Isotope Dendroclimatology in Tropical Asia

该奖项支持使用同位素树状气候学研究热带海洋和全球尺度大气环流过程在季节到年度间的相互作用。同位素树状气候学是一种从树木细胞中提取稳定同位素测量的新的和不断发展的研究工具。具体地说，研究人员和他的同事将利用同位素树状气候学对过去几个世纪亚洲热带地区的降雨量变异性进行年度可分辨的代理估计。这些数据将被用来研究区域降雨模式(包括干旱循环)与更广泛的气候变异性模式之间的关系，例如厄尔尼诺南方涛动(ENSO)、亚洲季风和太平洋年代际变率。这位研究人员和他的同事已经用哥斯达黎加、印度尼西亚和泰国的树木展示了这种新方法的潜力，现在将把这项研究扩展到亚洲各地热带森林工作的几个不同研究小组收集的样本。研究人员和他的同事将把他们的努力集中在东南亚季风和ENSO上，以更好地了解热带地区气候变化在季节、年际和年代尺度上的自然模式，从而提高科学界预测气候变化对人类社会和自然生态系统影响的能力。古气候学领域最近的许多知识进步都归功于来自树木年轮的数据。然而，树木年轮研究领域主要局限于收集中高纬度地区的数据，因为在这些地区，由于季节性的温度和降水的差异，树木会形成生长带状。一般来说，对于热带地区，季节性被广泛地描述为相对潮湿和干燥。随着时间的推移，这些环境因素与植物学的进化共同创造了一种情况，在这种情况下，树木不会轻易放弃使用传统的生长分析视觉方法可能拥有的气候信息，因为并不是所有的热带树木都会产生明显的生长带。这给古气候学家带来了一些问题，因为热带地区覆盖了地球上很大的一片区域，而他们拥有的气候数据几乎没有被利用，因为树木还没有作为数据档案。这项研究有望打开这一档案，进行量化分析。

This award supports research to examine the interplay of tropical oceans and global-scale atmospheric circulation processes at seasonal to inter-annual time scales using isotope dendroclimatolgy, a novel and evolving investigative tool for extracting stable isotope measurements from tree cellulose.Specifically, the researcher and his colleagues will develop annually resolved proxy estimates of rainfall variability from tropical Asia for the past several centuries using isotope dendroclimatology. The data will be used to examine relationships between regional rainfall patterns (including drought cycles) and broader patterns of climate variability such as the El Nino Southern Oscillation (ENSO), the Asian monsoon, and Pacific decadal variability). The investigator and his colleagues have demonstrated the potential of this new approach using trees from Costa Rica, Indonesia, and Thailand and now will expand this research to samples collected by several different research teams working in tropical forests throughout Asia.The researcher and his colleagues will focus their efforts on the monsoons of Southeast Asia and ENSO to better understand the natural patterns of climate variability in the tropics at seasonal, inter-annual, and decadal scales thereby improving the scientific community's abilities to predict the effects of climate variability on human society and natural ecosystems.The field of paleoclimatology owes many of its recent strides in knowledge to data derived from tree rings. However, the field of tree ring research has been primarily limited to collecting data from the mid to high latitudes because in these regions, trees develop growth banding due to differences in temperature and precipitation as a result of seasonality. In general for the tropical regions, seasonality is broadly described as relatively wet and dry. Such environmental factors have conspired with botanical evolution over time to create a situation in which the trees do not readily give up the climate information they may possess using the traditional visual methods of growth analyses because not all tropical trees create obvious growth bands. This has created something of a problem for paleoclimatolgists because the Tropics cover a significant area of the Earth yet the climate data they possess has barely been tapped because trees have not been available as a data archive. This research holds the promise of opening up that archive to quantitative analysis.