Sunday, November 19, 2000

Solar flare shuts down continental communications

Published in the Antarctic Sun

MacOps bills itself as the Voice of Antarctica. The radio operators there talk to people all over the continent and elsewhere around the world on high-frequency and very high-frequency radios.

Thursday, just before lunch, the continent got a sore throat.

All the HF radios went quiet, broadcasting white noise instead of voices from all over.

“It was pretty eerie,” said Paula Elliott of MacRelay, which also monitors all radio frequencies.

A solar flare had sent a mass of charged particles out from the sun into the Earth’s atmosphere. Those charged particles had disrupted the ionosphere, the layer of Earth’s atmosphere that
reflects HF radio waves, preventing transmission of HF waves around the globe.

The radiation, the fourth largest storm of its type since 1976, caused some rearrangement
of communications and transport schedules on the continent.

“Camps were unable to check in,” Elliott said. “People were technically overdue for their
check-ins, though we knew why.”

If camps miss their check-ins under normal circumstances, rescue missions are launched. This
time, though, radio operators waited and worked around the situation.

They had lost contact with South Pole Station, Byrd Surface Camp, Siple Dome, Byrd Glacier, as well as the Olympus Range and Lake Vida, which are in VHF “dead spots” in the Dry Valleys.

Communications with the Pole were possible on the Internet during the Pole’s satellite window. The people at Vida had to climb a hill to hit a VHF repeater.

“We didn’t expect it to be as big as it was,” said MacOps coordinator Shelly DeNike.

The camp at Icestream C was put in during the communications blackout.

Normally, an airplane can’t leave a camp put-in until the camp radios MacOps on HF. This time, though, the camp was only able to talk to the plane on the ground. The solar flare’s energy prevented them from talking farther away.

Other than that small glitch, everything was fine.

“We’ve been pretty much prepared for this to happen,” DeNike said.

The larger field camps have emergency beacons they can set off if all else fails, just like if an aircraft crashes or a boat is in distress at sea. Had anything truly disastrous happened, they could have activated the beacon.

After two days without contact from Byrd Surface Camp, an airplane went out of its way to fly over it to make contact. Pilots helped by contacting camps along their flight routes.

“When they would fly in the vicinity of field camps they would call them,” DeNike
said.

Camp managers knew this might be a problem. Before going into the field, they had been briefed that HF problems might occur in this year of high solar activity.

In terms of air traffic control, everything also went smoothly with what air traffic manager Dusty Barrett called “a little bit of creative scheduling.”

Before planes left McMurdo, controllers gave pilots instructions for flying both to and from the Pole; normally they clear flights for only one direction at a time. MacCenter, the hub of air traffic control at McMurdo was only able to talk to the planes while they were within line-of-sight.

In a contingency set up last year, they had two controllers in Christchurch, New Zealand.

The controllers in McMurdo talked over the phone to Christchurch, which relayed messages over a satellite communication link to the planes.

“Once the HF went down we had to be a little bit creative,” Barrett said.

They also used Iridium satellite phones, Barrett said. Pilots continued to use HF, sending their position reports “in the blind,” without knowing if they were received, in the hope that MacCenter could hear them.

“Sometimes you can receive but you can’t transmit,” Barrett said.

This is the second full blackout since Winfly, but there have been partial blackouts where only lower frequencies were cut off.

This type of event has happened in the past, but only for 24 to 48 hours, Elliott said. This time it was Saturday evening before things came back, a shutdown of nearly 60 hours.

“We’ve seen a lot more activity than we had last year,” Elliott said.

It may have to do with a peak in the 11-year cycle of solar activity. Sometimes these effects from flares are predictable, and this time there was some warning. But the loss of HF communications was rapid.

“It happened right away,” DeNike said.

Things are back to normal now, Elliott said, but it could happen again anytime, and without a lot of warning.

“They hit without much notice,” she said.

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