摘要
青藏高原西部,尤其是西南部阿里地区异常高的古湖岸线揭示出,这一区域可能存在中全新世的异常高降水中心。基于此,本文利用WorldClim数据集资料对中全新世和现代降水进行对比,并使用ERA5数据初步探讨了出现异常高降水的可能机制。结果显示,青藏高原西部中全新世降水远比现代高,尤其是西南部出现了相对的高降水中心。现代青藏高原西南部降水增加时,对应印度夏季风增强,印度次大陆低空对流层低压中心增强,深对流的发生更为频繁,导致向高原西南部输送的水汽增强。与此同时,印度北部降水增加导致的凝结潜热释放增加会使南亚高压增强并向西北方向移动,导致青藏高原西南部上升运动加强,从而导致青藏高原西南部降水增加。相对于现代,中全新世印度季风较强,位于印度次大陆低空的低压可能更强,印度北部的凝结潜热释放也会加强,进而导致中全新世青藏高原西南部出现异常高降水。
The ancient lake shorelines in the western Qinghai-Xizang(Tibet)Plateau reveals that there may be more precipitation than present day(PD)during the mid-Holocene(MH),especially in the Ngari. Thus,we compared the precipitation between the MH and the PD using the high-resolution precipitation of the WorldClim dataset and then applied the ERA5 dataset to explore the underlying mechanisms of the precipitation over the southwestern Qinghai-Xizang(Tibet)Plateau. The results show that precipitation in the MH over the western QinghaiXizang(Tibet)Plateau was much higher than that in the PD,with the strongest precipitation occurring over the southwestern Qinghai-Xizang(Tibet)Plateau. When the precipitation over the southwestern Qinghai-Xizang(Tibet)Plateau enhanced in the PD,the Indian summer monsoon(ISM)also strengthened. The enhanced ISM could strengthen low pressure in the lower troposphere and deep convection over the Indian subcontinent. These could increase the water vapor transport to the southwestern Qinghai-Xizang(Tibet) Plateau. Meanwhile,the increased condensation latent heat released by the increased precipitation over northern India enhanced and northwestward moved the South Asian High,leading to the increased ascending motion and precipitation over the southwestern Qinghai-Xizang(Tibet)Plateau in the PD. Compared with PD,the ISM during the MH was stronger,and the low pressure over the Indian subcontinent may be stronger. The related condensation latent heat may also increase,which could further result in the increased precipitation over the southwestern Qinghai-Xizang(Tibet)Plateau during the MH.
作者
黄凌昕
张帅
陈婕
黄伟
阳坤
陈发虎
HUANG Lingxin;ZHANG Shuai;CHEN Jie;HUANG Wei;YANG Kun;CHEN Fahu(Key Laboratory of Western China's Environmental Systems(Ministry of Education),College of Earth and Environmental Sciences,Lanzhou Universitys Lanzhou 730000,Gansu,China;Group of Alpine Paleoecology and Human Adaptation,Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;State Key Laboratory of Tibetan Plateau Earth System,Resources and Environment,Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;Department of Earth System Science,Tsinghua University,Beijing 100101,China;National Tibetan Plateau Data Center,Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China)
出处
《高原气象》
CSCD
北大核心
2021年第6期1407-1418,共12页
Plateau Meteorology
基金
国家自然科学基金项目(41988101)
第二次青藏高原综合科学考察研究项目(2019QZKK0601)。
关键词
中全新世
青藏高原西南部
印度夏季风
降水变化机制
Mid-Holocene
the southwestern Qinghai-Xizang(Tibet)Plateau
Indian summer monsoon
mechanisms for precipitation changes
