Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1002/joc.6260 |
Direct and indirect seasonal rainfall forecasts for East Africa using global dynamical models | |
Colman, Andrew W.1; Graham, Richard J.1; Davey, Michael K.2 | |
2019-08-26 | |
发表期刊 | INTERNATIONAL JOURNAL OF CLIMATOLOGY
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ISSN | 0899-8418 |
EISSN | 1097-0088 |
出版年 | 2019 |
文章类型 | Article;Early Access |
语种 | 英语 |
国家 | England |
英文摘要 | Regional-scale seasonal climate outlooks are typically produced using forecast information either local to the region or from another area with teleconnections to the region. Dynamical global long-range forecast (LRF) systems can provide both types of information, and these two approaches are compared in the context of seasonal rainfall forecasts for two adjoining areas in the Greater Horn of Africa region in tropical East Africa. The direct method utilizes the unprocessed LRF outputs for the region. For the "indirect" method, canonical correlation analysis is used and works by identifying patterns in historical LRF predictions over large tropical domains that relate to observed variability in the East Africa regions. For a given year, projections of the LRF forecasts onto those patterns can then be employed to construct the regional forecasts. This approach takes advantage of the tendency for LRF systems to have greater skill for large-scale variability than for smaller regional-scale features. Using case studies, it is found the two approaches contain complementary information: the indirect approach can provide notable skill benefits in years with strong large-scale forcing while in some years, particularly when large-scale signals are weak, the "direct" forecast are superior. Skill comparisons over many years found that, although results are region/season dependent, in general the indirect approach has higher skill overall-with improvements equal to or greater than those afforded by a 1-month reduction in lead time with the direct approach. Results for both methods used separately and in combination are provided for the March-April-May and September-to-December seasons in the two regions, using data from currently operational dynamical LRF systems. Skill was best for the September-to-December season in the southern region, using "indirect" forecasts. The "direct" approach was better than "indirect" for the March-to-May season in the northern region. In general, combination did not produce a substantial benefit. |
英文关键词 | canonical correlation analysis dynamical long-range forecast systems Greater Horn of Africa seasonal rainfall prediction |
领域 | 气候变化 |
收录类别 | SCI-E |
WOS记录号 | WOS:000483431500001 |
WOS关键词 | CANONICAL CORRELATION ; SURFACE-TEMPERATURE ; GREATER HORN ; PREDICTION ; PREDICTABILITY ; PRECIPITATION ; VARIABILITY ; SKILL |
WOS类目 | Meteorology & Atmospheric Sciences |
WOS研究方向 | Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/186129 |
专题 | 气候变化 |
作者单位 | 1.Met Off, Exeter, Devon, England; 2.Univ Cambridge, Dept Appl Math, Cambridge, England |
推荐引用方式 GB/T 7714 | Colman, Andrew W.,Graham, Richard J.,Davey, Michael K.. Direct and indirect seasonal rainfall forecasts for East Africa using global dynamical models[J]. INTERNATIONAL JOURNAL OF CLIMATOLOGY,2019. |
APA | Colman, Andrew W.,Graham, Richard J.,&Davey, Michael K..(2019).Direct and indirect seasonal rainfall forecasts for East Africa using global dynamical models.INTERNATIONAL JOURNAL OF CLIMATOLOGY. |
MLA | Colman, Andrew W.,et al."Direct and indirect seasonal rainfall forecasts for East Africa using global dynamical models".INTERNATIONAL JOURNAL OF CLIMATOLOGY (2019). |
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