Title: How do modeling decisions affect the spread among hydrologic climate change projections? Exploring a large ensemble of simulations across a diversity of hydroclimates

Abstract

Methodological choices can have strong effects on projections of climate change impacts on hydrology. In this study, we investigate the ways in which four different steps in the modeling chain influence the spread in projected changes of different aspects of hydrology. To form the basis of these analyses, we constructed an ensemble of 160 simulations from permutations of two Representative Concentration Pathways, 10 global climate models, two downscaling methods, and four hydrologic model implementations. The study is situated in the Pacific Northwest of North America, which has relevance to a diverse, multinational cast of stakeholders. We analyze the effects of each modeling decision on changes in gridded hydrologic variables of snow water equivalent and runoff, as well as streamflow at point locations. Results show that the choice of representative concentration pathway or global climate model is the driving contributor to the spread in annual streamflow volume and timing. On the other hand, hydrologic model implementation explains most of the spread in changes in low flows. Finally, by grouping the results by climate region the results have the potential to be generalized beyond the Pacific Northwest. Future hydrologic impact assessments can use these results to better tailor their modeling efforts.

Authors:

Chegwidden, Oriana S.  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-1376-3835"

Nijssen, Bart  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-4062-0322"

Rupp, David E.  ^[2];

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• Search DOE PAGES for ORCID "0000-0003-3562-2072"

Arnold, Jeffrey R. ^[3]; Clark, Martyn P.  ^[4];

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• Search DOE PAGES for ORCID "0000-0002-2186-2625"

Hamman, Joseph J.  ^[5];

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• Search DOE PAGES for ORCID "0000-0001-7479-8439"

Kao, Shih‐Chieh  ^[6];

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• Search DOE PAGES for ORCID "0000-0002-3207-5328"

Mao, Yixin  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-2080-5741"

Mizukami, Naoki ^[5]; Mote, Philip ^[2]; Pan, Ming  ^[7];

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• Search DOE PAGES for ORCID "0000-0003-3350-8719"

Pytlak, Erik ^[8]; Xiao, Mu  ^[9]

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• Search DOE PAGES for ORCID "0000-0002-7437-0739"

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+ Show Author Affiliations

1. Univ. of Washington, Seattle, WA (United States)
2. Oregon State Univ., Corvallis, OR (United States)
3. United States Army Corps of Engineers, Climate Preparedness and Resilience Program, Seattle, WA (United States)
4. National Center for Atmospheric Research, Boulder, CO (United States); University of Saskatchewan, Canmore, Alberta (Canada)
5. National Center for Atmospheric Research, Boulder, CO (United States)
6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
7. Princeton Univ., NJ (United States)
8. Bonneville Power Administration, Portland, OR (United States)
9. Univ. of California, Los Angeles, CA (United States)

Publication Date:

Tue Apr 30 00:00:00 EDT 2019

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE)

OSTI Identifier:

1528698

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

Earth's Future

Additional Journal Information:

Journal Volume: 7; Journal ID: ISSN 2328-4277

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

58 GEOSCIENCES; hydrologic ensemble spread; climate impacts; hydroclimatology; Pacific Northwest