Response of Extreme Precipitations to Changes in Surface and Dew-Point Temperatures

**Présentation en anglais**

Extreme precipitation events are expected to increase in frequency and intensity in the future climate, but the magnitude of these changes remains uncertain.

The relationship between extreme precipitation and the surface temperature has been investigated to more robustly assess projected increases in extreme precipitation considering that projected temperature is more adequately simulated.

Relationships between extreme precipitation (daily and sub-daily) and surface air temperature (SAT) or surface dew-point temperature (SDPT) was analyzed using the 50-member ensemble from the fifth version of the Canadian Regional Climate Model covering Northeastern North America over the period 1956–2099.

Temperature-precipitation scaling rates (TPSRs) were estimated using local SAT and SDPT seasonal anomalies as covariate over both periods for 2- to 100-year extreme precipitation and durations ranging from 1 to 24 h. Contrasting responses were obtained when using SAT or SDPT, especially in the southern part of the domain.

Median scaling rates over the entire domain for SDPT were close to the Clausius-Clapeyron (C-C) scaling (≈7% /°C) while they were much smaller for SAT and even negative in southern regions, showing that moisture availability is a key factor for these regions.

TPSR based on SDPT is also more robustly constrained and can be used to estimate changes in short-duration extreme precipitation in a future period from TPSR in the historical period over a large part of the domain.