Process‐Based Model Evaluation Using Surface Energy Budget Observations in Central Greenland. Issue 10 (16th May 2018)

• Record Type: Journal Article
• Authors: Miller, Nathaniel B.; Shupe, Matthew D.; Lenaerts, Jan T. M.; Kay, Jennifer E.; de Boer, Gijs; Bennartz, Ralf
• Is Part Of: Journal of geophysical research. Volume 123:Issue 10(2018)
• Page Start: 4777
• Page End: 4796
• Publication Date: 2018-05-16
• Subjects: Greenland -- surface energy budget -- model evaluation; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2017JD027377
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Energy exchange at the Greenland ice sheet surface governs surface temperature variability, a factor critical for representing surface melt. Physical processes link driving forces to subsequent surface energy budget responses, including radiative, turbulent, and ground heat fluxes, and ultimately control surface temperature evolution. A reanalysis product (ERA‐Interim, ERA‐I), operational model (Climate Forecast System version 2, CFSv2), and climate model (Community Earth System Model, CESM) are evaluated using a comprehensive set of surface energy budget observations and process‐based relationships obtained at Summit, Greenland. Simulated downwelling longwave radiation is underestimated, which is linked to a deficiency of liquid‐bearing clouds. Lower than observed surface albedo, especially in ERA‐I, compensates for summer deficiencies in downwelling longwave radiation. In winter, such deficiencies are compensated by an overestimation of the sensible heat flux. Process‐based relationships convey that all three models underestimate the response of surface temperature to changes in radiative forcing, primarily due to an overactive ground heat flux response in ERA‐I, turbulent heat fluxes in CFSv2, and sensible heat flux in CESM. Cross comparison of three distinct models indicates that the ground heat flux response for ERA‐I, CFSv2, and CESM is too high, too low, and comparatively accurate, respectively, signifying the benefit of using an advanced representation of snow properties. Relatively small biases in CESM surface albedo suggest that advances in the representation of cloud microphysics result in more realistic radiative forcing. These results provide insight into model strengths and deficiencies, indicating the importance of representing physical processes when portraying cloud impacts on surface temperature variability. Key Points: Component and process‐based model evaluation is performed using surface energy budget observations at Summit, Greenland The surface temperature response to radiative forcing is underestimated in the evaluated models Cross‐model comparisons reveal the importance of representing radiative and thermal properties of the snowpack in models