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- Title
Evaluating EAMv2 Simulated High Latitude Clouds Using ARM Measurements in the Northern and Southern Hemispheres.
- Authors
Zhang, Meng; Xie, Shaocheng; Liu, Xiaohong; Zhang, Damao; Lin, Wuyin; Zhang, Kai; Golaz, Jean‐Christophe; Zheng, Xue; Zhang, Yuying
- Abstract
This study evaluates high latitude stratiform mixed‐phase clouds (SMPC) in the atmosphere model of the Energy Exascale Earth System Model version 2 (EAMv2) by utilizing one‐year‐long ground‐based remote sensing measurements from the Atmospheric Radiation and Measurement (ARM) program. A nudging approach is applied to model simulations for a constrained comparison with the ARM observations. Observed and modeled SMPCs are sampled and collocated to address the difference in data resolution, so that we can consistently evaluate their macrophysical properties at the North Slope of Alaska (NSA) site in the Arctic and the McMurdo (AWR) site in the Antarctic. We found that EAMv2 overestimates SMPC frequency of occurrence at both sites. 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 top and cloud base and the warmer cloud top temperature observed at NSA are well simulated. On the other hand, simulated cloud phase is substantially biased. The model largely overestimates liquid water path, and the ice water path is underestimated at NSA, but at AWR, the liquid water path is frequently underestimated due to the dominance of snow in Antarctic SMPCs. As a result, the observed hemispheric difference in cloud phase partitioning is misrepresented in EAMv2. This study implies that additional model development is needed for high latitude mixed‐phase clouds. Plain Language Summary: Stratiform mixed‐phase clouds (SMPCs) contain both liquid droplets and ice crystals at temperatures between −40° and 0°C. These clouds are ubiquitous at high latitudes and can largely impact global climate change. This study evaluates how well the SMPCs are simulated in the newly released second version of the Energy Exascale Earth System Model atmosphere model (EAMv2) by comparing simulated cloud properties to ground‐based observations. Observed cloud properties are obtained at two high latitude sites in the Arctic and Antarctic, respectively. The meteorological states in model simulations are constrained toward reality to allow a consistent comparison between the model and observations. We find that EAMv2 reasonably simulates the more frequent occurrences of SMPCs, the higher cloud top and cloud base, and the warmer cloud top temperature at the Arctic site than at the Antarctic site, consistent with the observations. However, the model overly simulates the SMPC occurrences at both sites compared to observations. Biases in simulated cloud boundaries are also found, particularly in the Antarctic. Moreover, the simulated cloud phase partitioning, the fraction of liquid‐phase water to ice‐phase water, is substantially biased. This study implies the requirement of additional model development for high latitude mixed‐phase clouds. Key Points: Stratiform mixed‐phase clouds sampled from the Energy Exascale Earth System Model version 2 nudged simulation are consistently evaluated with ground‐based remote sensing dataCloud boundary properties and their hemispheric difference are better simulated than the cloud phaseCloud phase is largely biased, with an opposite hemispheric difference feature in supercooled liquid fraction compared to observations
- Subjects
ATMOSPHERIC radiation measurement; STRATUS clouds; ATMOSPHERIC models; SUPERCOOLED liquids; PHASE partition; LATITUDE
- Publication
Journal of Geophysical Research. Atmospheres, 2023, Vol 128, Issue 15, p1
- ISSN
2169-897X
- Publication type
Article
- DOI
10.1029/2022JD038364