Deconstructing Eurasia's Wild Weather
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- Visualizations by:
- Trent L. Schindler
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- Written by:
- Adam P. Voiland
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- Scientific consulting by:
- Kyu-Myong Kim and
- William K. Lau
- View full credits
Normally the jet stream in the Northern Hemisphere carries weather fronts over Russia in four or five days. But late in the summer of 2010 conditions were anything but normal. A large-scale, stagnant region of high pressure developed and lingered over western Russia for about a month. The rare weather pattern—known to meteorologists as an Omega blocking high—split the jet stream in two, causing winds to flow around the high, an area of descending warm air, in a horseshoe-shaped pattern similar to that of the Greek letter Omega (Ω). The high blocked the normal progression of weather fronts and produced droughts and unusually warm temperatures that fueled a rash of fires near Moscow. As Russia burned, the same blocking pattern kept a low-pressure area over northern Pakistan. The cool, rising air of the low generated torrential rainfall and destructive flooding in northern Pakistan when it clashed with warmer air from the high. In the visualization below, look for the warm air from the persistent high-pressure zone over Russia (shown in yellow and red) and the cooler air from the low-pressure zone (shown in blue) just north of Pakistan.
Credits
Please give credit for this item to:
NASA's Goddard Space Flight Center
Images of Smoldering Fires in the Vicinity of Moscow and of Manchar Lake courtesy of Earth Observatory, NASA/GSFC
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Animator
- Trent L. Schindler (USRA) [Lead]
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Writer
- Adam P. Voiland (SSAI) [Lead]
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Scientists
- Kyu-Myong Kim (NASA/GSFC) [Lead]
- William K. Lau (Earth System Science Interdisciplinary Center, University of Maryland) [Lead]
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Producer
- Adam P. Voiland (SSAI)
Papers
This visualization is based on the following papers:Related pages
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ID: 3850 Visualization
Extreme Russian Fires and Pakistan Floods Linked Meteorologically
Read moreIn the summer of 2010, months of record-breaking drought and temperatures culminated with a rash of fires that ravaged western Russia for weeks. Temperatures in Moscow soared to an average of 104 °F (40 °C) during late July and early August — more than 18 °F (10 °C) above normal. Hundreds of fires broke out producing some $15 million in damages. The heat and smoke killed about 56,000 people, making the Russian wildfires fires one of the most lethal natural disasters of the year.Meanwhile, some 930 kilometers (1,500 miles) away, relentless rainfall was simultaneously pounding Pakistan and generating intense flooding. The Pakistan Meteorological Department reported nationwide rain totals 70 percent above normal in July and 102 percent above normal in August.New research conducted by William Lau, an atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Md., suggests the two seemingly disconnected events were actually closely linked.Under normal circumstances, the jet stream pushes weather fronts through Eurasia in four or five days, but something unusual happened in July of 2010. A large-scale, stagnant weather pattern — known as an Omega blocking event — slowed the Rossby wave over Russia and prevented the normal progression of weather systems from west to east.As a result, a large region of high-pressure formed over Russia trapping a hot, dry air mass over the area. As the high lingered, the land surface dried and the normal transfer of moisture from the soil to the atmosphere slowed. Precipitation ceased, vegetation dried out, and the region became a taiga tinderbox.Meanwhile, the blocking pattern created unusual downstream wind patterns over Pakistan. Areas of low pressure on the leading edge of the Rossby wave formed in response to the high, pulling cold, dry Siberian air into lower latitudes.This cold air from Siberia clashed with warm, moist air arriving over Pakistan from the Bay of Bengal as part of the monsoon. There's nothing unusual about moisture moving north over India toward the Himalayas. It's a normal part of the monsoon. However, in this case, the unusual wind patterns associated with the blocking high brought upper level air disturbances farther south than typical, which in effect helped shifted the entire monsoon system north and west.This brought heavy monsoon rains — centered over parts of India — squarely over the northern part of Pakistan, a region ill-prepared to handle large amounts of rain. ||
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