| Summary: | The effort to study polar regions using modern observational techniques is formally known and funded under the Polar Earth Observing Network (POLENET). In Greenland, the GNET project, or Greenland Network, was developed to establish a network of GPS receivers operating continuously and autonomously on stable bedrock around Greenland. The purpose of the January 26-27, 2017 workshop was to discuss the future of this network. We were especially focused on documenting how GNET is used now, how the network could evolve, and to ask what scientific questions motivate its future. GNET data have served many purposes, such as providing ground truth for predictive models for post glacial rise/fall of bedrock adjacent to the ice sheet that in turn, play an essential role in correcting satellite gravity and altimetry based estimates of ice mass balance on decadal time scales. In addition to enumerating past successes of GNET, we examined the value that the network may provide for new science, such as tropospheric and ionospheric mapping, gaining new insights concerning surface mass balance, ice dynamics and ocean tidal mapping among others. This workshop report is designed to capture some of these new explorations. There is an emphasis placed upon the components of ice sheet surface mass balance in this report. This is motivated by three recent science breakthroughs: Since about 2006, the negative mass balance of the Greenland ice sheet is dominated by melt processes Recent findings demonstrate that GNET have sensitivities to the loading components of the various elements of the surface mass balance The zenith-delays measured in the carrier phase of the electromagnetic pulses received at the stations are capable of significantly improving hindcast models of precipitation, fundamental to surface mass balance The primary recommendations of this report are: Continue to support the continuous and autonomous operation of the current configuration of GNET. The spatial distribution and long time series of observations has enabled a wealth of scientific discovery, and extending these time series enables new science Maximize the utility of the current data by encouraging low-latency access to data Encouraging new uses of GNET data, such as tropospheric zenith delay analyses to improve atmospheric models in Greenland and use of these data for modeling the ionosphere If possible, densify the current network to better resolve those areas of maximum gradient in glacial isostatic adjustment (GIA), and/or regions of rapid glacier change
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