분현저적예시강수증폭적능력.진일보분석표명,재강등륙전후,태리태풍중심850-200 hPa적풍장수직절변교소(약5 m/s),기최강강수출현재로경우측300 km반경범위이내,여저공적정온도평류、저공복합、고공복산등무명현적관계,이저공상대와도능구흔호지반영강수적변화,저시경전라선도여강수재저일계단상관성우우H_2적주요원인.이재심입내륙후,태풍태리본체배류감약,수북부서풍조적영향축점증강,배경풍장수직절변신속증대,발생강강수적려산화대별산구처우순수직풍절변방향좌측.재동북향적수직풍절변정황하,려산화대별산강강수구상공유향동적고공급류출류,강고공복산유발수직차급배류,종이격발대류,형성강상승운동구,인차H_2적진단우세재저일계단표현득최청초.
This study utilizes the MM5 mesoscale model to simulate the landfalling process of the Typhoon Talim. The simulated ty-phoon track, weather patterns, and rainfall process could well represent the observation. Using the numerical simulation outputs, the relation of the second type thermal helicity (H_2) to rainfall caused by the landfalling typhoon Talim is analyzed. The results show that H_2 can reflect the heavy inland rainfall well while the relation was not as good as that of helicity to rainfall during the beginning landfalling stage. In particular, H_2 had the highest correlation coefficient with rainfall of Talim 1 h in advance. For 1 - 5 h prediction times, it had a higher correlation with rainfall than helicity, and thus it showed a better potential in forecasting rainfall intensifica-tion. Further analyses have found that when Talim was in the beginning stage of landfall, the 850 - 200 hPa vertical wind shear around the Talim center was quite small (about 5 m/s). The highest rainfall was to the right of the Talim track and in the 300 km radius area around the Talim center, and it had no obvious relation with low-level temperature adveetion, low-level air convergence, or upper-level divergence. But the low-level relative vorticity could reflect the rainfall change quite well, which was the main reason why helicity had a better performance than H_2 in this period. But after Talim moved inland further, it weakened gradually and was affected increasingly by the northern trough, and the vertical wind shear was increasing as well. The left side of the down vertical wind shear direction lies the Lushan and Dabieshan mountain area, which could have contributed to intriguing a secondary vertical cir-culation, and thus heavy rainfall was produced over there. Hence, H_2 showed a better capacity to reflect the rainfall change during this stage.