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

该奖项有助于建立在研究人员之前的nsf资助的研究上，该研究是关于低纬度代理地点降水中稳定水同位素（即δ 18-氧，δ氘）的气候控制。研究人员的主要科学目标是评估现代世界和过去不同低纬度冰芯位置（即热带安第斯山脉、西藏、喜马拉雅）对稳定同位素变化的控制。这将有助于解决围绕热带冰芯古气候记录解释的一些争议。具体研究目标包括：——研究现代气候控制，如温度、降水量效应；水汽源变率和大气环流对热带冰芯稳定同位素的影响，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变率的影响；分析轨道参数变化（全新世中期条件）对稳定同位素分布和与热带冰芯相关的潜在气候控制的影响；研究末次极大期（LGM）边界的影响通过对冰川热带海面温度（SST）数据进行新的和更现实的重建，探索利用热带冰芯中的氘过剩作为改善热带海洋条件重建的额外气候代用物。通过将模拟结果与现有的代理数据以及国际原子能-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）的现代实验再分析数据进行比较，进行模式评估。所有实验将基于GISS II（4度纬度x 5度经度，对安第斯山脉有新的改进的地形控制）模式和欧洲中心-汉堡ECHAM-4 （T30和T106光谱分辨率）模式。这项研究将提供对古气候记录的更好理解，这些记录用于帮助理解自然气候变率与人为对气候影响的比较。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向更广泛的科学界提供。

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.