TY - JOUR
T1 - Simulating surface energy fluxes using the variable-resolution Community Earth System Model (VR-CESM)
AU - Burakowski, Elizabeth A.
AU - Tawfik, Ahmed
AU - Ouimette, Andrew
AU - Lepine, Lucie
AU - Zarzycki, Colin
AU - Novick, Kimberly
AU - Ollinger, Scott
AU - Bonan, Gordon
N1 - Funding Information:
We would like to recognize the computational support provided by the NCAR Computational and Information Systems Laboratory for computing, processing, and data storage. We also thank two anonymous reviewers for their helpful comments to improve the manuscript.
PY - 2019/10/1
Y1 - 2019/10/1
N2 - Recent advances in variable-resolution (VR) global models provide the tools necessary to investigate local and global impacts of land cover by embedding a high-resolution grid over areas of interest in a seamless and computationally efficient manner. We used two eddy covariance tower clusters in the Eastern USA to evaluate surface energy fluxes (latent heat, λE; sensible heat, H; net radiation, Rn; and ground heat, G) and surface properties (aerodynamic resistance to heat transfer, raero; Bowen ratio, β; and albedo, α) by uncoupled point simulations of the land-only Community Land Model (PTCLM4.5) and two coupled land–atmosphere Community Earth System Model (CESM1.3) simulations. The CESM simulations included a 1° uniform grid global simulation and global 1° simulation with a 0.25° refined VR grid over the Eastern USA. Tower clusters included the following plant functional types—broadleaf deciduous temperate (hardwood) forest, C3 non-Arctic grass (grass), a cropland, and needleleaf evergreen temperate (pine) forest. During the growing season, diurnal cycles of λE and H for grass and the cropland were simulated well by PTCLM4.5 and VR-CESM1.3; however, λE (H) was biased low (high) at the hardwood and pine forested sites, contributing to biases in β. Growing season Rn was generally well simulated by CLM4.5 and VR-CESM1.3; however, modeled elevated albedo (indicative of snow cover) persisted longer in winter and spring leading to large biases in Rn and α. The introduction of a VR grid does not adversely impact surface energy fluxes compared to 1° uniform grids and highlights the usefulness of this approach for future efforts to predict land–atmosphere fluxes across heterogeneous landscapes.
AB - Recent advances in variable-resolution (VR) global models provide the tools necessary to investigate local and global impacts of land cover by embedding a high-resolution grid over areas of interest in a seamless and computationally efficient manner. We used two eddy covariance tower clusters in the Eastern USA to evaluate surface energy fluxes (latent heat, λE; sensible heat, H; net radiation, Rn; and ground heat, G) and surface properties (aerodynamic resistance to heat transfer, raero; Bowen ratio, β; and albedo, α) by uncoupled point simulations of the land-only Community Land Model (PTCLM4.5) and two coupled land–atmosphere Community Earth System Model (CESM1.3) simulations. The CESM simulations included a 1° uniform grid global simulation and global 1° simulation with a 0.25° refined VR grid over the Eastern USA. Tower clusters included the following plant functional types—broadleaf deciduous temperate (hardwood) forest, C3 non-Arctic grass (grass), a cropland, and needleleaf evergreen temperate (pine) forest. During the growing season, diurnal cycles of λE and H for grass and the cropland were simulated well by PTCLM4.5 and VR-CESM1.3; however, λE (H) was biased low (high) at the hardwood and pine forested sites, contributing to biases in β. Growing season Rn was generally well simulated by CLM4.5 and VR-CESM1.3; however, modeled elevated albedo (indicative of snow cover) persisted longer in winter and spring leading to large biases in Rn and α. The introduction of a VR grid does not adversely impact surface energy fluxes compared to 1° uniform grids and highlights the usefulness of this approach for future efforts to predict land–atmosphere fluxes across heterogeneous landscapes.
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U2 - 10.1007/s00704-019-02785-0
DO - 10.1007/s00704-019-02785-0
M3 - Article
AN - SCOPUS:85062021438
VL - 138
SP - 115
EP - 133
JO - Theorectical and Applied Climatology
JF - Theorectical and Applied Climatology
SN - 0177-798X
IS - 1-2
ER -