Collaborative Research: Past and Present Climatic Controls on the Stable Isotope Composition of Precipitation at Low Latitude Proxy Sites

这一奖项有助于建立在研究人员之前由美国国家科学基金会资助的关于低纬度替代地点降水中稳定水同位素(即三角洲18氧、三角洲氚)的气候控制研究的基础上。研究人员的主要科学目标是评估现代世界和过去对不同低纬冰芯位置(即热带安第斯山脉、西藏、喜马拉雅)稳定同位素变异性的控制。这将有助于解决围绕从热带冰芯得出的古气候记录的解释的一些争议。具体研究目标包括：-调查现代气候控制，如温度、降水量效应、水汽来源可变性和大气环流对热带冰芯稳定同位素的影响，并分析厄尔尼诺-南方涛动(ENSO)或亚洲季风强度等气候模式对稳定同位素可变性的影响，-分析轨道参数变化(中全新世条件)对与热带冰芯有关的稳定同位素分布和潜在气候控制的影响，-通过制定新的和更现实的热带冰川海温(SST)数据重建方案，调查末次冰期最大值(LGM)边界条件对低纬稳定同位素分布的影响。--探索利用热带冰芯中过量的氢作为改进热带海洋条件重建的额外气候指标，以及-通过将模拟结果与现有的替代数据以及与国际原子能机构-全球降水同位素网络(IAEA-GNIP)和国家环境预测中心-国家大气研究中心(NCEP-NCAR)现代实验的再分析数据进行比较，进行模型评估。所有实验都将基于GISS II(北纬4度x经度5度，对安第斯山脉的地形控制进行了新的改进)模型和欧洲中心-汉堡ECHAM-4(T30和T106光谱分辨率)模型。这项研究将提供对古气候记录的更好理解，这些记录被用来帮助理解自然气候变异性与人类对气候的影响相比较。这项研究产生的数据和模型输出将通过世界古气候学数据中心-A提供给更广泛的科学界。

This award helps build upon the researchers' previously NSF-funded research on the climatic controls on stable water isotopes (i.e., delta 18-Oxygen, delta Deuterium) in precipitation at low latitude proxy sites. The researchers' main scientific goal is to evaluate the controls on stable isotope variability at various low latitude ice core locations (i.e., Tropical Andes, Tibet, Himalaya) in the modern world and in the past. This will help to resolve some of the controversy surrounding the interpretation of paleoclimate records derived from tropical ice cores. Specific research goals include:-- investigating the modern climatic controls such as temperature, precipitation volume effect, moisture source variability and atmospheric circulation on stable isotopes at tropical ice core sites and analyzing the influence of climate modes such as El Nino-Southern Oscillation (ENSO) or Asian monsoon intensity on stable isotope variability,-- analyzing the influence of changed orbital parameters (mid-Holocene conditions) upon stable isotope distribution and potential climatic controls related to tropical ice cores,-- investigating the effect of Last Glacial Maximum (LGM) boundary conditions upon low latitude stable isotope distribution by prescribing new and more realistic reconstructions of glacial tropical sea surface temperature (SST) data,-- exploring the use of the Deuterium excess in tropical ice cores as an additional climate proxy for improved reconstructions of tropical oceanic conditions, and-- performing model evaluation by comparing the simulated results with the available proxy data and with International Atomic Energy - Global Network of Isotopes in Precipitation (IAEA-GNIP) and National Center for Environmental Prediction - National Center for Atmospheric Research (NCEP-NCAR) reanalysis data for the modern experiments.All experiments will be based on the GISS II (4 degrees latitude x 5 degrees longitude, with new improved topographic control over the Andes) model and the European Center-Hamburg ECHAM-4 (T30 and T106 spectral resolution) models. This research will provide improved understanding of paleoclimatic records that are used to help understand natural climate variability compared to anthropogenic influences on climate. The data and model output resulting from this research will be made available to the wider scientific community through the World Data Center-A for Paleoclimatology.