CAJ | 학술논문

应用常规探测资料和NCEP再分析资料，对2011年2月下旬典型华北回流形势下天津地区一次大到暴雪天气进行诊断分析。结果表明：回流降雪过程中，华北上空西风环流以纬向型为主，冷空气主体偏北，影响系统为华北回流冷高压和低压倒槽。同时，回流降雪中有浅薄的冷空气垫，其上有暖湿气流爬升，爬升高度为650hPa。回流降雪期间，有来自西南和东北两个方向的水汽在天津地区交汇，西南方向的水汽较为暖湿，东北方向的水汽相对干冷；低空和超低空为一致的东北气流，900hPa存在超低空急流，700hPa以上为西南暖湿气流。降雪过程中，对流层低层至高层均为一致的强上升运动，高度达200hPa，对应于低空和超低空有强辐合。降雪开始前，天津及其周边地区有较强的对流不稳定能量和对称不稳定性，有利于对流的发展。
응용상규탐측자료화NCEP재분석자료，대2011년2월하순전형화북회류형세하천진지구일차대도폭설천기진행진단분석。결과표명：회류강설과정중，화북상공서풍배류이위향형위주，랭공기주체편북，영향계통위화북회류랭고압화저압도조。동시，회류강설중유천박적랭공기점，기상유난습기류파승，파승고도위650hPa。회류강설기간，유래자서남화동북량개방향적수기재천진지구교회，서남방향적수기교위난습，동북방향적수기상대간랭；저공화초저공위일치적동북기류，900hPa존재초저공급류，700hPa이상위서남난습기류。강설과정중，대류층저층지고층균위일치적강상승운동，고도체200hPa，대응우저공화초저공유강복합。강설개시전，천진급기주변지구유교강적대류불은정능량화대칭불은정성，유리우대류적발전。
Based on the conventionally meteorological observation data and the NCEP reanalysis data, a heavy snowstorm process in the last ten-day period of February of 2011 in Tianjin area was diagnosed. This process was under the situation of typical return-flow weather in the north China. The results show that the westerly circulation over the north China is mainly the zonal type during the return-flow snowfall process. Cold air mainly leans to northward, and the main influencing systems are the return-flow cold high in the north China and low pressure in- verted trough. At the same time, there exists a thin cold air cushion in return-flow snowfall accompanied by the climbing of warm-wet air that can reach about 650 hPa. During the process of the return-flow snowfall, the south- westerly warm-wet air and northeasterly cold-dry air converges in Tianjin area, and it is the northeast air flow at low or ultra low levels. Ultra low level jet stream and southwest warm-wet air flow appear near 900 hPa and above 700 hPa,respectively. There is the uniform strong ascending motion from the low to high troposphere during the snowfall and the ascending height can reach 200 hPa, which corresponds to the strong low-level and ultra-low-level convergence. The convective instability energy and symmetry instability are strong before snowfall in Tianjin and its surrounding area, which is favorable to the development of convection.