Robustness of Meteorological Droughts in Dynamically Downscaled Climate Simulations

Journal Article · Tue Dec 08 00:00:00 EST 2015 · Journal of the American Water Resources Association

DOI:https://doi.org/10.1111/1752-1688.12374· OSTI ID:1401175

Ganguli, Poulomi ^[1]; Ganguly, Auroop R. ^[1]

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1. Sustainability and Data Sciences Laboratory Civil and Environmental Engineering Northeastern University 360 Huntington Avenue Boston Massachusetts 02115

Abstract We examine the robustness of a suite of regional climate models (RCMs) in simulating meteorological droughts and associated metrics in present‐day climate (1971‐2003) over the conterminous United States (U.S.). The RCMs that are part of North American Regional Climate Change Assessment Program (NARCCAP) simulations are compared with multiple observations over the climatologically homogeneous regions of the U.S. The seasonal precipitation, climatology, drought attributes, and trends have been assessed. The reanalysis‐based multi‐model median RCM reasonably simulates observed statistical attributes of drought and the regional detail due to topographic forcing. However, models fail to simulate significant drying trend over the Southwest and West. Further, reanalysis‐based NARCCAP runs underestimate the observed drought frequency overall, with the exception of the Southwest; whereas they underestimate persistence in the drought‐affected areas over the Southwest and West‐North Central regions. However, global climate model‐driven NARCCAP ensembles tend to overestimate regional drought frequencies. Models exhibit considerable uncertainties while reproducing meteorological drought statistics, as evidenced by a general lack of agreement in the Hurst exponent, which in turn controls drought persistence. Water resources managers need to be aware of the limitations of current climate models, while regional climate modelers may want to fine‐tune their parameters to address impact‐relevant metrics.

• Sponsoring Organization: USDOE
• OSTI ID: 1401175
• Journal Information: Journal of the American Water Resources Association, Journal Name: Journal of the American Water Resources Association Vol. 52 Journal Issue: 1; ISSN 1093-474X
• Publisher: Wiley-Blackwell
• Country of Publication: United States
• Language: English