Western US high June 2015 temperatures and their relation to global warming and soil moisture

Journal article

Abstract TheWestern US statesWashington (WA), Oregon (OR) and California (CA) experienced extremely high temperatures in June 2015. The temperature anomalies were so extreme that they cannot be explained with global warming alone. We investigate the hypothesis that soil moisture played an important role as well. We use a land surface model and a large ensemble from the weather@home modelling effort to investigate the coupling between soil moisture and temperature in a warming world. Both models show that May was anomalously dry, satisfying a prerequisite for the extreme heat wave, and they indicate that WA and OR are in a wet-to-dry transitional soil moisture regime. We use two different land surface-atmosphere coupling metrics to show that there was strong coupling between temperature, latent heat and the effect of soil moisture deficits on the energy balance in June 2015 in WA and OR. June temperature anomalies conditioned on wet/dry conditions show that both the mean and extreme temperatures become hotter for dry soils, especially in WA and OR.

Authors: Philip, S; Kew, S; Hauser, M; Guillod, B; Teuling, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer Verlag
• Journal: Climate Dynamics
• Volume: 50
• Issue: 7-8
• Pages: 2587-2601
• Publication date: 2017-06-17
• Acceptance date: 2017-06-09
• DOI: 10.1007/s00382-017-3759-x
• EISSN: 1432-0894
• ISSN: 0930-7575