Reconstructing Monsoon and Climate Variability from Naimona'nyi Ice Cores, Southwest Himalayas

该项目资助从西藏喜马拉雅西部的Naimona'nyi冰原（30 - 27.06N; 810 - 19.94' E，海拔6100米）中恢复两个冰芯到基岩，并为该数据稀疏的地区生成长、高分辨率的多代理气候历史，包括季风变率。Naimona’nyi冰原所处的气候条件与青藏高原（TP）前4个冰芯所处的气候条件明显不同。这片冰原夏季和冬季降雪量几乎相等。夏季降水通过夏季风环流从阿拉伯海到达，而冬季降水通过冬季西风气旋形成从更多的大陆来源到达。因此，将Naimona'nyi气候和降水历史与同期以季风降水为主的大索普冰川记录相结合，将产生更可靠、更清晰的冬季降雪变率和阿拉伯海表面温度（SSTs）记录，从而得到影响南亚人口稠密地区的季风变率记录。该项目有四个关键的科学目标：(1)利用氧和氘同位素、主要离子化学和不溶性尘埃测量重建温度、干旱和大气环流模式的高分辨率记录；(2)将这些记录与喜马拉雅地区的其他古气候历史相结合，重建夏季季风降雪和冬季西风气旋风暴降水的变率，并以年至年代际分辨率来识别气候突变；（三）编制地区火灾史；(4)确定在干燥的西喜马拉雅地区是否存在更古老的（前全新世）冰期冰。奈莫纳尼岛上的58个冰川曾经覆盖的面积是现在的10倍，这表明喜马拉雅山脉西部的气候曾经湿润得多。这项研究的预期记录，以及其他来自高纬度和低纬度的千年尺度记录，将有助于确定低纬度冰川开始的时间，目前假设低纬度冰川是由进动驱动的和非同步的。今天，越来越多的证据表明，整个热带地区正在发生强烈的变暖。在过去的24年里，中国46298座冰川的体积减少了5%，相当于损失了3000多公里的冰。自1990年以来，撤退速度明显加快。Naimona'nyi预计的冰芯记录，加上该地区的当代观测，将进一步加深气候科学界对气候因素的理解，这些气候因素控制着喜马拉雅西部这些冰原最近的质量损失。该项目体现了中国科学院青藏高原研究所（ITPR）和美国俄亥俄州立大学伯德极地研究中心（OSU-BPRC）在科学研究和文化交流方面的强有力的国际合作。

This project funds the recovery of two ice cores to bedrock from the Naimona'nyi ice field (30o 27.06N; 81o 19.94' E, 6100 meters above sea level) in the western Tibetan Himalayas and to produce a long, high resolution multi-proxy climate history, including monsoonal variability, for this data-sparse region.The Naimona'nyi ice field is in a distinctly different climate regime from the four previous ice cores recovered from the Tibetan Plateau (TP). This ice field receives nearly equal amounts of summer and winter snowfall. Summer precipitation arrives from the Arabian Sea via the summer monsoon circulation while winter precipitation arrives from more continental sources via winter westerly cyclogenesis. Thus, integration of the Naimona'nyi climate and precipitation histories with contemporaneous records from Dasuopu Glacier, dominated by monsoonal precipitation, will yield more robust and better resolved records of winter snowfall variability and Arabian sea surface temperatures (SSTs) and thus of monsoonal variability that affects highly populated areas of southern Asia. This project has four key scientific goals: (1) to reconstruct high resolution records of temperature, aridity and atmospheric circulation patterns using isotopes of oxygen and deuterium, major ionic chemistry, and insoluble dust measurements; (2) to integrate these records with other paleoclimate histories from the Himalayas to reconstruct the variability of both summer monsoon snowfall and winter precipitation from westerly cyclogenic storms with annual to decadal resolution required to discern abrupt climate changes; (3) to produce a regional fire history; and (4) to determine if older (pre-Holocene) glacial stage ice exists in the dryer western Himalayas.The fifty-eight glaciers on Naimona'nyi once covered an area ten times greater than today, suggesting that the climate in the western Himalayas was once much wetter. The anticipated records from this research, along with other millennial-scale records from both high and low latitudes, will help establish the timing of the onset of low latitude glaciation that is currently hypothesized to be precession driven and asynchronous. Today, evidence is accumulating for an ongoing strong warming throughout the tropics. During the last twenty-four years, the volume of China's 46,298 glaciers has decreased five percent, equivalent to a loss of more than 3,000 km of ice. There has been a notable acceleration in retreat rates since 1990. The ice core records anticipated from Naimona'nyi, coupled with contemporary observations in the region, will further the climate science community's understanding of the climatic factors controlling the recent loss of mass from these ice fields in the western Himalaya.The project presents a strong international collaborative effort between the Institute for Tibetan Plateau Research (ITPR) of the Chinese Academy of Sciences (CAS) and the Ohio State University Byrd Polar Research Center (OSU-BPRC) in scientific research and cultural exchange.