Monday, December 27, 2010

Climate Change Why Cooler in Europe and East Coast Fits Warming Model or Not

Tags: Climate Change Predicts Cooling on East Coast and Europe or Not, Judah Cohen

I think Judah Cohen, as bright as he think he is, wrongly states that the climate models do not consider a number of factors including cooling in certain parts of the world. Most of the climate models including the British, American, and Japanese, arguably the best models do not completely agree with each other, but they do predict cooling in the eastern USA and Europe due to Climate Change changing both the flow directions of oceans and jet stream directions.

The central Pacific Ocean warming nearer the equator in recent years has made the so-called seasonal weather effects, a specialty of Cohen’s, to become even more complex. We are now suffering La Nina effects, something Cohen fails to mention in his article, which is now causing heavy rain and snows in the California Mountains and the Cascades in Oregon and Washington, and unprecedented floods in California.

The other factor Cohen does not consider is the Gulf current slow down in the Atlantic, possibly due to Greenland land glaciers melting faster than usual making the ocean less salty. For example, Spain is at the same latitude as New York City, but Europe normally has not suffer the Arctic chills until now. What happened is the Warming Gulf Current flows from the Gulf along the Eastern USA and normally the salty water sinks near Greenland and travels to Europe. About a year ago, I heard the current has slowed by two-thirds and may have slowed even more because the convection process for current flow is no longer operating well in warming Europe.

Remember the film where the Gulf Stream stopped flowing north causing the deep freeze in New York City where the kids had to take refuge and burn books to keep warm.

I am sure Cohen knows more than I do, but perhaps he has a profit motive for his firm which provides the guessing game of seasonal forecasts for corporations by suggesting he is better than the long-term climate models scientists. I go with those keeping quiet now. I hope they speak up. I am just an informed chemist.

Jim Kawakami, Dec 27, 2010,

Climate Change Why Cooler in Europe and East Coast Fits Warming Model or Not

Judah Cohen, NY Times, Dec 25, 2010,

Dr. Judah Cohen, Director of Seasonal Forecasting, joined Atmospheric and Environmental Research, Inc. as a Staff Scientist in 1998. Prior to AER, he spent two years as a National Research Council Fellow at the NASA Goddard Institute for Space Studies after two years as a research scientist at MIT’s Parsons Laboratory. Cohen received his Ph.D. in Atmospheric Sciences from Columbia University in 1994 and has since focused on conducting numerical experiments with global climate models and advanced statistical techniques to better understand climate variability and to improve climate prediction.

In addition to his research interests, as principal scientist, Cohen directs AER’s development of seasonal forecast products for commercial clients who include some of the largest investment firms in the US. He has been interviewed on local and national television, the Wall Street Journal, Boston Globe, and Investor’s Business Daily, among others. His work is highlighted as breakthrough technology by the National Science Foundation (NSF).

Dr. Cohen has a Research Affiliate appointment in the Civil Engineering Department at Massachusetts Institute of Technology (MIT) and is a member of the American Meteorological Society (AMS) and the American Geophysical Union (AGU). He has published over two dozen articles on seasonal forecasting in their journals and others. Most recently, Dr. Cohen was appointed Associate Editor of the Journal of Climate, a peer-reviewed publication of the AMS. He continues to further his research, in addition to directing operational long range forecasting at AER. …

THE earth continues to get warmer, yet it’s feeling a lot colder outside. Over the past few weeks, subzero temperatures in Poland claimed 66 lives; snow arrived in Seattle well before the winter solstice, and fell heavily enough in Minneapolis to make the roof of the Metrodome collapse; and last week blizzards closed Europe’s busiest airports in London and Frankfurt for days, stranding holiday travelers. The snow and record cold have invaded the Eastern United States, with more bad weather predicted.

All of this cold was met with perfect comic timing by the release of a World Meteorological Organization report showing that 2010 will probably be among the three warmest years on record, and 2001 through 2010 the warmest decade on record.

How can we reconcile this? The not-so-obvious short answer is that the overall warming of the atmosphere is actually creating cold-weather extremes. Last winter, too, was exceptionally snowy and cold across the Eastern United States and Eurasia, as were seven of the previous nine winters.

For a more detailed explanation, we must turn our attention to the snow in Siberia.

Annual cycles like El NiƱo/Southern Oscillation, solar variability and global ocean currents cannot account for recent winter cooling. And though it is well documented that the earth’s frozen areas are in retreat, evidence of thinning Arctic sea ice does not explain why the world’s major cities are having colder winters.

But one phenomenon that may be significant is the way in which seasonal snow cover has continued to increase even as other frozen areas are shrinking. In the past two decades, snow cover has expanded across the high latitudes of the Northern Hemisphere, especially in Siberia, just north of a series of exceptionally high mountain ranges, including the Himalayas, the Tien Shan and the Altai.

The high topography of Asia influences the atmosphere in profound ways. The jet stream, a river of fast-flowing air five to seven miles above sea level, bends around Asia’s mountains in a wavelike pattern, much as water in a stream flows around a rock or boulder. The energy from these atmospheric waves, like the energy from a sound wave, propagates both horizontally and vertically.

As global temperatures have warmed and as Arctic sea ice has melted over the past two and a half decades, more moisture has become available to fall as snow over the continents. So the snow cover across Siberia in the fall has steadily increased.

The sun’s energy reflects off the bright white snow and escapes back out to space. As a result, the temperature cools. When snow cover is more abundant in Siberia, it creates an unusually large dome of cold air next to the mountains, and this amplifies the standing waves in the atmosphere, just as a bigger rock in a stream increases the size of the waves of water flowing by.

The increased wave energy in the air spreads both horizontally, around the Northern Hemisphere, and vertically, up into the stratosphere and down toward the earth’s surface. In response, the jet stream, instead of flowing predominantly west to east as usual, meanders more north and south. In winter, this change in flow sends warm air north from the subtropical oceans into Alaska and Greenland, but it also pushes cold air south from the Arctic on the east side of the Rockies. Meanwhile, across Eurasia, cold air from Siberia spills south into East Asia and even southwestward into Europe.

That is why the Eastern United States, Northern Europe and East Asia have experienced extraordinarily snowy and cold winters since the turn of this century. Most forecasts have failed to predict these colder winters, however, because the primary drivers in their models are the oceans, which have been warming even as winters have grown chillier. They have ignored the snow in Siberia.

Last week, the British government asked its chief science adviser for an explanation. My advice to him is to look to the east.

It’s all a snow job by nature. The reality is, we’re freezing not in spite of climate change but because of it. Judah Cohen is the director of seasonal forecasting at an atmospheric and environmental research firm.

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