气象科技进展
氣象科技進展
기상과기진전
Advances in Meteorological Science and Technology
2015年
5期
24-32
,共9页
钱恺%刘锦丽%毕永恒%韩永%吕达仁
錢愷%劉錦麗%畢永恆%韓永%呂達仁
전개%류금려%필영항%한영%려체인
暴雨%中尺度对流系统%测雨雷达%测云雷达%风廓线雷达
暴雨%中呎度對流繫統%測雨雷達%測雲雷達%風廓線雷達
폭우%중척도대류계통%측우뢰체%측운뢰체%풍곽선뢰체
rainstorm%meso-scale convective system%weather radar%cloud radar%wind proifle radar
利用S波段测雨雷达、毫米波测云雷达、风廓线雷达等观测资料对2011年6月23日和2012年7月21日(以下简称7·21暴雨)发生在北京地区的两次中尺度对流系统(MCS)引起的大暴雨观测资料进行分析,结果表明:导致两次暴雨的回波均具有线状对流特征,其组织形态为平行层状(PS)降水中尺度对流系统;两次暴雨中PS型MCS与长江中下游地区此类MCS移动方向偏东或东北略有不同,而是向偏东或东南方移动,但7·21暴雨过程中最后阶段影响北京形成的PS型MCS却是向东北移动的。毫米波测云雷达可以观测到测站上空及周边云的形态特征及发展情况,回波强度及速度可以展现出云的演变、内部结构特征以及降水状态。而风廓线资料表明两次暴雨在风场变化中均存在着相似的特征,两次暴雨前期低层均存在东风层,这与北京特殊地形的共同作用可能是导致夏季强降水的因素之一;同时,暴雨发生之前存在对流层低层风速明显增大的过程。低层扰动的加强、风向之间的切变以及超低空急流均有可能是导致强降水的原因。
利用S波段測雨雷達、毫米波測雲雷達、風廓線雷達等觀測資料對2011年6月23日和2012年7月21日(以下簡稱7·21暴雨)髮生在北京地區的兩次中呎度對流繫統(MCS)引起的大暴雨觀測資料進行分析,結果錶明:導緻兩次暴雨的迴波均具有線狀對流特徵,其組織形態為平行層狀(PS)降水中呎度對流繫統;兩次暴雨中PS型MCS與長江中下遊地區此類MCS移動方嚮偏東或東北略有不同,而是嚮偏東或東南方移動,但7·21暴雨過程中最後階段影響北京形成的PS型MCS卻是嚮東北移動的。毫米波測雲雷達可以觀測到測站上空及週邊雲的形態特徵及髮展情況,迴波彊度及速度可以展現齣雲的縯變、內部結構特徵以及降水狀態。而風廓線資料錶明兩次暴雨在風場變化中均存在著相似的特徵,兩次暴雨前期低層均存在東風層,這與北京特殊地形的共同作用可能是導緻夏季彊降水的因素之一;同時,暴雨髮生之前存在對流層低層風速明顯增大的過程。低層擾動的加彊、風嚮之間的切變以及超低空急流均有可能是導緻彊降水的原因。
이용S파단측우뢰체、호미파측운뢰체、풍곽선뢰체등관측자료대2011년6월23일화2012년7월21일(이하간칭7·21폭우)발생재북경지구적량차중척도대류계통(MCS)인기적대폭우관측자료진행분석,결과표명:도치량차폭우적회파균구유선상대류특정,기조직형태위평행층상(PS)강수중척도대류계통;량차폭우중PS형MCS여장강중하유지구차류MCS이동방향편동혹동북략유불동,이시향편동혹동남방이동,단7·21폭우과정중최후계단영향북경형성적PS형MCS각시향동북이동적。호미파측운뢰체가이관측도측참상공급주변운적형태특정급발전정황,회파강도급속도가이전현출운적연변、내부결구특정이급강수상태。이풍곽선자료표명량차폭우재풍장변화중균존재착상사적특정,량차폭우전기저층균존재동풍층,저여북경특수지형적공동작용가능시도치하계강강수적인소지일;동시,폭우발생지전존재대류층저층풍속명현증대적과정。저층우동적가강、풍향지간적절변이급초저공급류균유가능시도치강강수적원인。
By using S-band weather radar, 8.6 mm wave-length cloud radar and wind proifle radar data, the two heavy rainfalls in June 23, 2011 (hereinafter referred to as the 6·23 rainstorm) and July 21, 2012 (hereinafter referred to as the 7·21 rainstorm), which occurred in Beijing area, are caused by a meso-scale convective system (MCS). Observation results show that the characteristics of linear convection were found in two rainstorms, and its organization mode was classiifed as parallel stratiform MCS (PS). Such MCSs in the middle and lower reaches of the Yangtze River move to the east or northeast, but these two MCSs move to the east or southeast. However, the PS which affect Beijing during the ifnal stages is moving to the northeast. Millimeter wave cloud radar could observe the morphological characteristics and development of the cloud over the station. The intensity and velocity of the echo show the evolution, internal structure of the cloud and precipitation state. The wind proifler data indicate that similar changes of the wind ifeld existed in two rainstorms. The interaction of the east wind in the boundary layer during its early stages and the special terrain might be one of the factors leading to the heavy rain in that summer, Beijing. Meanwhile, the velocity in low-troposphere increases signiifcantly before rainstorm. The strengthening of low-level disturbances, wind direction shear and the ultra low-level jet are likely to be the causes of heavy precipitation.