Lookup NU author(s): Doug Richardson,
Professor Hayley Fowler,
Professor Chris Kilsby
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2017 Royal Meteorological Society. Weather-pattern, or weather-type, classifications are a valuable tool in many applications as they characterize the broad-scale atmospheric circulation over a given region. This study analyses the aspects of regional UK precipitation and meteorological drought climatology with respect to a new set of objectively defined weather patterns. These new patterns are currently being used by the Met Office in several probabilistic forecasting applications driven by ensemble forecasting systems. Weather pattern definitions and daily occurrences are mapped to Lamb weather types (LWTs), and parallels between the two classifications are drawn. Daily precipitation distributions are associated with each weather pattern and LWT. Standardized precipitation index (SPI) and drought severity index (DSI) series are calculated for a range of aggregation periods and seasons. Monthly weather-pattern frequency anomalies are calculated for SPI wet and dry periods and for the 5% most intense DSI-based drought months. The new weather-pattern definitions and daily occurrences largely agree with their respective LWTs, allowing comparison between the two classifications. There is also broad agreement between weather pattern and LWT changes in frequencies. The new data set is shown to be adequate for precipitation-based analyses in the UK, although a smaller set of clustered weather patterns is not. Furthermore, intra-pattern precipitation variability is lower in the new classification compared to the LWTs, which is an advantage in this context. Six of the new weather patterns are associated with drought over the entire UK, with several other patterns linked to regional drought. It is demonstrated that the new data set of weather patterns offers a new opportunity for classification-based analyses in the UK.
Author(s): Richardson D, Fowler HJ, Kilsby CG, Neal R
Publication type: Article
Publication status: Published
Journal: International Journal of Climatology
Print publication date: 01/02/2018
Online publication date: 13/07/2017
Acceptance date: 08/06/2017
ISSN (print): 0899-8418
ISSN (electronic): 1097-0088
Publisher: John Wiley and Sons Ltd
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