Collaborative Research: Pilot Study in Tropical Isotope Dendroclimatology

本研究的科学策略利用稳定同位素树木生态学、质谱学和分析化学的最新突破，开发缺乏年轮的热带树木的年代学和气候代理数据。树木年轮记录在长期观测（500年前或更久）中显示出巨大的潜力，但由于许多热带树种间歇性地或根本不形成年轮，因此其范围有限。这项研究的最终目标是对印度尼西亚过去几个世纪的降雨量变化进行每年确定的代理估计。通过补充现有的由热带珊瑚礁珊瑚和温带树木组成的代理数据网络，预计这些数据将直接有助于观测厄尔尼诺-南方涛动（ENSO）过去频率和强度的变化。热带是全球气候系统的重要组成部分，具有在季节到年际时间尺度上组织全球尺度气候异常的动力和能量。来自模式的证据表明，热带可能是全球气候变率在长时间尺度上的持续影响。热带气候的长期变化有可能影响到世界上整整四分之一人口的生活，主要是通过季节性正常降水和农业模式的中断。迄今为止，热带地区最重要的季节性到年度分辨率代用记录档案都来自于对珊瑚礁和冰芯的测量。然而，它们也有其局限性，因为很少有珊瑚记录早于现有的100-150年的历史观测记录和冰芯记录，而更古老的记录仅限于一些迅速消失的热带冰原。获得300-500年的重复记录的前景仍然具有挑战性，但同位素树木气候学在缩小数据差距方面提供了巨大的希望，并以这种方式为许多科学领域提供了广泛影响的潜力。

The scientific strategy for this research exploits recent breakthroughs in stable isotope dendro-ecology, mass spectrometry, and analytical chemistry to develop chronological and climate proxy data in tropical trees that lack rings. Tree-ring records have shown great potential for long term observations (500 years before present or longer) but are limited in extent because many tropical tree species form rings intermittently or not at all.The ultimate goal of this research is to develop annually resolved proxy estimates of rainfall variability from Indonesia for the past several centuries. These data are expected to directly contribute to observations of past changes in frequency and strength of the El Nino-Southern Oscillation (ENSO) by complementing the existing proxy data network composed of tropical reef corals and extratropical trees. The tropics are an important component of the global climate system, possessing the dynamics and energetics to organize global-scale climatic anomalies on seasonal to interannual time scales. Evidence from models suggests the tropics may be a persistent influence of global climate variability on long time scales. Long-term variability in the tropical climate has the potential to affect the lives of fully a quarter of the world's population primarily through the interruption of seasonally normal precipitation and agricultural patterns. To date the most important archives for seasonal to annual resolution proxy records in the tropics have been derived from measurements from coral reefs and ice cores. They have their limitations, however, as few coral records predate the existing 100-150 year long historical observational record and ice core records, while older, are limited to a few rapidly disappearing tropical ice fields. Prospects for obtaining replicated 300-500 year long records remain challenging but isotope dendroclimatology offers great promise in closing the data gap and, in this manner, offers the potential for broad impact to many scientific fields.