To better understand and quantify the impact of clouds on the Greenland Ice Sheet surface mass balance (SMB), we study the spatiotemporal variability of the cloud radiative effect (CRE). The total CRE is separated in short-term and long-term impacts by performing multiple simulations with the SNOWPACK model for 2001-+2010. The annual total CRE is 16.8 ± 4.5 W m−2, reducing the SMB with −157 ± 3.8 Gt yr−1. Summer cloud radiative cooling is −6.4 ± 5.7 W m−2 in the ablation area, increasing the SMB with 121 ± 2.2 Gt yr−1. The annual integrated impact is cloud-reduced SMB of −36 Gt yr−1. The short-term effect dominates the opposing long-term effects through the albedo-melt feedback. A long-term warming effect decreases the albedo and so preconditions the surface for enhanced (summer) melt. The impact of the CRE, determined by spatial, temporal and initial conditions, explains existing conflicted views on the role of cloud radiation and emphasizes the need for accurate cloud and albedo representations in future studies.

中文翻译：

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云辐射对格陵兰冰盖表面物质平衡影响的时空变异性

为了更好地理解和量化云对格陵兰冰盖表面质量平衡 (SMB) 的影响，我们研究了云辐射效应 (CRE) 的时空变化。通过使用 2001-+2010 年的 SNOWPACK 模型进行多次模拟，总 CRE 被分为短期和长期影响。年度总 CRE 为 16.8 ± 4.5 W m-2，使 SMB 减少 -157 ± 3.8 Gt yr-1。消融区域的夏季云辐射冷却为 -6.4 ± 5.7 W m-2，使 SMB 增加 121 ± 2.2 Gt yr-1。年度综合影响是 -36 Gt yr-1 的云减少 SMB。通过反照率-熔体反馈，短期效应主导了相反的长期效应。长期的变暖效应降低了反照率，因此为增强（夏季）融化的表面做好了准备。CRE 的影响，由空间决定，