On What Scale Can We Predict the Agronomic Onset of the West African Monsoon?
On What Scale Can We Predict the Agronomic Onset of the West African Monsoon?
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DOI：
10.1175/mwr-d-15-0274.1
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发表时间：
2016-04-01
影响因子：
3.2
通讯作者：
Parker, Douglas J.
中科院分区：
文献类型：
--
作者：
Fitzpatrick, Rory G. J.;Bain, Caroline L.;Parker, Douglas J.
对西非当地降雨开始的准确预测可以为当地利益攸关方和区域规划者提供重要信息。然而，与西非季风区域爆发的分析相比，局部季风爆发的空间变异性尚未得到广泛探讨。局地降水的空间噪声是局地降水预报分析缺乏的主要原因之一。提出了一种新的方法，用于评估整个西非地区局部发病连贯的空间尺度。这种新方法可以看作是类似于一个区域信号对局部噪声的起始分析。该方法突出显示局部发作表现出可量化的空间一致性程度的区域（表示局部发作区域或LORs）。研究发现，局部起跳表现出大量的空间一致性，LORs在整个研究区域都很明显；这与之前发现的结果相反。确定局部发生区域并了解其变异可以为季风可预测性的空间限制提供重要的见解。虽然在西非可以发现局部发病区，但其规模远远小于季节性降雨均匀性的规模。提出了一种潜在的利用局部发病区域的方法，表明每年热带锋面进展与当地农艺发病之间的联系。
Accurate prediction of the commencement of local rainfall over West Africa can provide vital information for local stakeholders and regional planners. However, in comparison with analysis of the regional onset of the West African monsoon, the spatial variability of the local monsoon onset has not been extensively explored. One of the main reasons behind the lack of local onset forecast analysis is the spatial noisiness of local rainfall. A new method that evaluates the spatial scale at which local onsets are coherent across West Africa is presented. This new method can be thought of as analogous to a regional signal against local noise analysis of onset. This method highlights regions where local onsets exhibit a quantifiable degree of spatial consistency (denoted local onset regions or LORs). It is found that local onsets exhibit a useful amount of spatial agreement, with LORs apparent across the entire studied domain; this is in contrast to previously found results. Identifying local onset regions and understanding their variability can provide important insight into the spatial limit of monsoon predictability. While local onset regions can be found over West Africa, their size is much smaller than the scale found for seasonal rainfall homogeneity. A potential use of local onset regions is presented that shows the link between the annual intertropical front progression and local agronomic onset.