中国地区高空气象探测气球空间漂移分析

The analysis of upper-air meteorological balloon floating in China.

利用中国120个探空站2004年08时所有探空气球漂移信息,结合NCEP再分析场,分析规定等压面上的时空漂移规律,重点选择100、500与925 hPa等压面,采用1、4、7、10月分别代表冬季、春季、夏季、秋季4个季节。初步分析表明;气球的漂移方向主要是受大气环流影响,不同季节中国受不同的系统影响,导致漂移的方向差异明显,夏季以西南漂移为主,冬季、春季与秋季以西北漂移为主,但是在100 hPa以上4个季节均以西南漂移为主,以冬季的漂移距离最大,漂移距离超过120km,夏季最小,约为40 km,春、秋季次之,接近70 km。漂移距离的差异东部比西部显著;沿经圈漂移以向南为主,冬、春与秋季沿经圈漂移以向南为主,春季漂移最大,超过5 km;冬、秋季节漂移距离分别超过3与2 km,夏季沿经圈漂移受大尺度环流影响,200 hPa以下向北漂移,最远漂移超过1 km,200 hPa以上转向南漂移,最远漂移达3 km;沿纬圈以向东为主,以冬季最大,达77 km,夏季最小,接近13 km,春、秋季次之,分别达49和46 km;沿纬圈漂移量要大于沿经圈漂移量,沿纬圈漂移全年平均接近60 km,沿经圈漂移量全年平均接近3.5 km,有量级上的差别;从低层到高层漂移量呈增大趋势,漂移大的范围随高度往西扩张;探空漂移的整体分布范围较大,并且比较均匀。同时还选取了个例分析低空急流条件下探空漂移,结果显示对于中小尺度天气系统不可忽略。

All balloon floating information from 120 Chinese upper-air meteorological sounding stations are utilized to analyze the temporal and spatial floating characteristics on standard constant pressure surfaces integrated with the NCEP reanalysis data.The data of January,April,July and October of 2004 with the focus on 100,500 and 925 hPa are chosen to represent winter,spring,summer and autumn,respectively.The results show that floating direction is mainly affected by atmospheric circulations which comprise different features in different seasons in China,causing obvious floating difference：（e.g.） southwest floating dominates in summer while northwest floating in the other seasons with southwest floating dominated above 100 hPa in all of the four seasons;the maximal floating distance of over 120 km occurred in winter and the minimal one of about 40 km occurred in summer with the intermediate floating distance of near 70 km in spring and autumn.Difference in the floating distance is more significant in the eastern part of China than that in the western part.The longitudinal floating is mainly southward in winter,spring and autumn with the maximal floating distance of over 5 km occurred in spring and the averaged floating distance in winter being over 3 km and that in autumn being over 2 km.In summer the longitudinal floating is affected by the large scale circulation which causes a northward floating with the maximum distance of 1 km reached below 200 hPa and southward floating is predominated above 200 hPa instead with the farthest distance of 3 km reached.The latitudinal floating is mainly eastward with the maximal floating distance of over 77 km in winter and the minimal floating distance of near 13 km in summer as well as the intermediate distances of 49 km in spring and of 46 km in autumn.The latitudinal floating dimensions are far bigger than those of the longitudinal floating with the yearly average latitudinal floating of near 60 km and the yearly average longitudinal floating of near 3.5 km.As a result,the latitudinal floating is dominant.There exists an increasing trend of floating distances from the lower to higher levels with the floating dimensions extended westwards with the increasing height.As a whole,the floating dimensions are large and the distribution is more uniform.Also in this paper,the study for the case of typical low-level jet stream existence is addressed to analyze balloon floating with the result that the issues related balloon floating are unable to be ignored.