| 青藏高原夏季地面热源的气候特征及其对高原低涡生成的影响 |
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| 引用本文： | 李国平,卢会国,黄楚惠,范瑜越,张博.青藏高原夏季地面热源的气候特征及其对高原低涡生成的影响[J].大气科学,2016,40(1):131-141. |
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| 作者姓名： | 李国平 卢会国 黄楚惠 范瑜越 张博 |
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| 作者单位： | 1.成都信息工程大学大气科学学院, 成都 610225 |
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| 基金项目： | 国家自然科学基金91337215、41175045,国家重点基础研究发展计划(973计划)项目2012CB417202,公益性行业(气象)科研专项GYHY201206042 |
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| 摘 要： | 根据NCEP/DOE再分析资料的地面感热通量和潜热通量以及MICAPS天气图资料识别的高原低涡资料集,研究了近30年来青藏高原夏季地面热源和高原低涡生成频数的气候学特征,分析了高原地面加热与低涡生成频数的时间相关性及其物理成因.得到如下认知:夏季高原地面感热通量的气候均值为58 W m-2,近30年地面感热总体呈微弱的减小趋势.其中在1980年代初期和21世纪前10年的大部分时段,地面感热呈增大趋势,而中间时段呈波动式下降.地面感热具有准3年为主的周期振荡,1996年前后是其开始减弱的突变点.高原夏季地面潜热通量的气候均值为62 W m-2,近30年呈波动状变化并伴有增大趋势.地面潜热的周期振荡以准4年为主,地面潜热增大的突变始于2004年前后.夏季高原地面热源的气候均值为120 W m-2,其中地面感热与地面潜热对地面热源的贡献在夏季大致相当.地面热源总体呈幅度不大的减弱趋势,其中1980年代到1990年代末偏强,21世纪前6年明显偏弱,随后又转为偏强.地面热源亦呈准3年为主的周期振荡并在1997年前后发生由强转弱的突变.根据MICAPS天气图资料的识别和统计,近30来夏季高原低涡的生成频数整体呈现一定程度的线性减少趋势,低涡高发期主要集中在1980年代到1990年代中后期.低涡生成频数有准7年为主的周期振荡现象,自1990年代中期开始的低涡生成频数的减少态势在1998年前后发生了突变.夏季高原低涡生成频数与同期高原地面感热呈高度正相关,与地面潜热呈一定程度的负相关,但与同期地面热源仍呈较显著的正相关.因此,在气候尺度上,高原地面热源偏强特别是地面感热偏强的时期,对应高原低涡的多发期.本研究从气候统计的时间相关性角度揭示了高原地面加热作用对催生高原低涡乃至高原对流活动的重要性.
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| 关 键 词： | 地—气相互作用 青藏高原 低涡 地面热源 气候特征 |
| 收稿时间： | 2/9/2015 12:00:00 AM |
A Climatology of the Surface Heat Source on the Tibetan Plateau in Summer and Its Impacts on the Formation of the Tibetan Plateau Vortex |
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| LI Guoping,LU Huiguo,HUANG Chuhui,FAN Yuyue and ZHANG Bo.A Climatology of the Surface Heat Source on the Tibetan Plateau in Summer and Its Impacts on the Formation of the Tibetan Plateau Vortex[J].Chinese Journal of Atmospheric Sciences,2016,40(1):131-141. |
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| Authors: | LI Guoping LU Huiguo HUANG Chuhui FAN Yuyue and ZHANG Bo |
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| Institution: | 1.College of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu 6102252.College of Meteorological Observation, Chengdu University of Information Technology, Chengdu 6102253.Sichuan Meteorological Observatory, Chengdu 610072 |
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| Abstract: | Based on NCEP/DOE (National Centers for Environmental Prediction/Department of Energy) reanalysis data of surface sensible heat and latent heat fluxes on the Tibetan Plateau (TP) and datasets of the Tibetan Plateau Vortex (TPV) recognized from MICAPS (Meteorological Information Comprehensive Analysis and Process System) weather maps, this paper studies the near 30-year (1981-2010) climatological characteristics of surface heating and generating frequency of TPVs over the TP in summer, and analyzes the temporal correlation between the TP surface heating and the TPV statistics and its physical cause. The following results are obtained: The climatic average of TP surface sensible heat fluxes in summer is 58 W m-2, showing an overall weak decreasing trend in the near 30-year period. An increasing trend is apparent in the early 1980s and most of the first decade of the 21st century, but a fluctuating decline between. Surface heating shows a quasi-three-year periodic oscillation, and an abrupt climate change starts around 1996. The climatic average of surface latent heat fluxes in summer is 62 W m-2, showing fluctuating changes accompanied by an increasing trend over the near 30-year period. The surface latent heat shows a quasi-four-year periodic oscillation, with an abrupt increase beginning around 2004. The climatic average of the surface heat source in summer is 120 W m-2; sensible heat and latent heat on the ground contributes the same to the surface heat source over the TP in summer. The surface heat source shows a modest weakening trend overall, with a strong phase between the 1990s and 1980s, an obvious weak phase in the first six years of the 21st century, and then becomes strong again. The surface heat source shows a three-year periodic oscillation and an abrupt change from strong to weak around 1997. Based on identification using the MICAPS weather maps, the linear frequency of summer TPVs over the near 30-year period showed a certain degree of decline, with a higher frequency mainly concentrated in the 1980s to 1990s. The generating frequency of TPVs shows a 7-year periodic oscillation, and features an abrupt change around 1998. The generating frequency of TPVs over the same period is highly positively correlated to sensible heat but weakly negatively correlated to latent heat, but compared with the surface heat source over the TP, is still a significant positive correlation. On the climate scale, therefore, stronger periods of TP surface heating, especially surface sensible heating, correspond to the favorable formation of TPVs. From the perspective of the temporal correlation of climate statistics, this study reveals important impacts of the TP surface heating on promoting TPVs and convective activity. |
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| Keywords: | Land-atmosphere interaction Tibetan Plateau Vortex Surface heating Climatic characteristics |
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