Snow and ice melts are changing the arctic atmosphere

Sept. 20 (UPI) -- How are snow and ice melts impacting the atmosphere and climate in the Arctic? Scientists at the University of Alaska Fairbanks' Geophysical Institute are trying to find out.

Warming temperatures and earlier more dramatic snow and ice melts are impacting the Arctic's bromine season, a unique atmospheric process. In the springtime, low temperatures and snow-covered sea ice encourage the concentration of bromine in the atmosphere. The gas reacts with and breaks down ozone, yielding bromine monoxide and oxidizing mercury.

But bromine events become less common in the summer as temperatures rise and melting increases. In the offseason, bromine levels in the atmosphere decrease.

"Atmosphere chemistry really changes when snow melts," William R. Simpson, a professor of chemistry at UAF, said in a news release. "And earlier melt is changing what is happening in the atmosphere."

Using a year-long dataset describing weather, ocean and atmospheric conditions in the Arctic, researchers analyzed correlations between changes in sea ice and bromine reactivity.

"Monitoring the seasonal end date each year could give us an indication of climate change as well, since it correlates to temperature change," student researcher Justine A. Burd said. "Is the bromine season ending earlier each year, staying approximately the same, or getting longer?"

Across the Arctic, the melt season has gotten longer by an average five days per decade for the last 60 years. The new research -- detailed in the journal Atmospheres -- suggests bromine season has become shorter as the Arctic springtime is squeezed by a longer melt season.

"Knowing how snow and ice affect the atmosphere is becoming even more important considering the changing Arctic ice pack and changing Arctic temperatures," said Simpson. "This narrow work is one part of a big, broad question: what happens when snow starts to melt?"