Wednesday, March 16, 2011

Siberia's Lake Baikal Feeling the Heat


The "Butterfly Effect" the idea that on a global scale, even small events can have a ripple effect around the world is demonstrated in the work of a Russian family in Siberia that have for three generations studied Lake Baikal -- one of the most biologically diverse of the world's oldest and deepest lakes. In the 1940's, Mikhail Kozhov began taking detailed measurements of the lake's temperature. His granddaughter, Lyubov Izmest'eva, continues the family tradition.
Izmest'eva ventures out onto the water, or ice in the winter, to collect water samples and measure temperatures, just like her mother and grandfather before her.
Along with a team of scientists from the University of California at Santa Barbara, Izmest'eva recently co-authored a study of Lake Baikal. The research sheds light on the way climate change is affecting temperatures in large bodies of water.
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"This consistent dedication to understanding one of the world's most majestic lakes helps us understand not only the dynamics of Lake Baikal over the past 60 years, but also to recognize future scenarios for Lake Baikal,” said lead author Steve Katz in a University of California at Santa Barbara press release.
"This work is important because we need to go beyond detecting past climate variation,” said Stephanie Hampton of the University of California at Santa Barbara in a press release by that school.
"We also need to know how those climate variations are actually translated into local ecosystem fluctuations and longer-term local changes. Seeing how physical drivers of local ecology –– like water temperature –– are in turn reflecting global climate systems will allow us to determine what important short-term ecological changes may take place, such as changes in lake productivity,” said Hampton.
“They also help us to forecast consequences of climate variability,” Hampton said.
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The researchers found correlations between the lake and distant parts of the Earth. The results will help scientists understand how distant climate patterns affect the weather in central Asia.
For example, they found that changes in Lake Baikal's temperature varied along with monthly El Niño variations in the surface temperature of the Pacific Ocean, thousands of miles away.
The researchers also found connections between the jet stream and Lake Baikal. Three months after changes in the jet stream's strength and direction seasonal changes began to occur at the lake. Also, a less powerful jet stream resulted in less extreme cold spells in Lake Baikal.
Overall they found the lake is warming, but didn't find evidence of early springs or late winters.
The lake's temperature even reflected decade-scale changes in the Earth's rotation. Changes in the speed of Earth's rotation result in changes in the atmospheric zonal winds, the winds that travel east to west. The zonal winds affect the amount of energy available in the atmoshpere to cause storms in central Asia. And those long-term changes showed up in the Lake Baikal temperature record.
All of these forces influence each other and created a complex pattern of climate interactions. Lower El Niño forces correlated with a stronger Siberian high pressure center and a stronger jet stream flow. That resulted in more frequent cold snaps heading southeast across East Asia, including Lake Baikal, and more intense surface winds.
But even with the new understanding of climate interactions, some of the temperature changes in Lake Baikal remain unexplained.

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