Scalability of grid- and subbasin-based land surface modeling approaches for hydrologic simulations

Journal Article · Thu Mar 27 00:00:00 EDT 2014 · Journal of Geophysical Research: Atmospheres

DOI:https://doi.org/10.1002/2013JD020493· OSTI ID:1129354

Tesfa, Teklu K. ^[1]; Ruby Leung, L. ^[1]; Huang, Maoyi ^[1]; Li, Hong-Yi ^[1]; Voisin, Nathalie ^[1]; Wigmosta, Mark S. ^[1]

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1. Pacific Northwest National Laboratory, Richland Washington USA

This paper investigates the relative merits of grid- and subbasin-based land surface modeling approaches for hydrologic simulations, with a focus on their scalability (i.e., abilities to perform consistently across a range of spatial resolutions) in simulating runoff generation. Simulations produced by the grid- and subbasin-based configurations of the Community Land Model (CLM) are compared at four spatial resolutions (0.125o, 0.25o, 0.5o and 1o) over the topographically diverse region of the U.S. Pacific Northwest. Using the 0.125o resolution simulation as the “reference”, statistical skill metrics are calculated and compared across simulations at 0.25o, 0.5o and 1o spatial resolutions of each modeling approach at basin and topographic region levels. Results suggest significant scalability advantage for the subbasin-based approach compared to the grid-based approach for runoff generation. Basin level annual average relative errors of surface runoff at 0.25o, 0.5o, and 1o compared to 0.125o are 3%, 4%, and 6% for the subbasin-based configuration and 4%, 7%, and 11% for the grid-based configuration, respectively. The scalability advantages of the subbasin-based approach are more pronounced during winter/spring and over mountainous regions. The source of runoff scalability is found to be related to the scalability of major meteorological and land surface parameters of runoff generation. More specifically, the subbasin-based approach is more consistent across spatial scales than the grid-based approach in snowfall/rainfall partitioning, which is related to air temperature and surface elevation. Scalability of a topographic parameter used in the runoff parameterization also contributes to improved scalability of the rain driven saturated surface runoff component, particularly during winter. Hence this study demonstrates the importance of spatial structure for multi-scale modeling of hydrological processes, with implications to surface heat fluxes in coupled land-atmosphere modeling.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1129354
• Report Number(s): PNNL-SA-96701
• Journal Information: Journal of Geophysical Research: Atmospheres, Vol. 119, Issue 6; ISSN 2169-897X
• Publisher: American Geophysical Union
• Country of Publication: United States
• Language: English