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Evaluating EAMv2 simulated stratiform mixed-phase cloud properties at Northern and Southern high latitudes against ARM measurements
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  • Meng Zhang,
  • Shaocheng Xie,
  • Xiaohong Liu,
  • Damao Zhang,
  • Wuyin Lin,
  • Kai Zhang,
  • Jean-Christophe Golaz,
  • Xue Zheng,
  • Yuying Zhang
Meng Zhang
Lawrence Livermore National Laboratory

Corresponding Author:[email protected]

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Shaocheng Xie
LLNL
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Xiaohong Liu
Texas A&M University
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Damao Zhang
Pacific Northwest National Laboratory
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Wuyin Lin
Brookhaven National Laboratory (DOE)
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Kai Zhang
Pacific Northwest National Laboratory (DOE)
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Jean-Christophe Golaz
Lawrence Livermore National Laboratory (DOE)
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Xue Zheng
Lawrence Livermore National Laboratory (DOE)
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Yuying Zhang
Lawrence Livermore National Lab
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Abstract

This study evaluates high-latitude stratiform mixed-phase clouds (SMPC) in the atmosphere model of the newly released Energy Exascale Earth System Model version 2 (EAMv2) by utilizing one-year-long ground-based remote sensing measurements from the U.S. Department of Energy Atmospheric Radiation and Measurement (ARM) Program. A nudging approach is applied to model simulations for a better comparison with the ARM observations. Observed and modeled SMPCs are collocated to evaluate their macro- and microphysical properties at the ARM North Slope of Alaska (NSA) site in the Arctic and the McMurdo (AWR) site in the Antarctic. We found that EAMv2 overestimates (underestimates) SMPC frequency of occurrence at the NSA (AWR) site nearly all year round. However, the model captures the observed larger cloud frequency of occurrence at the NSA site. For collocated SMPCs, the annual statistics of observed cloud macrophysics are generally reproduced at the NSA site, while at the AWR site, there are larger biases. Compared to the AWR site, the lower cloud boundaries and the warmer cloud top temperature observed at NSA are well simulated. On the other hand, simulated cloud phases are substantially biased at each location. The model largely overestimates liquid water path at NSA, whereas it is frequently underestimated at AWR. Meanwhile, the simulated ice water path is underestimated at NSA, but at AWR, it is comparable to observations. As a result, the observed hemispheric difference in cloud phase partitioning is misrepresented in EAMv2. This study implies that continuous improvement in cloud microphysics is needed for high-latitude mixed-phase clouds.