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The recent weather in the U.S. was "Siberian Express", not polar vortex.
and...
It was both.
"Bruce Sullivan, a senior meteorologist with the NWS, confirmed that the US had indeed been hit in one week by both the polar vortex – a pocket of very cold air that usually swirls around the North Pole and which made headlines when it hit the country last year – and the Siberian Express."
Quote:
Originally Posted by Ultor
From Barnes 2013: We conclude that the mechanism put forth by previous studies [e.g., Francis and Vavrus,2012; Liu et al.,2012], that amplified polar warming has led to the increased occurrence of slow-moving weather patterns and blocking episodes, appears unsupported by the observations.
Most of Barnes paper actually supports the Francis and Vavrus paper (FV12). Here's what Dr Francis says in rebuttal to Barne's 'conclusion':
"Because AA has emerged from the noise of natural variability only in the last 15 year or so, it is not surprising that its influence would not drive 30-year trends in a statistically significant way. Note that her new method does exhibit significant trends. This supports FV12."
"While FV12 did not present wave speeds, we speculated that larger amplitude waves should have slower wave speeds. Her measure of phase speed for waves at 500 hPa slows with time, supporting our speculation. She then measures speeds at the 250 hPa level and finds no change in speed. This much higher level is near the tropopause, often above the jet stream, and can be affected by dynamics of the stratosphere. The stratosphere is cooling with increasing greenhouse gases, leading to very different dynamical changes. Why did she choose to analyze this level?"
V. Petoukhov, S. Rahmstorf, S. Petri, and H.J. Schellnhuber, "Quasiresonant amplification of planetary waves and recent Northern Hemisphere weather extremes", Proceedings of the National Academy of Sciences, vol. 110, pp. 5336-5341, 2013. http://dx.doi.org/10.1073/pnas.1222000110
J.A. Screen, and I. Simmonds, "Amplified mid-latitude planetary waves favour particular regional weather extremes", Nature Climate change, vol. 4, pp. 704-709, 2014. http://dx.doi.org/10.1038/NCLIMATE2271
A small error in underlying assumptions can lead to a large error in results. I tend to agree with the AGW crowd that man caused global warming is happening although what we should do about it is an open question.
Do you realise that this adds to the already existing evidence that clouds produce a net positive warming effect and that positive feedback amplification from clouds could be slightly underestimated in climate models?
Here is another recent paper published in Nature last year supporting this:
Climate science 'skeptics' like Roy Spencer and Richard Lindzen continue to claim that clouds produce a net negative (cooling) feedback despite the fact that the evidence has already shown them to be wrong. The evidence against this 'skeptic' claim has been stacking up for some time now.
"Bruce Sullivan, a senior meteorologist with the NWS, confirmed that the US had indeed been hit in one week by both the polar vortex – a pocket of very cold air that usually swirls around the North Pole and which made headlines when it hit the country last year – and the Siberian Express."
This quote seems suspect. The NWS instructed forecasters last July to stop using the term:
Weather Service walks away from polar vortex claim (but not chilly forecast)
A DEEP UPPER LOW… NOT THE POLAR VORTEX AS ITS ORIGINS ARE FROM THE NE PACIFIC… WILL SWING THROUGH THE GREAT LAKES EARLY NEXT WEEK WITH AN IMPRESSIVE COLD SHOT OF AIR INTO THE CENTRAL AND THEN SOUTHERN PLAINS AND THE MIDWEST. A memo was emailed from the NWS’ Central Region to local offices directing forecasters to cease use of the term according to Chris Vaccaro, director of NWS public affairs. “Internally, WFOs [Weather Forecast Offices] that used the term polar vortex were gently reminded that with the term “polar vortex” comes a range of definitions and perceived impacts (however temperatures won’t be any where near the low temperatures experienced over the winter, nor would there be snow) which can distort the primary message of actual impacts that the public needs to know,” Vaccaro said in an email.
