Bergy Bit and Melt Water Trajectories in Godthåbsfjord (SW Greenland) Observed by the Expendable Ice Tracker

Abstract

Icebergs and bergy bits makes up a significant component of the total freshwater flux from the Greenland Ice Sheet to the ocean. Observations of iceberg trajectories are biased toward larger icebergs and, as a result, the drift characteristics of smaller icebergs and bergy bits are poorly understood. In an attempt to fill this critical knowledge gap, we developed the open-source EXpendable Ice TrackEr (EXITE). EXITE is a low-cost, satellite-tracked GPS beacon capable of high-resolution temporal measurements over extended deployment periods (30 days or more). Furthermore, EXITE can transform to a surface drifter when its host iceberg capsizes or fragments. Here we describe basic construction of an EXITE beacon and present results from a deployment in Godthåbsfjord (SW Greenland) in August 2016. Overall, EXITE trajectories show out-fjord surface transport, in agreement with a simple estuarine circulation paradigm. However, eddies and abrupt wind-driven reversals reveal complex surface transport pathways at time scales of hours to days.

Review Article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

“…Dust plumes from pro-glacial terrain supply glacial flour to the ocean on scales of >100 km and thus act as an important source of Fe to the ocean at high latitudes, where other atmospheric dust sources are scarce (Prospero et al, 2012;Bullard, 2013). Similarly, icebergs have long been speculated to act as an important source of Fe to the offshore ocean (Hart, 1934;Raiswell et al, 2008;Lin et al, 2011) and induce mixing of the surface ocean (Helly et al, 2011;Carlson et al, 2017). Whilst freshwater discharge is a driver of biogeochemical changes in nearshore and fjord environments downstream of glaciers, the distant (>100 km scale) biogeochemical effects of glaciers on the marine environment, are likely dominated by these alternative mechanisms (Fig.…”

“…Moving towards an observational Lagrangian framework will require the deployment of new technology such as the recent development of low-cost GPS trackers which, especially when combined with in situ sensors, may improve our understanding of the transport and mixing of heat, freshwater, sediments, and nutrients downstream of glaciers (Carlson et al, 2017;Carlson and Rysgaard, 2018). For example, GPS trackers deployed on 'bergy bits' have https://doi.org/10.5194/tc-2019-136 Preprint.…”

A State-of-the-Art Compact Surface Drifter Reveals Pathways of Floating Marine Litter in the German Bight

“…The wind slip is the horizontal motion of a drifter that differs from the motion of the surface currents and is caused by the direct wind forcing on the surface float (Lumpkin and Pazos, 2007). The wind slip U slip can be calculated as estimated in Suara et al (2015) and Carlson et al (2017a) by…”

Review article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

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