ONSET OF SAHELIAN DROUGHT VIEWED AS A FLUCTUATION-INDUCED TRANSITION
ONSET OF SAHELIAN DROUGHT VIEWED AS A FLUCTUATION-INDUCED TRANSITION
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DOI：
10.1002/qj.49711649110
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发表时间：
1990-01-01
影响因子：
8.9
通讯作者：
NICOLIS, C
中科院分区：
文献类型：
--
作者：
DEMAREE, GR;NICOLIS, C
对西萨赫勒地区有代表性的降水数据集进行了统计分析，发现了60年代末的跃变。有人认为，与该记录相关的主要特征可以用波动引起的两种稳定降水状态之间的过渡来解释：“湿润”和“干燥”状态。构造了一个包含优势非线性的最小模型，并根据数据确定了模型参数。通过从平均值和较高的停留时间矩推导出的两种稳定状态的相对稳定性，试图得出交替状态持续时间的统计预测。模型预测的行为在定性上与实际记录一致。
A statistical analysis of representative sets of rainfall data in the west Sahel region is performed and a jump transition in the late sixties is detected. It is suggested that the main features associated with the record can be accounted for by a fluctuation‐induced transition between two stable precipitation regimes: a ‘humid’ and a ‘dry’ state. A minimal model involving the dominant nonlinearities is constructed and its parameters determined from the data. an attempt is made to arrive at a statistical prediction of the duration of the alternate regimes through the relative stability of the two stable states as deduced from mean values and higher moments of residence times. the behaviour predicted by the model is in good qualitative agreement with the record.