中国科学院地质与地球物理研究所吕厚远及其团队报道了近两千年来青藏高原湖相层压花粉记录的雨季跨度和降水时空变化。该研究于2024年2月20日发表于国际一流学术期刊《中国科学：地球科学》杂志上。

研究人员通过确定降水拐点，确定了高原不同地区雨季的起止时间。通过计算雨季的持续时间和降水量，研究建立了现代花粉组合与它们之间的传递函数。在此基础上，研究人员重建了库赛湖(青藏高原北部)和Jiang Co(青藏高原中部)近2000年的雨季变化。结果表明，库赛湖的雨季降水记录出现了5个高降时段：分别为AD 580-680，1000-1100，1200-1450，1550-1780，1920至今，对应着较长的雨季时段。

江错雨季降水序列记录了4个高降水时段：AD80-500、800-950，1250-1450，1780年至今，与AD 1000年之前的长雨季一致，但之后不明确。从空间上看，高原雨季降水呈现四种模式，“南北偏湿”的特征可能与异常强烈的夏季风有关；“南北干燥”可能与西风减弱和夏季风减弱有关；“南湿北干”与夏季风强、西风弱有关；“南干北湿”与夏季风弱和西风强有关。该研究揭示了近2000年来青藏高原雨季的起止、持续时间和降水量的时空演变模式。为进一步认识西风与亚洲夏季风的耦合关系提供了自然背景支持。

据介绍，青藏高原雨季长度和降雨量的定量重建对于揭示西风带和亚洲夏季风的时空演变，及其生态环境效应具有重要意义。准确地确定高原雨季的开始和结束时间仍然具有挑战性。

附：英文原文

Title: Spatiotemporal variation of rainy season span and precipitation recorded by lacustrine laminated pollen in the Tibetan Plateau during the past two millennia

Author: Anning CUI, Houyuan LU, Juzhi HOU, Xingqi LIU, Deke XU

Issue&Volume: 2024/02/20

Abstract: The quantitative reconstruction of the length of the rainy season and precipitation on the Tibetan Plateau (TP) is crucial for revealing the spatiotemporal evolution of the Westerlies and Asian summer monsoon, as well as its ecological and environmental effects. Accurately determining the start and end times of the rainy season on the Plateau remains challenging. This study determined the start and end times of the rainy season in different locations on the Plateau by identifying precipitation inflection points. We calculated the duration and precipitation amount of the rainy season and established a transfer function between the modern pollen assemblages and them. Then, we reconstructed the rainy season variations in Kusai Lake (northern TP) and Jiang Co (central TP) during the past two millennia. The results showed that, the rainy season precipitation in Kusai Lake recorded five periods of high precipitation: AD 580–680, 1000–1100, 1200–1450, 1550–1780, and 1920–present, corresponding to the stages with long rainy season. The rainy season precipitation sequence in Jiang Co recorded four periods of high precipitation: AD 80–500, 800–950, 1250–1450, and 1780–present, which is consistent with the long rainy season before AD 1000 but unclear afterward. Spatially, rainy season precipitation on the Plateau exhibited four patterns: “wet in both north and south” may be related to abnormally strong summer monsoons; “dry in both north and south” likely associated with weak Westerly wind and weak summer monsoon; “wet in the south and dry in the north” linked to strong summer monsoon and weak Westerly wind; and “dry in the south and wet in the north” connected to weak summer monsoon and strong Westerly wind. This study revealed the spatiotemporal evolution pattern of the rainy season onset and end, duration, and precipitation amount on the Plateau over the past two millennia. It provides natural background support for further understanding the coupling between Westerly wind and Asian summer monsoon.

DOI: 10.1007/s11430-023-1255-3

Source: https://www.sciengine.com/10.1007/s11430-023-1255-3