摘要
利用FNL再分析资料,统计2008—2012年入海发展江淮气旋并根据气旋不同深厚程度及季节特征分为:暖季深厚型、暖季浅薄型、冬季浅薄型和春初底层型。各类气旋的统计及合成分析表明四类气旋入海基本特征为:入海路径可分为东路和东北路;冬季与初春气旋入海发展增强幅度大于暖季;不同深厚气旋入海后均有下垫面摩擦力减小近海面风力增强,大风区扩大且由气旋偏东位置向东南偏移;暖季气旋入海降水强度增幅明显,并与气旋深厚程度成正比,冬季及春初气旋入海后降水增幅小,春初气旋后部有零散强降水。对入海发展机制的合成诊断显示,气旋中凝结潜热释放对暖季气旋起重要作用,并与气旋深厚程度成正比,对冬季气旋也有正贡献,但对春初底层型气旋无明显作用。春初底层型对海面动力热力影响更敏感,入海后正涡度区的垂直伸展较其它型更显著。而有利于气旋加深的上空辐散中心位置高度与气旋的深厚程度成正比。气旋入海发展中环境因子分析显示,下垫面非绝热加热对冬季和初春气旋作用显著,对暖季气旋影响不明显。高空急流动量下传与下垫面摩擦减弱促使各类气旋增强。湿位涡对暖季气旋有重要正贡献,对深厚气旋作用更强。冬季和初春风场的惯性稳定度和切变稳定度的共同作用有利于气旋增强。1 000 h Pa上湿斜压项MPV2显示的气旋区域温湿锋区位置及强度与入海气旋雨区及雨强对应较好,具有显著指示性。
Using the FNL reanalysis data, the Jianghuai valley cyclones that move to the sea and develop up on the sea during 2008 to 2012 are studied. The cyclones are divided into four categories according to their depths and their living seasons： the warm season deep type, the warm season shallow type, the winter shallow type and the early spring bottom type. The basic characteristics of the cyclones are shown by statistical analysis and composite analysis： their moving paths on the sea mainly are either eastward or northeastward. Their strengthening including intensity and size is larger during winter and early spring than in the warm season. As the underlying surface friction reducing over the sea, the different type and deep cyclones all show that wind speed increasing, large wind area extending, and the location of the large wind area moving to the southeast part of the cyclones. The warm-season deep cyclones on the sea is with a significant increase in precipitation intensity and the increase is proportional to the cyclone depth. For the winter and early spring cyclones, however, their precipitation is slightly enhancing over the sea and there is some scattered strong rainfall at the back part of the early-spring cyclones. The synthetic diagnosis of the cyclone development mechanism over the sea shows that condensation latent heat release plays an important role in the development of the warm season cyclones, the action is proportional to the cyclone depth; the action also provides a positive contribution to the development of winter shallow cyclones, but it is no obvious contribution to the development of early-spring bottom cyclones. The early-spring bottom cyclones are sensitive to the sea surface dynamic and thermal effect, their vertical stretching of vorticity is more significant than other types. The height of the divergence center which is advantageous to the development of the cyclone is proportional to the cyclone depth for all types. The analysis on environment factors of the cyclone development over
出处
《热带气象学报》
CSCD
北大核心
2015年第6期744-756,共13页
Journal of Tropical Meteorology
基金
国家自然科学基金面上项目(41276033)
国家科技支撑项目(2012BAH05B01)
气象公益性行业专项(201206068)
中国气象局气候变化专项江苏气候变化评估(CCSF201318)
江苏科技支撑项目(BE2012774、BE2014729)
江苏高校优势学科建设工程资助项目(PAPD)共同共同资助
关键词
天气学
入海江淮气旋
合成分析
天气特征
结构特征
环境因子
synoptics
Jianghuai Valley cyclones over the sea
composite analysis
weather characteristics
structural characteristics
environmental factors
