On the Greenland ice sheet, the sensible heat flux is the second largest source of energy for surface melt. Yet in atmospheric models, the surface turbulent heat fluxes are always indirectly estimated using a bulk turbulence parametrization, which needs to be constrained by long-term and continuous observations. Unfortunately, such observations are challenging to obtain in remote polar environments, especially over ablating ice surfaces. We therefore test a classical eddy-covariance method, based on propeller anemometers and thermocouple measurements, to estimate the momentum and sensible heat fluxes on the Greenland ice sheet. To correct for the high-frequency attenuation, we experimentally derive the sensor frequency-response characteristics and evaluate the universal turbulence spectra on the ice sheet. We show that the corrected fluxes are accurate and that the sampling interval can be reduced to 4 s to increase the system’s autonomy. To illustrate its potential, we apply the correction to one year of vertical propeller eddy-covariance measurements in the western ablation area of the ice sheet, and quantify the seasonal variability of the sensible heat flux and of the aerodynamic roughness length.

中文翻译：

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一种垂直螺旋桨涡流协方差方法及其在格陵兰冰盖表面湍流长期监测中的应用

在格陵兰冰盖上，显热通量是地表融化的第二大能量来源。然而，在大气模型中，地表湍流热通量总是使用体积湍流参数化来间接估计，这需要受到长期和连续观测的约束。不幸的是，在偏远的极地环境中，尤其是在消融的冰面上，很难获得这样的观测结果。因此，我们测试了一种基于螺旋桨风速计和热电偶测量的经典涡流协方差方法，以估计格陵兰冰盖上的动量和显热通量。为了校正高频衰减，我们通过实验推导出传感器频率响应特性并评估冰盖上的通用湍流光谱。我们表明校正后的通量是准确的，并且采样间隔可以减少到 4 秒以增加系统的自主性。为了说明其潜力，我们将修正应用于冰盖西部消融区一年的垂直螺旋桨涡度协方差测量，并量化显热通量和空气动力学粗糙度长度的季节性变化。