Predicting the regional onset of the rainy season in West Africa
Predicting the regional onset of the rainy season in West Africa
复制标题
DOI：
10.1002/joc.1542
复制
发表时间：
2008-03-01
期刊：
影响因子：
--
通讯作者：
Bardossy, A.
中科院分区：
文献类型：
--
作者：
Laux, P.;Kunstmann, H.;Bardossy, A.
特别是在每年降水量仅限于几个月的地区，可靠确定雨季的开始和播种时间的开始对于可持续粮食生产至关重要。特别是自 20 世纪 80 年代中期以来，当地农民怀疑西非沃尔特盆地的发病日期越来越晚。为了调查这种猜测并开发可靠的工具来寻找最佳播种日期，我们通过多种统计技术分析了该地区雨季的到来。重点放在加纳和布基纳法索的沃尔特盆地地区。第一步，使用每日降水数据并另外考虑重要的植物生理方面，制定了两个基于模糊逻辑的爆发定义。在这种情况下，只有一个定义可能有助于判断目前的雨季是否已经开始。第二步，研究了预测当前季节开始日期的方法。在这种情况下，起始控制变量的检测起着重要作用。研究和评估了两种季风爆发日期预测策略：1) 通过空间模式主成分分析 (PCA) 和线性判别分析结合区域化天气降雨数据，以检测可靠的预测参数，并利用当前降雨数据对雨季、旱季和雨季爆发进行分类。2) 生成线性回归模型，利用区域的爆发日期来估计某些区域的雨季爆发，其中为了增强可预测性，在两种策略领域都应用了优化的定义参数化。版权所有 (c) 2007 英国皇家气象学会。
Particularly in regions, where precipitation is limited to a few months per year only, reliable determination of the onset of the rainy season and the start of the sowing time is of crucial importance to sustainable food production. Especially since the mid-1980s, an increasing delay of onset dates in the Volta basin of West Africa has been suspected by local farmers. To investigate this speculation and develop a reliable tool to find the optimal sowing date, the onset of the rainy season in the region was analysed by means of several statistical techniques. The focus was put on the region of the Volta basin in Ghana and Burkina Faso.In a first step, two fuzzy logic based definitions of the onset were developed using daily precipitation data and additionally accounting for important plant physiological aspects. In this context, only one definition is potentially useful to judge whether the current onset of the rainy season has already begun. In a second step, methods for predicting the onset date of the ongoing season were investigated. In this context, the detection of onset controlling variables plays a major role. Two strategies are investigated and evaluated for the prediction of the monsoon's onset dates:1) A combination of regionalized synoptic rainfall data by means of principal component analysis (PCA) in a spatial mode and linear discriminant analysis in order to detect reliable prediction parameters and allow for a classification of the rainy season, dry season, and the onset of the rainy season using current rainfall data.2) Linear regression models were generated to estimate the onset of the rainy season for certain regions using the onset dates of regions, where the onset has already begun.To enhance the predictability, optimized definition parameterisation in the field of both strategies was applied. Copyright (c) 2007 Royal Meteorological Society.