Weather regimes and patterns associated with temperature-related excess mortality in the UK: a pathway to sub-seasonal risk forecasting

Wan Ting Katty Huang,Robert William Lee,Ting Sun,Andrew Charlton-Perez,Christophe Sarran,Robert Neal

doi:10.1088/1748-9326/abcbba

Abstract

Non-optimal temperatures, both warm and cold, are associated with enhanced mortality in the United Kingdom (UK). In this study we demonstrate a pathway to sub-seasonal and medium range forecasting of temperature-related mortality risk by quantifying the impact of large-scale weather regimes and synoptic scale weather patterns on temperature-associated excess deaths in 12 regions across the UK. We find a clear dominance of the NAO− regime in leading to high wintertime excess mortality across all regions. In summer, we note that cold spells lead to comparable cumulative excess mortality as moderate hot days, with cold days accounting for 11 (London) to 100% (Northern Ireland) of the summer days with the highest 5% cumulative excess mortality. However, exposure to high temperatures is typically associated with an immediate but short lived spike in mortality, while the impact of cold weather tends to be more delayed and spread out over a longer period. Weather patterns with a Scandinavian high component are most likely to be associated with summer hot extremes, while a strong zonal jet stream weather pattern which rarely occurs in summer is most likely to be associated with summer cold spells.

Highlights

Excess mortality associated with extreme hot and cold temperatures represents a significant public health risk and is a topic well studied in the public health literature (e.g. Analitis et al 2008, Basu 2009, Gasparrini et al 2015, Hajat et al 2016, Ryti et al 2016)
Hot days are commonly associated with a slight decrease in mortality after the initial peak as the heat exposure led to the death of people who would otherwise have died a few days later
The peak in relative risk (RR) associated with a single cold day occurs around 2 d after the initial exposure, which can be attributed to heart attacks resulting from increased blood viscosity (Keatinge 2002)

Summary

Introduction

Excess mortality associated with extreme hot and cold temperatures represents a significant public health risk and is a topic well studied in the public health literature (e.g. Analitis et al 2008, Basu 2009, Gasparrini et al 2015, Hajat et al 2016, Ryti et al 2016). While the physiological effects differ, the main causes of mortality associated with both temperature extremes are related to increased occurrence of deadly heart attacks, strokes, and respiratory diseases (Keatinge 2002, Analitis et al 2008, Arbuthnott and Hajat 2017, Song et al 2017). Previous studies have mainly focused on the direct relationship between mortality and temperature (e.g. Hajat et al 2014, Gasparrini et al 2015), while fewer have noted synoptic weather patterns associated with enhanced excess mortality in different parts of the world (e.g. Kassomenos et al 2007, Pena et al 2015). An advantage of linking mortality to large scale weather patterns is the increased persistence, predictability, and forecast skill horizon with increasing spatial scales in the atmosphere

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Conclusion