Interhemispheric dynamics of the African rainbelt during the late Quaternary
Interhemispheric dynamics of the African rainbelt during the late Quaternary
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DOI：
10.1016/j.quascirev.2015.06.021
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发表时间：
2015-09
影响因子：
4
通讯作者：
J. Singarayer;S. Burrough
中科院分区：
文献类型：
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作者：
J. Singarayer;S. Burrough
第四纪晚期非洲热带和亚热带地区降水变化的空间格局一直存在争议。流行的假说有不同的推论：（1）半球间湿相的不对称性是由太阳辐射控制的;（2）热带雨带的对称收缩和扩张;（3）南部非洲通过印度洋的海面温度对可用水分的独立控制。在这项研究中，我们使用气候模型模拟覆盖末次冰期（120 kyr）与HadCM 3和PMIP 3（古气候模型相互比较项目）的多模型合奏，以调查非洲雨带的长期行为，并测试这些模拟对现有的经验古水文记录。通过区域模型数据的比较，我们发现的几个假设的有效性的证据，与各种拟议的过程同时发生，但不同的区域重点（例如，在季节性的极端和对称的扩张/收缩向西赤道地区的不对称转变）。至关重要的是，降雨量的变化与多种强迫机制有关，这些机制在冰川周期的空间和时间上都有所不同;在解释和推断通常相对较短的古环境记录时，这是一个重要的考虑因素。
The spatial pattern of precipitation variability in tropical and subtropical Africa over the late Quaternary has long been debated. Prevailing hypotheses variously infer (1) insolation-controlled asymmetry of wet phases between hemispheres, (2) symmetric contraction and expansion of the tropical rainbelt, and (3) independent control on moisture available in Southern Africa via sea surface temperatures in the Indian Ocean. In this study we use climate-model simulations covering the last glacial cycle (120 kyr) with HadCM3 and the multi-model ensembles from PMIP3 (the Palaeoclimate Model Intercomparison Project) to investigate the long-term behaviour of the African rainbelt, and test these simulations against existing empirical palaeohydrological records. Through regional model-data comparisons we find evidence for the validity of several hypotheses, with various proposed processes occurring concurrently but with different regional emphasis (e.g. asymmetric shifts at the seasonal extremes and symmetric expansions/contractions towards West equatorial regions). Crucially, variations in rainfall are associated with multiple forcing mechanisms that vary in their dominance both spatially and temporally over the glacial cycle; an important consideration when interpreting and extrapolating from often relatively short palaeoenvironmental records.