Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1007/s00382-017-3621-1 |
Interannual rainfall variability and SOM-based circulation classification | |
Wolski, Piotr; Jack, Christopher; Tadross, Mark; van Aardenne, Lisa; Lennard, Christopher | |
2018 | |
发表期刊 | CLIMATE DYNAMICS
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ISSN | 0930-7575 |
EISSN | 1432-0894 |
出版年 | 2018 |
卷号 | 50页码:479-492 |
文章类型 | Article |
语种 | 英语 |
国家 | South Africa |
英文摘要 | Self-Organizing Maps (SOM) based classifications of synoptic circulation patterns are increasingly being used to interpret large-scale drivers of local climate variability, and as part of statistical downscaling methodologies. These applications rely on a basic premise of synoptic climatology, i.e. that local weather is conditioned by the large-scale circulation. While it is clear that this relationship holds in principle, the implications of its implementation through SOM-based classification, particularly at interannual and longer time scales, are not well recognized. Here we use a SOM to understand the interannual synoptic drivers of climate variability at two locations in the winter and summer rainfall regimes of South Africa. We quantify the portion of variance in seasonal rainfall totals that is explained by year to year differences in the synoptic circulation, as schematized by a SOM. We furthermore test how different spatial domain sizes and synoptic variables affect the ability of the SOM to capture the dominant synoptic drivers of interannual rainfall variability. Additionally, we identify systematic synoptic forcing that is not captured by the SOM classification. The results indicate that the frequency of synoptic states, as schematized by a relatively disaggregated SOM (7 x 9) of prognostic atmospheric variables, including specific humidity, air temperature and geostrophic winds, captures only 20-45% of interannual local rainfall variability, and that the residual variance contains a strong systematic component. Utilising a multivariate linear regression framework demonstrates that this residual variance can largely be explained using synoptic variables over a particular location; even though they are used in the development of the SOM their influence, however, diminishes with the size of the SOM spatial domain. The influence of the SOM domain size, the choice of SOM atmospheric variables and grid-point explanatory variables on the levels of explained variance, is consistent with the general understanding of the dominant processes and atmospheric variables that affect rainfall variability at a particular location. |
英文关键词 | SOM Synoptic circulation Rainfall variability Southern Africa |
领域 | 气候变化 |
收录类别 | SCI-E |
WOS记录号 | WOS:000422908700030 |
WOS关键词 | SELF-ORGANIZING MAPS ; SOUTH-AFRICA ; PRECIPITATION |
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/35857 |
专题 | 气候变化 |
作者单位 | Univ Cape Town, Climate Syst Anal Grp, Cape Town, South Africa |
推荐引用方式 GB/T 7714 | Wolski, Piotr,Jack, Christopher,Tadross, Mark,et al. Interannual rainfall variability and SOM-based circulation classification[J]. CLIMATE DYNAMICS,2018,50:479-492. |
APA | Wolski, Piotr,Jack, Christopher,Tadross, Mark,van Aardenne, Lisa,&Lennard, Christopher.(2018).Interannual rainfall variability and SOM-based circulation classification.CLIMATE DYNAMICS,50,479-492. |
MLA | Wolski, Piotr,et al."Interannual rainfall variability and SOM-based circulation classification".CLIMATE DYNAMICS 50(2018):479-492. |
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