CAJ | 학술논문

采用中国西北地区1960?2009年6?8月常规气象观测站24 h (20：00?20：00)降水资料和NCEP/NCAR (2.5?×2.5?)1960?2009年再分析逐日4次的850,700,600,500 hPa位势高度、比湿q和U , V 风场资料.在分析西北地区降水概况的基础上,通过NOAA HYSPLIT_4水汽轨迹模型和常规诊断分析方法,对2005年7月1?2日降水过程进行了分析,结果表明：中国西北地区暴雨的主要特点是降水频率低,降水频数有明显的年际变化特征；降水时间相对集中,主要集中在7月和8月；降水持续时间短,且降水时间持续2天(包括2天)以上的过程性降水次数有明显的年代分布特征.西北地区降水的环流形势主要以西低东高型和偏南气流型为主.利用HYSPLIT后向轨迹模型,对2005年7月1?2日降水过程向前360 h追踪水汽输送轨迹,发现水汽主要来自偏南气流；但是,不同等压面上水汽轨迹并不总是一致的,降水量越大,不同等压面上的水汽输送轨迹越趋于一致.通过物理量的诊断分析,表示水汽来源的水汽通量分布与后向轨迹模型给出的水汽来源一致.因此在本个例中,后向轨迹模型可以作为判断降水过程中水汽来源的方法之一,并且此次降水过程伴随强烈的上升运动和对流层中下层的强辐合及高层的辐散气流.
채용중국서북지구1960?2009년6?8월상규기상관측참24 h (20：00?20：00)강수자료화NCEP/NCAR (2.5?×2.5?)1960?2009년재분석축일4차적850,700,600,500 hPa위세고도、비습q화U , V 풍장자료.재분석서북지구강수개황적기출상,통과NOAA HYSPLIT_4수기궤적모형화상규진단분석방법,대2005년7월1?2일강수과정진행료분석,결과표명：중국서북지구폭우적주요특점시강수빈솔저,강수빈수유명현적년제변화특정；강수시간상대집중,주요집중재7월화8월；강수지속시간단,차강수시간지속2천(포괄2천)이상적과정성강수차수유명현적년대분포특정.서북지구강수적배류형세주요이서저동고형화편남기류형위주.이용HYSPLIT후향궤적모형,대2005년7월1?2일강수과정향전360 h추종수기수송궤적,발현수기주요래자편남기류；단시,불동등압면상수기궤적병불총시일치적,강수량월대,불동등압면상적수기수송궤적월추우일치.통과물리량적진단분석,표시수기래원적수기통량분포여후향궤적모형급출적수기래원일치.인차재본개례중,후향궤적모형가이작위판단강수과정중수기래원적방법지일,병차차차강수과정반수강렬적상승운동화대류층중하층적강복합급고층적복산기류.
The landform of Northwest China is diversified, the underlying surface is complex and heavy rain precipitation accounts for a high proportion. Thus, heavy rain plays an important role in a study of the precipitation and drought in Northwest China. The observational precipitation data from June to August in 1960?2009, and the NCEP/NCAR (2.5?×2.5?) daily reanalysis data from 1960?2009 were used to analyze the heavy rain in Northwest China. On that basis, the precipitation process (2005.7.1?2) were analyzed using the HYSPLIT-4 model and diagnostic analysis methods. The results showed that heavy rains in this part of China were of less precipitation frequency. Precipitation frequency had obvious characteristics of decadal variety, with precipitation centred entirely on July and August. The duration of precipitation process was generally short, and the duration heavy rains reaching more than 2 days (including 2 days) showed obvious characteristics of decadal distribution. The circulation situation of precipitation in Northwest China was dominated by ow-lying west high east and southerly air. The water vapor was mainly from the south warm air, and the vapor tracks in different isobaric surfaces did not always coincide. The vapor tracks in different isobaric surfaces reached converged similarly when the precipitation was high. The source of vapor given by the distribution of vapor flux was in conformity with the pattern of backtracking. Therefore, the HYSPLIT-4 Model could be used as a new method to measure the source of vapor during precipitation process. The heavy rainfall process comes with strong upward motion, strong convergence of lower troposphere and divergent airflow of higher troposphere.