When Eastern India Oscillated Between Desert Versus Savannah‐Dominated Vegetation
When Eastern India Oscillated Between Desert Versus Savannah‐Dominated Vegetation
复制标题
DOI：
10.1029/2022gl099417
复制
发表时间：
2022-08
影响因子：
5.2
通讯作者：
Coralie Zorzi;S. Desprat;C. Clément;Kaustubh Thirumalaï;D. Oliviera;K. Anupama;S. Prasad;P. Martinez
中科院分区：
文献类型：
--
作者：
Coralie Zorzi;S. Desprat;C. Clément;Kaustubh Thirumalaï;D. Oliviera;K. Anupama;S. Prasad;P. Martinez
在末次冰期，热带水文循环在轨道和千年时间尺度上表现出很大的变化。然而，印度夏季风（ISM）的响应，其对陆地生态系统的相关影响，以及相关的强迫机制仍然存在争议。在这里，我们提出了花粉推断植被变化的海洋记录，表明印度东部在海洋同位素阶段3期间从木本稀树草原马赛克转变为末次冰期最大期期间由于大规模干燥而导致的草原。我们的数据表明，ISM最大值是在相位与地磁和岁差的最大值表明印度洋半球间的温度梯度冰川ISM变化的主导作用。持续和突然的旱地扩张的不同程度表明，在海因里希体育场事件和多巴火山爆发期间迅速规模的干旱开始。我们建议，ISM干旱事件的振幅发起高纬度和火山强迫，虽然岁差调制。
During the last glacial period, the tropical hydrological cycle exhibited large variability across orbital and millennial timescales. However, the response of the Indian summer monsoon (ISM), its related impact on terrestrial ecosystems, and associated forcing mechanisms remain controversial. Here we present a marine record of pollen‐inferred vegetation changes suggesting that eastern India shifted from woody‐savanna mosaics during Marine Isotopic Stage 3 to grasslands during the Last Glacial Maximum resulting from large‐scale drying. Our data shows that ISM maximum is in phase with obliquity and precession maxima suggesting a dominant role of the Indian Ocean interhemispheric temperature gradient on glacial ISM variability. Persistent and abrupt dryland expansions of varying magnitude suggest rapid‐scale onset of aridity during Heinrich Stadial events and during the Toba eruption. We propose that the amplitude of ISM drought events are initiated by high latitude and volcanic forcings, although modulated by precession.