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Title: The Relative Warming Rates of Heat Events and Median Days in the Pacific Northwest from Observations and a Regional Climate Model
Abstract This paper examines the trends in hot summer days for the Pacific Northwest in observations and a regional climate model ensemble. Hot days are identified by the temperature threshold for several percentile values computed over 10-year intervals (85, 90, 95, and absolute maximum) to differentiate heat events of different intensities and are compared to the median temperature (50 th percentile). For the stations analyzed, the observed rate of warming during hot days is not statistically different from the warming rate of median days since the 1950s. However, for projections to 2100, hot days show a statistically significant increase in the warming rate of the hottest days compared to the warming rate for median days. Depending on location, the 95 th percentile daily maximum temperature shows a warming rate of up to 0.2°C per decade above the median warming rate. The divergence in the trends of median and extreme temperature shows substantial regional variation depending on local terrain and coastlines. The warming trend during hot days is related to the unique circulation patterns during heat events, which respond to different feedbacks and amplifying effects in the land-atmosphere system from those that prevail during typical days. The regional climate model simulations are taken from an ensemble of Weather Research and Forecasting (WRF) model simulations forced by 12 global climate model simulations from the 5 th Climate Model Intercomparison Project (CMIP5) using the RCP8.5 emissions scenario and 12-km grid spacing.  more » « less
Award ID(s):
2050928 2040626 2125646
Author(s) / Creator(s):
; ; ;
Date Published:
Journal Name:
Journal of Climate
Page Range / eLocation ID:
1 to 24
Medium: X
Sponsoring Org:
National Science Foundation
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