Investigate the impact of climate change on daily extreme precipitation in the eastern U.S.
Abstract
Increase in heavy downpours have been observed across the U.S. An extreme index (the number of 2-day precipitation totals in a decade that exceeds a threshold corresponding to 5-year return period) has been shown to increase 30-70% in the eastern U.S. between the decades before 1960 and the 2001-2010 decade [Kunkel et al. 2013]. Intensity-Duration-Frequency (IDF) curve is a descriptive measure of extreme precipitation, and is commonly used to inform urban hydrological design. To understand how IDF curves are influenced by climate change is important for infrastructure planning and adaptation. As a first step towards this objective, this study investigates the potential changes in extreme precipitation at daily level over the eastern U.S. by a combination of statistical and dynamical downscaling approaches. The dynamical downscaling experiment is conducted with the Weather Forecast Model (Version 3.8), on the eastern U.S. domain and driven by a bias-corrected CMIP5 CESM dataset. The relationship between daily precipitation at coarse- and dynamically downscaled fine-grid levels are investigated using quantile-mapping and linear-regression methods with various calibration tweaks. The statistical relationship whose difference between future period and the historical baseline is comparable or smaller than the natural variability during 1950-2005 is then identified as not violating the stationarity assumption on the statistical relationship. The computationally cheaper identified statistical downscaling method is then used to downscale precipitation to station scale at National Weather Service Cooperative Observer Network locations on the domain. In a future study, the downscaled daily precipitation will be disaggregated to hourly level by the k-Nearest Neighbor method, and thus to facilitate construction of IDF curves. Kunkel et al. 2013 Monitoring and Understanding Trends in Extreme Storms: State of Knowledge
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMNH51B1934W
- Keywords:
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- 4303 Hydrological;
- NATURAL HAZARDSDE: 4313 Extreme events;
- NATURAL HAZARDSDE: 4321 Climate impact;
- NATURAL HAZARDSDE: 4333 Disaster risk analysis and assessment;
- NATURAL HAZARDS