| Summary: | The surface mass balance (SMB) of the Greenland Ice Sheet, the balance between snow accumulation and mass loss due to sublimation and runoff at the ice sheet surface, plays an important role in overall ice sheet mass balance, strongly impacting the ice sheet's contribution to sea level change. Energy and mass balance models, including sophisticated regional climate models capable of simulating regional atmospheric circulation patterns and surface-atmosphere interactions, can be used to estimate spatially and temporally continuous SMB changes, but require validation using in situ measurements, which are relatively sparse given logistical challenges. Measurements of snow and firn density are particularly important for validating models used to convert remote-sensing-measured ice sheet thickness changes into mass changes. Measurement of profiles of snow properties such as grain size, shape, and hardness can also be used to evaluate simulation of processes such as snowpack energy and mass transfer, and snow albedo. This dataset includes two profiles of snow density, grain size, and hardness collected near the Greenland Ice Sheet Summit Camp (at 79.60963 degrees North, 38.54980 degrees West) on June 26 and 27, 2010. The fieldwork was conducted with the goal of improving quantification of Greenland ice sheet surface mass balance through validation of surface energy and mass balance models, and to reduce model uncertainties through a model/field/satellite-based data assimilation framework. Additional goals were the improvement of electromagnetic modeling of active and passive microwave observations and calibration and calibration and assessment of measurements collected through the National Aeronautics and Space Administration's (NASA's) operation ICEBridge mission. The two profiles were collected after excavation of a large trench by a CH2MHILL support team on June 25, 2010. A first set of measurements was collected from a small (1.6 meter deep) profile on June 26, 2010 in a shallow part of the trench. Measurements included snow density measurements at regular depth intervals collected with a 250 cubic centimeter (cc) density cutter, visual grain size and shape identification from visual observation under a macroscope over a ruled card, and hand hardness measurements, and snow temperature measurements taken with a dial-stem thermometer. A second set of measurements was collected from a deeper (4.1 meter deep) profile on June 27, 2010. Measurements included snow density measurements at regular depth intervals collected with a 1000 cc density cutter, visual grain size and shape identification from visual observation under a macroscope over a ruled card, and hand hardness measurements.
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