Research Objectives:
This project represents a multi-institutional and multi-disciplinary effort to investigate the physical processes governing the behavior of giant tabular icebergs calved from Antarctica's ice shelves. Last year the main focus of the field program was the fleet of icebergs that are currently aground or adrift near Ross Island. This season, this focus will be expanded to include two ice-shelf or ice-tongue sites (one on the Ross Ice Shelf and the other known as the Drygalski Ice Tongue) that are expected to become new icebergs in the next several years.
The scientific rationale of the research is threefold: the first is the fact that the opportunity to investigate the basic principles governing the drift, melting, break-up and environmental impact (including generation of seismic signals) of large icebergs presents itself only rarely, and the calving of icebergs presently underway in the Ross Sea presents a once-in-a-lifetime opportunity. The second is the fact that the northward drift of large tabular icebergs represents a natural “climate change” experiment on an accelerated time-scale: the melting of the icebergs being studied over the next decade will foretell events that may occur in parts of Antarctica (e.g., the ice shelves) as global warming kicks in over the coming century. A third motivation is that large tabular icebergs from Antarctica represent a significant mass of fresh water -- an important natural resource of concern to humans. Understanding the natural drift patterns, and regions where icebergs accumulate near inhabited parts of the globe may someday prove useful for supplying fresh water to populations in need.
Project team members will deploy autonomous drift-tracking stations that report iceberg weather conditions, collect GPS data that tracks iceberg movements, and publish occasional webcam photographs through satellite connections to the internet. Seismometers are deployed on the icebergs to determine the source of T-phase seismic tremor. T-phase stands for “tertiary arrival” and is the name tentatively given by seismologists to the enigmatic acoustic signals generated by icebergs and picked up thousands of kilometers away in remote island outposts. Radar measurements, using both portable radar sounders and permanent in situ radar stations are conducted to determine the basal melting rate of the icebergs in response to the warmer ocean temperatures they will encounter as they drift north.
Data collected so far has helped to illuminate the causes and effects of the enigmatic drift pattern of B15A in the vicinity of Ross Island. Over the course of the next decade, instruments deployed on B15A and other icebergs will monitor their behavior as they drift far from the Ross Sea.
