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

该研究小组试图扩大北半球(东南亚)和南半球(南美洲)低纬度地区洞穴状方解石的氧同位素组成的绝对年代记录。对于每个区域，调查人员的目标是：(1)在时间上更深入地扩展记录；(2)扩大区域内的地理覆盖范围；(3)提高关键时间范围内的氧同位素分辨率；(4)应用新开发的测年技术来完善和延长年表。对于北部遗址，该团队计划将记录延长到大约65万年前的另外三个冰川-间冰期周期，并在第四纪中期(130万至150万年前)创造记录。对于南部的站点，研究人员试图建立一个涵盖最近几个冰川-间冰期周期的记录。通过这些新的记录，主要研究人员将检验与以下假设有关的假设：(1)千年尺度气候变化的原因；(2)冰期终止的原因；(3)长期季风变化的机制；(4)对受季风雨影响的地区降雨的氧同位素组成的控制。更好地了解低纬度站点降水的时空变化将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.