Extreme high daily maximum temperature in the USA by the 2050 and 2100 horizons

Electricity generation assets need to withstand climatological hazards all along their operating period. With the ongoing climate change, high temperature extremes are expected to increase, therefore, climate change needs to be accounted for in the estimations of extreme temperature levels at the design stage.

This study showcases a methodology designed to compute maps of daily maximum temperature return levels in summer over the continental USA by 2050 and the end of the century. The methodology first consists in building a variable whose extremes can be considered as stationary in order to then apply the statistical Extreme Value Theory to compute return levels. Previous studies (Parey et al., 2013) had shown that once the trends in mean and standard deviation are removed, the extremes of the reduced variable can be considered as stationary. The reduced variable is thus computed for daily maximum temperatures at each grid point across the continental USA in summer using the ERA5 reanalysis over the 1950-2014 period. Then, once the desired return level is estimated for this variable, temperature levels are obtained by re-introducing the removed information about the mean and the standard deviation of summer temperature at the desired horizon (Parey et al., 2013). To do so, a set of 9 CMIP6 climate models with 3 emission scenarios, SSP1-2.6, SSP2-4.5 and SSP3-7.0, is considered. For each time horizon, 27 extreme summer temperature maps are produced. Then, a criterium is designed to sum up the information and decide whether two different maps give significantly different results. Finally, once the criterium is applied to each pair of maps, either scenario by scenario or all scenarios together, a classification is applied to identify groups of statistically different maps.

 

 

References:

Parey S., Hoang TTH, Dacunha-Castelle D.: The importance of mean and variance in predicting changes in temperature extremes, Journal of Geophysical Research: Atmospheres, Vol 118, 1-12, 2013, doi:10.1002/jgrd.50629

Parey S., Hoang T.T.H., Dacunha-Castelle D.: Future high temperature extremes and stationarity, Natural Hazards, 2019, https://doi.org/10.1007/s11069-018-3499-1