Future Heat Waves over Paris Metropolitan Area

Abstract

The aim of this study is to analyse urban heat wave events in present climate (1961-1990) and their evolution in a changing future climate (2021-2050, 2071-2100). We used daily observations of temperature from stations in Paris, climate model projections following three SRES scenarios (A2, A1B, B1) and issued from several regional climate models. A heat wave is detected within observed or simulated time-series by a peak, when temperatures exceed the 99.9th percentile. Its duration is determined by all adjacent days to this peak. Events are extracted, then validated within observations and 12 climatic simulations. Over 2071-2100, we count 3.5, 3.8 and 2.1 events per year for A2, A1B and B1 scenario respectively, using one climate model. The ten A1B climate models simulate 1.5 heat waves per year on average. Despite a large variability, HW characteristics show an overall trend to an increase in duration and intensity, which is more pronounced at night-time. Over 2071-2100, extreme events have night-time temperatures of 28°C for A1B (against 20°C in the 2003 heat wave); day-time temperatures of 45°C for A1B (against 39°C in 2003) and last up to 1 month. © Springer Science+Business Media B.V. 2012.