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Posted on 10/31/2001 12:09:18 PM PST by Monitor

AUCKLAND - Global warming might be a popular worry but scientists on Antarctica's coast this southern summer are recording some of the thickest sea ice ever seen, the Antarctic Sun newspaper reported today.

New Zealand's Scott Base and the US McMurdo Sound on Ross Island were blocked in by heavy sea ice, apparently the result of a vast iceberg, the paper reported in its latest edition.

On the other side of the continent, a US research ship in Marguerite Bay on the Antarctic Peninsula has just managed to free itself from extensive ice fields.

The Antarctic Sun, published by Raytheon Polar Services at McMurdo, said an iceberg labelled B15 extended about 300 metres below sea-level, blocking the current of water that usually circulates through McMurdo Sound.

When it first calved off the Ross Sea ice shelf in March last year, B15 measured around 11,000 square kilometres, the size of Jamaica.

At the time it was believed it would drift out into the Southern Ocean and break up, but instead the latest satellite photos Monday showed B15, and the much smaller C16, were parked across McMurdo Sound.

"It's turned this whole area into a mill pond," Ted Dettmar, lead instructor at Field Safety Training Program at McMurdo, told the Sun.

In many years, winter storms blow out the sea ice, leaving open water in July, Dettmar said.

By the time the US Coast Guard ice breakers arrive in December, the ice edge is typically 24 to 32 km away from McMurdo Station.

But this year people wintering at McMurdo Station did not see any open water because of the ice, Dettmar said.

The sea ice was now three metres thick in front of McMurdo, and three to 4.4 metres thick at the Williams Field ice runway, west of Scott Base.

An ice breaker may have to cut through more than 113 km of ice to reach McMurdo.

Dettmar said the ice was flat, without pressure ridges and cracks.

It was also affecting penguins and seals which now have to travel further to access the sea.

A science group studying Weddel seals has found less than 150 adults in the study area, which extends from Scott Base to Cape Evans.

This is less than a third of the number seen by this time last year, said seal scientist Michael Cameron.

"We've known that there's a relationship between ice extent and the number of animals in the study area," Cameron said.

"To my knowledge this is the greatest summer sea ice extent that's ever been recorded in McMurdo Sound," Cameron said.

"Everybody's guess is that it's due to this giant iceberg off of Cape Bird blocking the swells that would normally break up any sea ice in the area."

Last year the sea ice near McMurdo was 40 per cent thicker than usual, and this year it's thicker still.

Meanwhile researchers aboard Nathaniel B Palmer off the Antarctic Peninsula also found heavy ice. They were held in it for several weeks, unable to move.

"They're fine, they're safe, they're doing science," said Al Hickey, marine superintendent for Raytheon Polar Services Company.

"They're just going to play a waiting game. The ship's in no jeopardy, the people are in no jeopardy."

The figure above shows the monthly temperature deviations from a seasonally adjusted average for the lower stratosphere - Earth's atmosphere from 14 to 22 km (9 to 14 miles). Red is an increase in the temperature from the average, and blue is a decrease in temperature. The large increase in 1982 was caused by the volcanic eruption of El Chichon, and the increase in 1991 was caused by the eruption of Mt. Pinatubo in the Philippines. September 1996 was the coldest month on record for stratospheric temperature.

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