AGU: Geophysical Research Letters

 

Editors' Highlight

Antarctic iceberg breakups possibly caused by storm-induced sea swells from far away

Many abrupt, millennial-scale shifts in past global climate are known to be associated with sudden releases of icebergs into the global ocean. To study iceberg calving, drift, melting, and disintegration, MacAyeal et al. (2006) deployed seismometers on Antarctica's Ross Ice Shelf and on various icebergs adrift in the Ross Sea. They found that low-frequency energy ranges, typically associated with storm swells, dominated the signal, causing the authors to hypothesize that storms in the northern and tropical Pacific Ocean influence calving and iceberg breakup. To show this, the authors focused on a strong storm in the Gulf of Alaska on 21 October 2005, and traced swells from this storm to a large Ross Sea iceberg immediately prior to, and during, its breakup on 27 October 2005. On the basis of these observations, the authors noted that a teleconnection might exist between the Antarctic ice sheet mass balance and weather systems worldwide, and that similar mechanisms might have triggered past climate shifts.

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