学术
东亚强对流云的季节变化及其与对流层顶关系初探
王旻燕[1,2,3] 吕达仁[1]
[1]中国科学院大气物理研究所中层大气和全球环境探测开放实验室,北京100029 [2]中国科学院研究生院,北京100049 [3]中国气象局国家气象信息中心,北京100081
摘 要:
利用GMS5／VISSR长波红外（10．5～11．5μm）和水汽通道（6．5～7．0μm）探测原理的差异，结合红外阈值法和区域平滑滤波技术提取“高、厚、密”强对流云，分析了东亚强对流云活动的空间分布及其季节变化规律。GMS5卫星视场内各个子地区强对流云云顶温度与发生频率的季节变化基本为单峰单谷型，前者夏低冬高，但不同地区引起的原因不同。强对流云发生频率36°N以北夏低冬高，以南夏高冬低。东亚对流层顶由冬春至夏秋升高，对流层顶气压随之降低，而对流层顶温度的季节变化以45°N为界，北部夏高冬低，南部夏低冬高。作者所研究的东亚几个子地区强对流云与对流层顶季节变化位相基本保持同步，2000年强对流云云顶温度与对流层顶温度的月均值相关系数达0．757，强对流云云顶温度与对流层顶气压的月均值相关系数达0．901，对流层顶温度比强对流云云顶温度平均低9．42℃。强对流云的发展受对流层顶制约作用显著。[著者文摘]
文章出处:
《大气科学》-2007年31卷5期 -937-949页
分 类 号:
文献标识码:
A
文章编号:
1006-9895（2007）05-0937-13
Preliminary Analysis on Seasonal Variation of Deep Convective Clouds and Its Association with the Tropopause in East Asia
WANG Min-Yan, LU Da-Ren（1. Laboratory for Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 ;2. Graduate University of Chinese Academy of Sciences, Beijing 100049 ;3. National Meteorological Information Center, China Meteorological Administration, Beijing 100081）
Abstract:
An algorithm to detect ＂high, thick, dense＂ Deep Convective Clouds （DCCs） is applied in this paper, which makes use of the difference between the infrared channel （10. 5 - 11.5μm） and water vapor channel （6.5 - 7. 0 μm） of VISSR （Visible and Infrared Spin Span Radiometer） on board of GMS 5 and combines with infrared threshold method and segment smoothing filtering algorithm. The seasonal variations of DCCs top temperature and its occurrence frequency in several sub-regions of East Asia are that there are one peak and one dip in a year. DCCs top temperature is lower in summer than in winter in different sub-regions but the reasons are distinct. To the north of 36°N, DCCs are more frequent in winter than in summer, while in the south, the reverse is true. From winter, spring to summer, autumn, tropopause pressure decreases with ascending tropopause height, while tropopause temperature has a pattern of ＂warmer in summer - colder in winter＂ to the north of 45°N and it is reverse to the south. In the focused study areas, DCCs and tropopause keep the similar phase of seasonal variation. In 2000, the correlation of seasonal variations between DCCs top temperature and tropopause temperature reaches 0. 757, and the correlation of seasonal variations between DCCs top temperature ture is 9.42℃, which is lower than DCCs top temperature and tropopause pressure is 0. 901. Tropopause temperaaveragely. Obviously, deep convective activities are restrained strongly by tropopause.[著者文摘]
Key words:
GMS 5, deep convective clouds （DCCs）, cloud top temperature, tropopause, seasonal variation
基金资助:
国家自然科学基金资助项目40333034,科技部基础预研专项2001CCA02200 致谢北京大学物理学院大气科学系毛节泰教授提供了GMS5卫星资料和进行晴云检测的时空判断法.东亚地区对流层顶数据由国家气象信息中心气象资料室提供.与空军第七研究所白洁博士、中国科学院大气物理研究所陈泽宇博士就强对流云提取算法、强对流云与对流层顶关系进行的讨论使本人受益匪浅.特此致谢.
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