P2C2: Northern and Southern Low-Latitude Precipitation Histories--Testing Ideas about Millennial and Orbital-Scale Climate Change

这个研究小组试图扩展北半球（东南亚）和南半球（南美洲）低纬度地区的洞穴方解石氧同位素组成的绝对年代记录。对于这些区域中的每一个，调查人员的目标是：(i)在时间上更深入地扩展记录；（二）扩大区域内的地理覆盖范围；（iii）提高关键时间范围内氧同位素分辨率；（iv）应用新开发的测年技术来完善和扩展年表。对于北部遗址，研究小组计划将记录延长到大约65万年前的另外三个冰期-间冰期旋回，并建立第四纪中期（130万至150万年前）的记录。对于南部地区，研究人员试图建立一个覆盖最后几个冰期-间冰期旋回的记录。有了这些新记录，主要研究人员将检验以下假设：(1)千年尺度气候变化的原因；(2)冰河时代终结的原因；(3)季风的长期变异机制；(4)季风降雨影响地区降雨氧同位素组成的控制因素。更好地了解低纬度地区降水的时空变异性对更广泛的科学界具有重要的科学价值。通过这个项目，研究人员将继续与中国和巴西科学家开展强有力的国际合作。该项目还支持一名博士后学者。

This research team seeks to extend absolute-dated records of the oxygen isotopic composition of speleothem calcite from the Northern Hemisphere (southeast Asia) and from Southern Hemisphere (South America) low latitude sites. For each of these regions, the investigators aim to: (i) extend the records deeper in time; (ii) broaden the geographic coverage within the region; (iii) increase the oxygen isotope resolution within key time ranges; and (iv) apply newly developed dating techniques to refine and extend chronologies. For the northern site, the team plans to extend the record an additional three glacial-interglacial cycles back to about 650,000 years ago and also establish a record in the mid-Quaternary (1.3 to 1.5 million years ago). For the southern site, the researchers seek to develop a record covering the last few glacial-interglacial cycles.With these new records, the principal investigators will test hypotheses related to: (1) the causes of millennial-scale climate change; (2) the causes of ice age terminations; (3) the mechanisms for long-term monsoon variability; and (4) the controls on the oxygen isotopic composition of rainfall in regions affected by monsoon rainfall.A better understanding of the temporal and spatial variability of precipitation over low latitude sites would be of great scientific value to the wider science community. Through this project, the researchers will continue to develop strong international collaborations with Chinese and Brazilian scientist. The project also supports a post-doctoral scholar.