Regional-Scale Rainy Season Onset Detection: A New Approach Based on Multivariate Analysis
Regional-Scale Rainy Season Onset Detection: A New Approach Based on Multivariate Analysis
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DOI：
10.1175/jcli-d-12-00730.1
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发表时间：
2013-11-01
影响因子：
4.9
通讯作者：
Moron, Vincent
中科院分区：
文献类型：
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作者：
Boyard-Micheau, Joseph;Camberlin, Pierre;Moron, Vincent
在农业气候学中，雨季开始和结束的日期通常是根据几个经验降雨阈值的组合来确定的。例如，开始可以是连续N天中的第一个潮湿的日子，接收至少P毫米，而没有持续n天的干旱期，并且在接下来的C天中接收小于p毫米。这些阈值是根据经验确定的参数，以符合特定作物的要求，并考虑到当地的气候条件。这种地方尺度的农业气候定义是严格的，因为每一个阈值不一定可以转换到其他作物和其他气候环境。一种新的方法来定义发病/停止日期和监测其年际变化在区域尺度。这种新方法对参数化和局部规模的突发事件不太敏感，但在局部规模仍有一定的意义。该方法在主成分分析中考虑了降雨阈值的多种组合，从而提取出跨空间和参数的鲁棒信号。区域尺度的开始/停止日期是不平等的影响输入降雨参数用于定义当地的雨季开始。看来，P是一个关键的参数来定义发病，C起着重要的作用，在大多数站，N似乎是边际影响。
In agroclimatology, the rainy season onset and cessation dates are often defined from a combination of several empirical rainfall thresholds. For example, the onset may be the first wet day of N consecutive days receiving at least P millimeters without a dry spell lasting n days and receiving less than p millimeters in the following C days. These thresholds are parameterized empirically in order to fit the requirements of a given crop and to account for local-scale climatic conditions. Such local-scale agroclimatic definition is rigid because each threshold may not be necessarily transposable to other crops and other climate environments. A new approach is developed to define onset/cessation dates and monitor their interannual variability at the regional scale. This new approach is less sensitive to parameterization and local-scale contingencies but still has some significance at the local scale. The approach considers multiple combinations of rainfall thresholds in a principal component analysis so that a robust signal across space and parameters is extracted. The regional-scale onset/cessation date is unequally influenced by input rainfall parameters used for the definition of the local rainy season onset. It appears that P is a crucial parameter to define onset, C plays a significant role at most stations, and N seems to be of marginal influence.