Large ensemble simulations of worst heatwaves with importance sampling

Large ensemble simulations of worst heatwaves with importance sampling

Challenge: How to simulate 100 millennial heatwaves at the cost of 100 simulations?

Nudging a stochastic weather generator based on atmospheric circulation analogs towards high local temperatures [here temperature average between Madrid, Toulouse, Orly, De Bilt and Berlin], to obtain the warmest summers that could be, starting on a June 1st and the armest summers that could be, with a weather patterns that are similar to observations. This is a proof of concept of a methodology to simulate unprecedented events, by resampling observations. We performed application to simulate a worst case scenario (warm December then wet spring) leading to low crop yield.

References:

[1] Yiou, P. and Jézéquel, A.:, Geosci. Model Dev., 13, 763–781, https://doi.org/10.5194/gmd-13-763-2020, 2020.

[2] Pfleiderer, P., Jézéquel, A., Legrand, J., Legrix, N., Markantonis, I., Vignotto, E., and Yiou, P.: Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2020-32, 2020.

Authors:

YIOU Pascal (LSCE-IPSL, CNRS), JEZEQUEL Aglaé

Temperatures of the warmest summers that could be, starting on a June 1st (red) and temperature of the the warmest summers that could be, with a weather patterns that are similar to observations (blue)