The probability of the impact of ENSO on precipitation and near-surface temperature
The probability of the impact of ENSO on precipitation and near-surface temperature
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DOI：
10.1016/j.crm.2013.12.002
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发表时间：
2014-01-01
影响因子：
4.4
通讯作者：
Ineson, S.
中科院分区：
文献类型：
--
作者：
Davey, M. K.;Brookshaw, A.;Ineson, S.
厄尔尼诺-南方涛动（ENSO）事件对区域气候的广泛影响是众所周知的，此类事件可产生相当大的社会经济影响。因此，在预测或正在进行的ENSO条件下，具有实际重要性的一个方面是各种气候类别发生的机会。利用降水和近地表温度的观测和再分析数据集，系统地分析了这方面的三个近等概率类别（低于正常、接近正常、高于正常），以量化赤道中东部太平洋海面温度异常时（如厄尔尼诺和拉尼娜事件期间）它们发生的概率，重点是陆地面积和季节性（三个月平均值）值。通过使用最近可用的网格数据集，本分析补充和更新了以前对ENSO影响的分析。通过对全球数据集的逐点分析，得到了以ENSO状态为条件的各类事件发生率的空间图。与以前的分析一致，在热带和温带地区，确定了几个速率远高于偶然预期的区域。区域平均值被用来更详细地考察其中的一些因素，特别是描述ENSO影响的强烈季节性依赖关系。这取决于ENSO的季节性、遥相关路径和当地气候之间的相互作用：事实上，在一些地方，相反的影响在一年的不同时间出现。该方法基于从历史记录中计算出的列联表，并有效地量化了在特定季节和地点出现高于正常水平的降雨的可能性，例如，这取决于赤道太平洋海面温度的状态。发生率为风险评估和管理提供了比诸如相关性或组合等统计数据更直接的相关信息。每个ENSO事件都是不同的，并与其他气候因素一起发生，因此，尽管历史速率提供了一般指导，但它们不应被视为对某个即将发生或正在发生的ENSO事件影响的预测。爱思唯尔B.V.版权所有
The widespread influence of El Nino Southern Oscillation (ENSO) events on regional climate is well known, and such events can have considerable socio-economic impact. Thus an aspect of practical importance is the chance of the occurrence of various climate categories given that ENSO conditions are predicted or underway. Using observational and re-analysis datasets for precipitation and near-surface temperature this aspect is analysed systematically in terms of three near-equiprobable categories (below normal, near normal, above normal) to quantify the probability of their occurrence when central-east equatorial Pacific sea surface temperatures are abnormal, as during El Nino and La Nina events, with emphasis on land areas and on seasonal (three-month average) values. By using recently available gridded datasets, this analysis complements and updates previous analyses of ENSO impact. Spatial maps of the rate of occurrence of various categories conditional on ENSO state are obtained by point-by-point analysis of the global datasets. Consistent with previous analyses, several regions with rates well above those expected by chance are identified, in both tropical and extratropical sectors. Regional averages are used to examine a selection of these in more detail, in particular to describe the strong seasonal dependencies of ENSO influences. These depend on the interplay between the seasonality of ENSO, of teleconnection pathways and of local climate: indeed in several locations opposite effects arise at different times of year.The methodology is based on contingency tables calculated from historical records, and effectively quantifies the probability that, for example, above-normal rainfall will occur in a given season and location conditional on the state of equatorial Pacific sea surface temperature. The rates of occurrence provide more directly relevant information for risk assessment and management than do statistics such as correlations or composites. Each ENSO event is different and occurs in conjunction with other climatic factors, so while the historical rates provide general guidance they should not be regarded as a prediction of impacts for a particular imminent or ongoing ENSO event. Crown Copyright (C) 2014 Published by Elsevier B.V.