| 青藏高原抬升加热气候效应研究的新进展 |
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| 引用本文： | 吴国雄,刘新,张琼,钱永甫,毛江玉,刘屹岷,李伟平.青藏高原抬升加热气候效应研究的新进展[J].气候与环境研究,2002,7(2):184-201. |
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| 作者姓名： | 吴国雄 刘新 张琼 钱永甫 毛江玉 刘屹岷 李伟平 |
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| 作者单位： | 1. 中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京,100029
2. 南京大学大气科学系系,南京,210093 |
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| 基金项目： | 国家重点基础研究发展规划项目G1998040900,中国科学院重要方向创新项目ZKCX2-SW-210和国家自然科学基金资助项目40135020、40023002,49905002及40005006 |
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| 摘 要： | 对近4年来关于青藏高原加热影响气候的研究进行回顾.首先介绍利用位涡方程和热力适应理论,揭示;夏季高原上空低层气旋式及高层反气旋式环流结构稳定维持的动力学机理.结果表明高原加热作用造成的低层正涡源是低层气旋式环流得以稳定维持的重要原因.而边界层摩擦产生的负位涡是平衡正位涡的主要因素.高原加热还在高原上空形成负位涡,它影响着盛夏的大气环流,是青藏高原上空强大而稳定的反气旋环流得以维持的重要因素.在春夏过渡季节青藏高原非绝热加热对大气环流季节变化以及亚洲季风爆发的影响力方面,进一步确认了感热加热在过渡季节早期(5月中旬以前)环:流演变中的重要作用.青藏高原非绝热加热的时间演变引起了海陆热力差异对比的变化,使副热带高压带首先在孟加拉湾东部断裂,亚洲季风因而在孟加拉湾爆发.结果还表明,用纬向风垂直差异的时空分布能更准确地表示季节变化的区域差异.在青藏高原非绝热加热与北半球环流系统年际变化的联系方面,发现夏季青藏高原的加热强(弱)的年份,高原感热加热气泵(SHAP)高(低)效工作,使高原加热对周边地区低层暖湿空气的抽吸效应和对高层大气向周边地区的排放作用加强(减弱),高原及邻近地区的上升运动,下层辐合和上层辐散均增强(减弱),从而影响着高原和周边地区的环流以及亚洲季风区大尺度环流系统.而且高原的加热强迫还能够激发产生一支沿亚欧大陆东部海岸向东北方向传播的Rossby波列,其频散效应可影响到更远的东太平洋以至北美地区的大气环流.研究还表明,盛夏的南亚高压存在"青藏高压型"和"伊朗高压型"的双模态,它们与高原加热状态有关,且显著地与亚洲季风区的气候分布密切联系.
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| 关 键 词： | 高原加热 环流维持 季节转化 年际变化 南亚高压 |
| 修稿时间： | 2002年2月28日 |
Progresses in the Study of the Climate Impacts of the Elevated Heating over the Tibetan Plateau |
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| Wu Guoxiong,Liu Xin,Zhang Qiong,Qian Yongfu,Mao Jiangyu,Liu Yimin and Li Weiping.Progresses in the Study of the Climate Impacts of the Elevated Heating over the Tibetan Plateau[J].Climatic and Environmental Research,2002,7(2):184-201. |
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| Authors: | Wu Guoxiong Liu Xin Zhang Qiong Qian Yongfu Mao Jiangyu Liu Yimin and Li Weiping |
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| Abstract: | The progresses of study of the climate impacts of the Tibetan Plateau heating over the past lour years arc reviewed. Firstly, based on the potential vorticity (PV) equation and the theory of therm al adaptation, the mechanism for the formation and maintenance of the circulations over the Tibetan Plateau in summer are explored. Result shows the positive PV that is produced by heating near the sur face is balanced by the frictional dissipation, and the negative PV that is generated by heating in the up per layers over Tibetan Plateau is balanced by the divergence of negative PV. It is further substantiatedthat the sensible heating plays important roles in the seasonal transition of atmospheric circulation from winter to summer and in the Asian monsoon onset. The evolution of diabatic heating over the Tibetan Plateau causes the variation in land-sea thermal contrast, and results in the earliest breaking of the subtropical anticyclone belt and Asian monsoon onset over the eastern Bay of Bengal. The results also suggest that the spatial and temporal evolution of the vertical shear of zonal wind can better reflect the territorial differences in seasonal variability. The strong (weak) diabatic heating over the Tibetan Pla teau in summer corresponds to the high (low) efficiency of the Sensible Heal driven Air Pump (SHAP) over the plateau, and result in strong (weak) divergence in the upper troposphere and convergence in the lower troposphere. Furthermore, the northeastward propagating Rossby wave train induced by the anomalous heating over the Tibetan Plateau can reach far distance areas. Therefore, the interannual va riability of the diabalic heating over the Tibetan Plateau is closely correlated with that of the in-situ and north hemispheric circulations. Finally, it was reported that in summer, there exists bimodality in the longitude location of the South Asian High in the upper troposphere: the Tibetan mode and Iran mode. Such bimodalily is closely associated with the thermal states of the Tibetan Plateau, and significantly affects the climate anomalies over the Asian monsoon area in summer. |
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| Keywords: | healing over Tibetan Plateau circulation maintenance seasonal transition interannual va riability South Asian High |
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