Wind-driven upwelling around grounded tabular icebergs

Alon Stern, Eric Johnson, Till Wagner, David Holland, Peter Wadhams, C. Richard Bates, Povl Abrahamsen, Keith Nicholls, Anna Crawford, Jonathan Gagnon, Jean-Eric Tremblay

Research output: Contribution to journalArticlepeer-review

Abstract

Temperature and salinity data collected around grounded tabular icebergs in Baffin Bay in 2011, 2012 and 2013 indicate wind-induced upwelling at certain locations around the icebergs. These data suggest that along one side of the iceberg, wind forcing leads to Ekman transport away from the iceberg, which causes upwelling of the cool saline water from below. The upwelling water mixes with the water in the thermocline, causing the mixed layer to become cooler and more saline. Along the opposite side of the iceberg, the surface Ekman transport moves towards the iceberg, which causes a sharpening of the thermocline as warm fresh water is trapped near the surface. This results in higher mixed layer temperatures and lower mixed layer salinities on this side of the iceberg. Based on these in situ measurements, we hypothesize that the asymmetries in water properties around the iceberg, caused by the opposing effects of upwelling and sharpening of the thermocline, lead to differential deterioration around the iceberg. Analysis of satellite imagery around iceberg PII-B-1 over a six month monitoring period reveals differential decay around the iceberg, in agreement with this mechanism.
Original languageEnglish
Pages (from-to)5820-5835
JournalJournal of Geophysical Research - Oceans
Volume120
Issue number8
DOIs
Publication statusPublished - 24 Aug 2015

Keywords

  • Iceberg
  • Upwelling
  • Ekman

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