From the Ice Sheet to the Sea: An Interdisciplinary Study of the Impact of Extreme Melt on Ocean Stratification and Productivity near West Greenland

DESCRIPTION: While the potential impact of increasing meltwater from Greenland on global sea level is clear, another important implication is its potential impact on coastal ocean physics, biogeochemistry, and ecology. We propose here an interdisciplinary project (Ice Sheet Impact Study; ISIS) to understand how increasing meltwater runoff from the west Greenland Ice Sheet (GrIS) affects ocean productivity in the coastal waters of Greenland. In particular, we aim to understand how freshwater, sediment, and nutrient input from ice sheet runoff and surface fluxesimpact the evolution of seasonal stratification and ocean productivity differentially along the latitudinal gradient from the Labrador Sea to the Northwater polynya (Fig. 2). Data concerning runoff and surface melting recorded during 2012 (and in 2007 and 2010) offer extreme cases in which to evaluate the sensitivity of ocean stratification to extreme melting and mass loss. The coastal seas west of Greenland have experienced significant seasonal sea ice loss and associated reductions in primary productivity during the past decade (Arrigo and van Dijken. 2011). Wehypothesize that, depending on the content and mode of delivery, meltwater inputs from Greenland may compensate for these losses and support local regions of enhanced production once again. Since these productive waters are critical to large populations of endemic as well as migratory animals (Karnovksy et al. 2007) and humans depending on these natural resources, the implications for meltwater increases on these ocean ecosystems are global as well. Our approach employs a combination of remote sensing tools, computational models, and insitu data collected by international collaborators. Multiple NASA and non-NASA satellite data and sensors, including MODIS sea and ice surface temperature, Aquarius sea surface salinity.GRACE ice sheet mass balance, and SeaWiFS and MODIS/Aqua ocean color, will be used for assessing the extent of melt, its fate, and its impact between 1997 to 2016. We will use regional climate models (in which an atmospheric model is fully coupled to a snow energy and ice sheet mass balance model) in combination with a meltwater routing scheme. These, in turn, will be used in conjunction with a three dimensional numerical circulation model of the ocean and a phytoplankton growth model. Satellite data will also be used to set boundary conditions for models and evaluate their output. Field efforts by our international collaborators will provide ground truth data. Our proposed effort directly responds.