We enhance the Community Land Model (CLM) snow albedo modeling by implementing several new features with more realistic and physical representations of snow-aerosol-radiation interactions. Specifically, we incorporate the following model enhancements: (a) updating ice and aerosol optical properties with more realistic and accurate data sets, (b) adding multiple dust types, (c) adding multiple surface downward solar spectra to account for different atmospheric conditions, (d) incorporating a more accurate adding-doubling radiative transfer solver, (e) adding nonspherical snow grain representations, (f) adding black carbon-snow and dust-snow internal mixing representations, and (g) adding a hyperspectral (480-band vs. the default 5-band) modeling capability. These model features/enhancements are included as new CLM physics/namelist options, which allows for quantification of model sensitivity to snow albedo processes and for multi-physics model ensemble analyses for uncertainty assessment. The model updates have been included in the latest released CLM version. Sensitivity analyses reveal strong impacts of using the new adding-doubling solver, nonspherical snow grains, aerosol-snow internal mixing, updated aerosol optics, and different dust types. These enhanced snow albedo representations improve the CLM simulated global snowpack evolution and land surface conditions, with reduced biases in simulated snow surface albedo, snow cover, snow water equivalent, snow depth, and surface (2-m) air temperature over many mid-latitude mountainous regions and seasonal snowpacks but degraded performance in some northern high-latitude regions.

中文翻译：

---

社区土地模型 (CLM5) 雪反照率建模的新功能和增强功能：描述、灵敏度和评估

我们通过实施几个新功能来增强社区土地模型（CLM）雪反照率建模，这些新功能具有更真实和物理的雪-气溶胶-辐射相互作用表示。具体来说，我们采用了以下模型增强功能：（a）使用更真实和准确的数据集更新冰和气溶胶的光学特性，（b）添加多种灰尘类型，（c）添加多个表面向下太阳光谱以考虑不同的大气条件， (d) 结合更精确的加倍辐射传输求解器，(e) 添加非球形雪粒表示，(f) 添加黑碳雪和尘雪内部混合表示，以及 (g) 添加高光谱（480 波段）与默认的 5 频段）建模功能相比。这些模型功能/增强功能作为新的 CLM 物理/名单选项包含在内，允许量化模型对雪反照率过程的敏感性，并进行多物理模型集成分析以进行不确定性评估。模型更新已包含在最新发布的 CLM 版本中。灵敏度分析揭示了使用新的加倍解算器、非球形雪粒、气溶胶-雪内部混合、更新的气溶胶光学器件和不同灰尘类型的强烈影响。这些增强的雪反照率表示改善了 CLM 模拟的全球积雪演化和地表条件，减少了许多中纬度地区模拟雪面反照率、积雪、雪水当量、雪深和地表 (2 米) 气温的偏差山区和季节性积雪，但在一些北部高纬度地区性能下降。