Modeling soil temperature in a temperate region: A comparison between empirical and physically based methods in SWAT
Although Soil and Water Assessment Tool (SWAT) has been widely used in temperate regions, the performance of its soil temperature module has not been extensively assessed. The aim of the present study was to evaluate the performance of the SWAT model’s built-in empirical soil temperature module and a physically-based soil temperature algorithm using four years of daily soil temperature measurements at three depths (i.e., 5, 10, and 50 cm) across 10 monitoring stations in and around the Choptank River watershed, Maryland, USA. Two versions of physically-based soil temperature module were considered: one was calibrated using parameter values adopted from previous studies, another one remained calibrated. Results show that the empirical soil temperature module and both versions of physically-based soil temperature module reproduce well variations of measured soil temperatures at 5 and 10 cm depths for all stations in non-winter seasons. However, the empirical and uncalibrated physically-based soil temperature modules tended to underestimate soil temperatures in non-winter seasons at the deeper soil layer (50 cm depth); they also severely underestimated soil temperatures in winter for soil surface layers (5 and 10 cm depths). Results indicate that the calibrated physically-based soil temperature module improved soil temperature simulation, especially for winter due to its accounting for insulation effect of crop residue on soil surface. This study suggested that when equipping a physically-based soil temperature module in a hydrological model, a better representation of surface residue was needed for applications in agricultural watersheds and assessing best management practices.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1502129
- Report Number(s):
- PNNL-SA-137086
- Journal Information:
- Ecological Engineering, Journal Name: Ecological Engineering Journal Issue: C Vol. 129; ISSN 0925-8574
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
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