A: The phrase took on a life of its own last year, and it was blamed for everything from ice storms to the inability of the New York Giants to score touchdowns. But the National Weather Service is skittish about going anywhere near the phrase that starts with 'p' and ends with 'x.' “We’ve been told to go around that term,” said Musher, chuckling. But the answer is yes and no. Yes, because as Musher noted, the cold air is coming from near the North Pole. But also no, because the low-pressure system isn't going to sink into the U.S. this year, just the temperatures that precede it. Meteorologists say it's simply winter.
Quote:
Originally Posted by Ceist
Most of Barnes paper actually supports the Francis and Vavrus paper (FV12). Here's what Dr Francis says in rebuttal to Barne's 'conclusion':
"Because AA has emerged from the noise of natural variability only in the last 15 year or so, it is not surprising that its influence would not drive 30-year trends in a statistically significant way. Note that her new method does exhibit significant trends. This supports FV12."
"While FV12 did not present wave speeds, we speculated that larger amplitude waves should have slower wave speeds. Her measure of phase speed for waves at 500 hPa slows with time, supporting our speculation. She then measures speeds at the 250 hPa level and finds no change in speed. This much higher level is near the tropopause, often above the jet stream, and can be affected by dynamics of the stratosphere. The stratosphere is cooling with increasing greenhouse gases, leading to very different dynamical changes. Why did she choose to analyze this level?"
V. Petoukhov, S. Rahmstorf, S. Petri, and H.J. Schellnhuber, "Quasiresonant amplification of planetary waves and recent Northern Hemisphere weather extremes", Proceedings of the National Academy of Sciences, vol. 110, pp. 5336-5341, 2013. http://dx.doi.org/10.1073/pnas.1222000110
J.A. Screen, and I. Simmonds, "Amplified mid-latitude planetary waves favour particular regional weather extremes", Nature Climate change, vol. 4, pp. 704-709, 2014. http://dx.doi.org/10.1038/NCLIMATE2271
Sorry, crying to the Capital Weather Gang at WaPo that someone broke your hypothesis is not a rebuttal.
What progressing ice age? Do you think it's a good idea no matter how many people and animals it kills? How Heat Kills : Discovery News
An estimated 70,000 people died when parts of Europe boiled in the summer of 2003, according to a history of that heat wave being compiled by Richard Keller, a professor at the University of Wisconsin-Madison. In contrast, the death toll from 2005's Hurricane Katrina, which ravaged New Orleans and the Gulf Coast, was 1,836. Why Heat Waves Can Mean High Death Tolls
Choke me with a broom stick. Anyone can estimate anything. Post fail.
Ok, Stronger storms are different then the past. They happen to be part of an extreme change in weather patterns which are occuring. Warmer Temps. are part of the cause. That HS physics class some 40 years ago showed that warmer temps created changes.
Sorry, you have to give me numbers. In tabular form, if available. Oh, and define "stronger storms" IE lets see something vaguely representing scientific rigor, rather than personal anecdotal observations.
I am pretty sure we have had threads asking where all the hurricanes are. I am pretty sure we have threads here asking where all the tornadoes are. Why? because the numbers of both are WAY down since 2005!
For the last couple three winters, there has been a high pressure ridge sitting off the west coast, deflecting our storms north, into the jet stream some call the polar vortex. Those storms hit the east and the midwest as arctic events after having been chilled by arctic cold.
Good Lord... I can't believe we are still debating this. Over 99% of the Worlds climate scientists are telling us it's happening. The ONLY scientists that are saying otherwise work for oil companies.
Actually, you have it backwards. Over 99% of the worlds climate scientists are telling us AGW is a hoax.
That's true. And some of the older scientists who denied for the tobacco companies that smoking cigarettes causes lung cancer are now denying global warming. And they have little or no education or specialty in climate science.
And some of the scientists who supported the Piltdown Man hoax are now supporting the AGW hoax. They have no education in anything.
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