We present the first direct comparison of turbulence conditions measured simultaneously over exposed ice and a 0.08 m thick supraglacial debris cover on Suldenferner, a small glacier in the Italian Alps. Surface roughness, sensible heat fluxes (~20–50 W m−2), latent heat fluxes (~2–10 W m−2), topology and scale of turbulence are similar over both glacier surface types during katabatic and synoptically disturbed conditions. Exceptions are sunny days when buoyant convection becomes significant over debris-covered ice (sensible heat flux ~ −100 W m−2; latent heat flux ~ −30 W m−2) and prevailing katabatic conditions are rapidly broken down even over this thin debris cover. The similarity in turbulent properties implies that both surface types can be treated the same in terms of boundary layer similarity theory. The differences in turbulence between the two surface types on this glacier are dominated by the radiative and thermal contrasts, thus during sunny days debris cover alters both the local surface turbulent energy fluxes and the glacier component of valley circulation. These variations under different flow conditions should be accounted for when distributing temperature fields for modeling applications over partially debris-covered glaciers.

中文翻译：

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暴露和碎片覆盖的冰川冰上湍流结构和能量通量的比较

我们首次直接比较了在意大利阿尔卑斯山的一个小冰川 Suldenferner 上暴露的冰和 0.08 m 厚的冰上碎片覆盖层上同时测量的湍流条件。表面粗糙度、显热通量 (~20–50 W m-2），潜热通量（~2-10 W m-2)，在下沉和天气扰动条件下，两种冰川表面类型的拓扑和湍流规模相似。例外情况是晴天，此时浮力对流在碎片覆盖的冰上变得显着（感热通量 ~ -100 W m-2; 潜热通量 ~ -30 W m-2) 和普遍的下垂条件即使在这个薄薄的碎片覆盖物上也会迅速分解。湍流性质的相似性意味着根据边界层相似性理论，两种表面类型都可以被同等对待。该冰川上两种表面类型之间的湍流差异主要由辐射和热对比决定，因此在晴天时，碎屑覆盖会改变当地表面湍流能量通量和山谷环流的冰川成分。在为部分碎片覆盖的冰川上的建模应用分配温度场时，应考虑不同流动条件下的这些变化。