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青藏高原黑碳气溶胶传输及沉降的季节特征模拟分析

韩永翔1孙海波1刘建慧1赵天良1,S. L. Gong2   

  1. 1. 南京信息工程大学, 大气物理学院, 江苏 南京 210044;
    2. Air Quality Research Division,Science & Technology Branch,Environment Canada,Ontario,Toronto,Canada
  • 出版日期:2014-05-17 发布日期:2014-05-17
  • 作者简介:韩永翔(1966 - ), 男, 教授, 主要从事气溶胶与气候变化的研究. E - mail:han - yx66@126. com
  • 基金资助:

    南京信息工程大学科研启动基金(20110304)及国家自然科学基金(4107506;41175093)共同资助

Study on Simulated Seasonal Variations of Black Carbon Aerosol Transport and Depositions over the Tibetan Plateau

HAN Yongxiang1SUN Haibo1 LIU Jianhui1ZHAO Tianliang1,S.L.Gong2   

  1. 1. School of Atmospheric Physics,Nanjing University of Information Science & Technology,Nanjing 210044,China;
    2. Air Quality Research Division,Science & Technology Branch,Environment Canada,Toronto,Ontario,Canada
  • Online:2014-05-17 Published:2014-05-17

摘要:

根据全球气溶胶气候模式 GEM - AQ/EC 的 1995 ~2004 年模拟, 分析了青藏高原大气黑碳气溶胶的来源、 传输及沉降季节特征。研究表明:青藏高原黑碳气溶胶主要来自自由对流层和大气边界层的输送。相对于自由对流层的黑碳输送, 紧邻青藏高原的南亚、 东亚以及东南亚大气边界层的输送更有效, 它形成了青藏高原由北向南、 自西往东黑碳气溶胶浓度和沉降明显递增的基本分布形态。横跨欧亚大陆自由对流层的黑碳气溶胶由西向东向青藏高原的输送全年不变, 夏季输送路径最北但强度最弱, 冬季路径最南而强度最强。大气边界层黑碳气溶胶的输送受控于亚洲季风环流变化, 来自南亚的黑碳气溶胶在春季越过孟加拉湾传输进入高原东南部, 夏季则可翻越喜马拉雅山抵达青藏高原南部腹地;同时我国中部排放的黑碳气溶胶也在东亚夏季风向北扩展中驱动它从东向西往青藏高原东北部传输。从秋季到冬季, 随着夏季风撤退, 南亚黑碳源区向青藏高原传输衰退, 东亚冬季风的反气旋性环流的南侧及西南侧的偏东风携带秋季我国东南部源区和冬季东南亚源区黑碳气溶胶向青藏高原东南部传输。受青藏高原明显的暖湿季和干冷季气候影响, 干湿沉降分别主导了青藏高原冬季和夏季黑碳沉降, 夏季青藏高原黑碳气溶胶沉降总量大多超过 8 ~ 10 kg·km-2 , 在高原东北部的最高值超过 40 kg·km-2 。冬季青藏高原黑碳气溶胶沉降量最低, 大部地区黑碳沉降低于 5 kg·km -2 。青藏高原黑碳沉降的冬夏季节相差约为 2 ~8 倍。

关键词: 黑碳气溶胶, 青藏高原, 气溶胶传输, 干湿沉降, GEM - AQ/EC

Abstract:

Based on simulation of aerosal in 10 years during 1995 -2004 with a global aerosol climate model system GEM - AQ/EC,the seasonal features of transport and depositions of black carbon (BC) aerosol over the Tibetan Plateau (TP) are characterized. The BC - aerosols over the TP were transported in the free troposphere and within the boundary layer,and the BC - transport to the TP was more efficient within the boundary layer from the South,East and Southeast Asian source regions near to the TP,which contributed to the TP - distributions of BC concentrations and depositions with the increasing gradients from west (north) to east (south). The BC -transport across Eurasian continent in the free troposphere with unchanged direction from west to east varied from the weak fluxes with the northward pathway in summer to the strong fluxes with the southward pathway in winter. Governed by the Asian monsoon circulations,the BC - transport to the TP within the boundary layer had the more significant seasonality. The BC - transport from South Asia crossing the Bay of Bengal reached the southeast TP in spring and climbing over the Himalayas entered the interior of south TP in summer. The northward expanded summer monsoon flows in China drove the BC - transport from the central China to northwest TP. Accompanied with the withdrawing of summer monsoon and development of winter monsoon in autumn and winter in South and East Asia,the BC transport from South Asian source to the TP declined,and the east winds on the south and southwest sides of anticyclone circulation in East Asia forced BC - transport from southeast China in autumn and from the southeast Asian sources in winter to the southeast TP. Controlled by the seasonal shift from warm and wet to cold and dry climate over the TP,wet and dry BC - depositions dominated the total BC depositions over the TP in summer and winter, respectively. Over the large TP areas, the total BC depositions in summer exceeded 8 -10 kg/km 2 and the maximum value was more than 40 kg/km 2 in the northeast part,while the total BC - depositions in winter dropped to less than 5 kg/km 2 . The total BC - depositions over the TP fluctuated seasonally with 2 -8 times between the maximum in summer the minimum in winter.

Key words:  black carbon aerosol, Tibetan Plateau, aerosol transport, dry and wet depositions, GEM - AQ/EC

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