Assessing the Skill of Hydrology Models at Simulating the Water Cycle in the HJ Andrews LTER: Assumptions, Strengths and Weaknesses

NOTE: Please note the last two co-authors on this talk. The automated system would not allow me to add additional co-authors after the seventh (7th) co-author, Alex Abdelnour. Information about the 8th and 9th co-authors can be found, below (and in the "notes" section). After their relevant information is included, please remove this note and the "Authors" and "Affiliations/Info" sections, below, from the abstract. Thank you.

Authors:

Jeremiah Osborne-Gowey¹, Dominique Bachelet^2,3, Alan Hamlet⁴, Elizabeth Garcia⁵, Christina Tague⁵, Robert McKane⁶, Alex Abdelnour⁷, Marc Stieglitz⁷, Feifei Pan⁸

Affiliations/Contact Info:

1. Conservation Biology Institute, 136 SW Washington Ave., Suite 202, Corvallis, OR 97333.
2. Conservation Biology Institute, Olympia, WA.
3. Oregon State University, Department of Biological and Ecological Engineering, Corvallis, OR.
4. University of Washington, Civil and Environmental Engineering, Seattle, WA.
5. University of California, Donald Bren School of Environmental Science and Management, Santa Barbara, CA.
6. US Environmental Protection Agency, Western Ecology Division, Corvallis, OR.
7. Associate Professor, School of Civil and Environmental Engineering, Georgia Institute of Technology, 790 Atlantic Drive
   Atlanta, GA 30332-0355. 404-385-6530. marcstieglitz@gmail.com.
8. Assistant Professor, Department of Geography, University of North Texas, EESAT Building, Room325K, Denton, TX 76203. 940-369-5109, Feifei.Pan@unt.edu.

Simulated impacts of climate on hydrology can vary greatly as a function of the scale of the input data, model assumptions, and model structure. Four models are commonly used to simulate streamflow in the Pacific Northwest US: the MC1 Dynamic Global Vegetation Model which was originally designed to simulate ecosystem processes at the regional to global scale, the Variable Infiltration Capacity (VIC) model based on the physical representation of the hydrology cycle and used for regional assessments, the Regional Hydro-Ecologic Simulation System (RHESSys) model which was designed to address watershed scale coupling between hydrology and vegetation carbon and nitrogen cycling, and the Visualizing Ecosystems for Land Management Assessments (VELMA) model which was designed to address integrated responses of vegetation, soil, and water resources. We conducted a comparison ofthe four models  based on streamflow and other observed long-term data from the HJ Andrews Long Term Ecological Research site.  Our objective was to better understand differences in the models’ representation of water dynamics at the watershed scale. We 1) document each model’s needs (soil and climate inputs, initial conditions, spinup protocols), 2) compare the readily available model results with H.J. Andrews observations, and 3) report on model strengths and weaknesses (at what scale are the models most relevant? Can models inform each other?).