University of Missouri atmospheric science researchers will team with their counterparts at the A.M.Obukhov Institute of Atmospheric Physics of the Russian Academy of Sciences in a three million Russian ruble project to study the phenomena of atmospheric blocking.
The MU School of Natural Resources, home to the Department of Soil, Environmental and Atmospheric Sciences (SEAS), recently agreed to jointly create prediction models of the little-understood weather event known to trigger persistent periods of stagnant and sometimes dangerous weather.
MU researchers will develop new methods of spotting and predicting atmospheric blocking, and analyze the social and economic impacts that blocking events caused during the 20th century, said Tony Lupo, professor and SEAS chair. Lupo will lead MU’s part of the investigation.
A.M.Obukhov Institute scientists will mine existing scientific literature looking for new clues, create computer prediction models and analyze the influence of anticyclones on blocking events.
A Little Known but Dangerous Phenomena
Blocking occurs when a powerful high-pressure area, which usually moves west to east, gets stuck in one place. Following pressure areas grind to a halt behind it – sometimes for several days or even weeks.
Several cases of atmospheric blocking prompted the research interest. Last summer in Russia, a blocking event set heat records and killed more than 15,000 people, Lupo said. “There were so many forest fires that pollution levels soared even into the Moscow region,” he continued.
Another event was the 2003 European heat wave where a stagnant pattern contributed to 35,000 deaths over the summer. Still another case, nicknamed Baked Alaska by researchers, occurred in 2004. Here, abnormally high temperatures and less-than-normal summer precipitation led to glacial melting. The persistent dry weather in the state's interior region led to fierce forest fires.
In the Baked Alaska event, a large high-pressure area stopped near Greenland. Weather systems over America slowed or stopped as far back as the Pacific Ocean. Normal weather movement resumed when the Greenland pressure area finally weakened.
Hot Summers, Cold and Snowy Winters
Blocking events can trigger dangerous conditions when tied to harsh weather. “If hot and dry weather becomes parked, short-term drought conditions can result,” Lupo said. “A stationary rainy pattern could lead to flooding.”
Blocking can also can bring good weather, Lupo pointed out. A blocking event in 2004 brought prolonged sunny skies and pleasant temperatures to the Midwest. “This resulted in excellent corn and soybean yields,” he said.
In America, the coldest winters on record are usually due to blocking, Lupo said. The unusual cold outbreak in April 2007 in Missouri that killed budding plants was due to a blocking event. The persistent hot summer of 2011 that cooked the American Midwest was also caused by a blocking event.
A typical blocking event lasts 8-11 days, Lupo said, although some have lasted as long as 35 days. Several blocking events can also occur in succession. The 2003 event in Europe was so deadly because three blocking events occurred in a row.
About 20-40 blocking events occur each year, Lupo explained. The greatest number occurs over Siberia, east of the Urals. Current weather forecast models are of little help in predicting blocking events, even a day or two in advance, much less the 30 days of advance warning that forecasters would like to provide. Lupo hopes the research will add clues that would help forecasters better predict blocking.
Lupo has been studying atmospheric blocking for more than 20 years and has authored more than 20 scientific papers on the subject. Lupo is a Fellow of the Royal Meteorological Society in London. In 2005, he was selected as a Fulbright Scholar and spent a summer at the Russian Academy of Science working with fellow climate scientists. Lupo is a member of the International Panel of Climate Change that shared the 2007 Nobel Peace Prizewith Al Gore.
A high-altitude weather map centered on the North Pole shows the December-January blocking event that brought persistent cold and snowy weather to America (bottom). A large high-pressure system over Greenland (right) blocked the usual west-to-east movement of storms. The blue arrow shows the southern movement of cold air from the pole that would have otherwise moved eastward, but was blocked by the Greenland system. This blocking event was unusual as a second high-pressure system (left) stopped in the Northern Pacific area. Illustration courtesy NOAA via Tony Lupo.