北京大学学报(自然科学版)

我国副热带地区夏季深对流活动气候分布特征

郑永光1,2,王颖3, 4,寿绍文4   

  1. 1. 国家气象中心, 北京 100081; 2. 中国气象局武汉暴雨研究所,武汉 430074; 3. 浙江省气象服务中心, 杭州 310017; 4. 南京信息工程大学,南京 210044;
  • 收稿日期:2009-09-14 出版日期:2010-09-20 发布日期:2010-09-20

Climatology of Deep Convection over the Subtropics of China during Summer

ZHENG Yongguang1,2, WANG Ying3, 4, SHOU Shaowen4   

  1. 1. National Meteorological Center, Beijing 100081; 2. Institute of Heavy Rain Research of CMA, Wuhan 430074; 3. Meteorological Service Center of Zhejiang Province, Hangzhou 310017; 4. Nanjing University of Information Science and Technology, Nanjing 210044;
  • Received:2009-09-14 Online:2010-09-20 Published:2010-09-20

摘要: 利用1996?2007年(无2004 年) 11 年 6?8 月具有较高时、空分辨率与很好时、空完整性的静止卫星红外亮温(TBB) 资料, 给出了我国副热带地区(94 °?124 °E, 24 °?36°N) 夏季的深对流活动气候分布特征。该地区夏季深对流活动存在 3 个活跃中心: 青藏高原东部的川西高原及云南北部部分区域, 云贵高原东北部的云南、贵州交界区域以及广西北部区域, 浙江、福建与江西大部区域。深对流活动与地势分布、东亚夏季风和大气环流密切相关,不同区域的深对流活动具有不同的月际和候际变化特征, 深对流活动具有显著的间歇性发展特征。江淮流域的候变化特征清楚地反映了该区域的梅雨期降水和二度梅降水。深对流活动 日变化演变表 明川西高原、云贵高原、浙闽地区等不同地区的深对流活动具有不同的传播特征。这种深对流活动的日变化传播特征与区域地势分布密切相关。我国副热带地区存在单峰型和双峰型两类 日变化特征深对流, 但不同地区同类型日变化深对流也具有不同的日变化特点。川西高原、云贵高原与浙闽地区深对流日变化都为单峰型, 但川西高原与云贵高原深对流 比浙闽地区持续活跃时间更长。四川盆地东部、江淮流域、湖南与广西区域都属于双峰型深对流活动区域, 但 四川盆地东部深对流活动主峰在 日出前( 22 UTC) , 不同于江淮流域、湖南与广西在 日落时段( 09?10 UTC) 的深对流活动主峰。

关键词: 我国副热带, 气候分布, 深对流, 日变化

Abstract: Due to the finer temporal and spatial resolution and the better integrality of long-term satellite infrared (IR) temperature of black body (TBB) data, a climatology of deep convection over the subtropics of China( 94 °-124 °E, 24 °-36°N) during summer is presented based on the 1-hourly IR TBB data during June to August of 1996-2007 (2004 excluded). The results show that the climatological characteristics of deep convection denoted by TBB≤ - 52℃ over the subtropics of China are basically consistent with those previous statistical studies based on the surface thunderstorm observations and the low-orbit satellite lightning observations. The monthly variations, pentad variations and diurnal variations of the deep convection over the subtropics of China are focused on. The results show that there are 3 active deep convection areas in the subtropics of China during the period of June-August: Plateaus of Western Sichuan, northeast Yunnan-Guizhou Plateaus, and Zhejiang-Fujian-Jiangxi areas. The monthly variations of the deep convection over the subtropics of China are closely associated with the East Asia Monsoon and the large-scale atmospheric circulation. The deep convection is more active in June and July than in August. The development of the deep convection over the subtropics of China has a characteristic of intermittence, and the active pentad period of the deep convection over the Yangtze-Huaihe River Basin clearly reflects the rainfall events during the Meiyu period and the secondary Meiyu period. The diurnal evolution of the deep convection shows that the deep convection over the Plateaus of Western Sichuan propagates southeastwards after sunset, and then propagates northeastwards to the east Sichuan Basin after midnight, the deep convection over the northeast Yunnan-Guizhou Plateaus propagates southeastwards to north Guangxi after sunset, and the deep convection over Zhejiang-Fujian areas extends westwards and northwards at sunset and retreats eastwards and southwards after sunset. This characteristic of the diurnal variations of the deep convection is, to a great extent, determined by the local topographic distribution. The diurnal variations of the deep convection over the subtropics of China also show that there are two types of diurnal variations of deep convection: single-peak convection and double-peak convection. The diurnal variations of the deep convection over Plateaus of Western Sichuan, Yunnan-Guizhou Plateaus, and Zhej iang-Fujian areas have one peak, but the active period over Plateaus of Western Sichuan and Yunnan-Guizhou Plateaus is much longer than that over Zhejiang-Fujian areas, and the frequency of the deep convection over Yunnan-Guizhou Plateaus in the active period changes much slower than that over the other two areas. The diurnal variations of the deep convection over eastern Sichuan Basin, the Yangtze-Huaihe River Basin, Hunan and Guangxi have two peaks, but the main deep convection peak over eastern Sichuan Basin is before sunrise ( 22UTC) and different from that over the other 3 areas at sunset (09-10 UTC) , and the amplitude of the diurnal deep convection variation over the Yangtze-Huaihe River Basin is much smaller than that over the other 3 areas.

Key words: subtropics of China, climatology, deep convection, diurnal variations

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