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Cold Weather in Denver: Climate Change and Arctic Oscillation (8)

By: Dr. Ricky Rood , 6:25 AM GMT on December 08, 2013

Cold Weather in Denver: Climate Change and Arctic Oscillation (8)

I’ve been living with this cold weather in Colorado this week. If you look around at the Wunderground personal weather station sites, we’ve seen a lot of about -10 F at nights. It’s been causing a lot of grief for homeless people, animals and pipes. There have been a few record lows set. The whole Arctic air mass is starting to move east, which means it will get a lot more press. According to Jeff Master’s blog 80% of the country will be below average.

I thought I had finished my series of blogs on the Arctic Oscillation a couple of weeks ago, but this cold air out break takes me back. It that series I wrote about cold air in the Arctic that is isolated because of barriers caused by streams of rapidly moving air that flows around polar latitudes. I described wobbles in the streams that caused cold air to move south and warm air to move north. Here is one of the figures that I used.

Figure 1: This figure is from the point of view of someone looking down from above at the North Pole (NP). This represents a weak, wavy, wobbly vortex displaced from the pole. The vortex encloses cold air, represented as blue. The line surrounding the cold air is the jet stream or the edge of the vortex. (definition of vortex)

Figure 1 shows an idealized schematic of the North Pole as viewed from above. This is the weak vortex case, when there is a large wobble. In this case, the point X is cold and the point Y is warm. In a case of a stronger, more circular vortex, then the case would be reversed, with point X warm and point Y cold.

Here is a figure from the European Center for Medium-Range Weather Forecasts (ECMWF), that I have marked up a bit. The colors are the temperatures at the 850 hecto-Pascal surface, which is about 1.5 kilometers above the surface. The 850 hecto-Pascal temperatures are a good indicator of where it is hot and cold at the surface.

Figure 2: This figure is from the point of view of someone looking down from above at the North Pole (NP). The contour lines on the figure are the height of the 500 hecto-Pascal surface, which is between 5 and 6 kilometers above the surface of the Earth. The colors are the temperatures at the 850 hecto-Pascal surface, which is about 1.5 kilometers above the surface. The 850 hecto-Pascal temperatures are a good indicator of where it is hot and cold at the surface. Figure from the European Center for Medium-Range Weather Forecasts (ECMWF)

I drew a blue arrow showing that the cold air at the pole has wobbled off of the pole and it is pushed towards Colorado. To the west there is warm air, red arrow, pushing up towards Alaska. So while it has been cold in Colorado, it has been quite warm in much of Alaska. Though a less prominent signal, there has also been warm air moving up the East Coast of the U.S. The Alaska – Colorado contrast is a nice real-world example of what I showed in Figure 1. For completeness with my example, the big, black dashed line is the jet stream of air flowing around the pole.

There were several points in my series on the Arctic Oscillation. The first important point is that even in a world that is getting warmer, the polar latitudes become isolated as the Sun goes down for the winter and jet stream intensifies. In this isolation it gets cold, because there is no heating from the Sun and the polar latitudes have a barrier between themselves and the warmer lower latitudes. The second important point is this wobble, the pushing of air off of the pole in some direction. In this case the coldest air is over Greenland, Canada and the U.S. If there is sufficient wobble to push the air far to the south or if it gets pushed to some place it did not get pushed before, then it is even likely to have record cold. These points are all work together and are not correctly viewed as independent events. (I was recently annoyed by the parenthetical dismissal of global warming in this otherwise nice prediction of early strong lake effect snow in Michigan. The statement was essentially pockets of cold Arctic air should not exist.)

I will finish with the Arctic Oscillation. The Arctic Oscillation Index from the Climate Prediction Center is shown in Figure 3. The discussion in my Arctic Oscillation series focused on the positive and negative phases of the Arctic Oscillation Index. Much of the attention was on the eastern U.S. The negative phase was when it is likely to be very cold in the eastern U.S.

Figure 3: Arctic Oscillation Index for early August 2013 until December 7, 2013 from the Climate Prediction Center

In this measure of the Arctic Oscillation Index, the most recent times have been weakly positive, tending towards negative. (Perhaps suggesting movement of the cold air towards the U.S. east coast?) Perhaps more important Figures 2 and 3 together show that large undulations with warm air pushing far northward and cold air displaced off the pole can occur in other parts of the world when the index is weak. As pointed out many other times over the years of this blog, what goes on in the U.S. is not good instantaneous editorial content for climate change.


Previous entries:

Climate Change and the Arctic Oscillation 2

Climate Change and the Arctic Oscillation 1

Wobbles in the Barriers

Barriers in the Atmosphere


Definitions and Some Background

August Arctic Oscillation presentation

CPC Climate Glossary “The Arctic Oscillation is a pattern in which atmospheric pressure at polar and middle latitudes fluctuates between negative and positive phases.”

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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Australia in November 2013

In Brief

Averaged over the month of November, Australian maximum and minimum temperatures were both above average. The maximum temperature anomaly, +0.69 °C, and minimum temperature anomaly, +0.36 °C, combined to give a mean temperature anomaly of +0.52 °C. Maxima were above average across most of the southern half of Western Australia, in central Australia, and from western Queensland through to southeast Queensland and parts of northern New South Wales. Small areas of the tropical north, southern coastline and eastern Tasmania recorded below-average November maxima. Minima were also above average for most of the southern half of Western Australia, but warmer-than-average nights also extended into western South Australia, large parts of the Northern Territory and western and northern Queensland. Cooler-than-average nights were recorded over much of the inland southeast.
Rainfall was above the long-term average when averaged nationally (22% above average). However, above-average monthly rainfall was generally restricted to northern Australia, a narrow band along the eastern coast of the mainland and eastern Tasmania. Lighter falls through the eastern half of Western Australia also saw above-average falls recorded for November. Below-average monthly totals were recorded in scattered areas along the coast of Western Australia from Karratha to Esperance and across a broad area of the inland southeast and central Australia.

More at BOM ...
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Melting Arctic sea ice could be altering jet stream

More studies look at links to extreme weather.

The jet stream, here caught wiggling.

The rapidly warming Arctic isn’t noteworthy only for its own sake. Changes there affect the rest of the planet in a number of ways. Recently, there has been a lot of interest in whether the dwindling Arctic summer sea ice could be weirding the weather in the mid-latitudes.

There have been a number of recent summer extremes—Russia’s hellish summer in 2010, the drought in the US last summer, a very wet 2011 in Korea and Japan, plus a streak of soggy summers in the UK. There have been suggestions that lower summer sea ice in the Arctic could be gumming up the jet stream and contributing to these events, but some climate scientists aren’t so sure. A new study in Nature Climate Change brings more evidence to the table in support of the idea.

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Hydrocarbon seas spotted at Titan’s north pole


The Shape of Things to Come?
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There ya go, folks! Proof positive that 5 weeks of U.S. weather controls the climate of the entire planet.
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Global Analysis - October 2013

Global Highlights

The combined average temperature over global land and ocean surfaces for October 2013 was the seventh highest for October on record, at 0.63°C (1.13°F) above the 20th century average of 14.0°C (57.1°F).
The global land surface temperature was 0.98°C (1.76°F) above the 20th century average of 9.3°C (48.7°F)—tying with 2012 as the eighth warmest October on record. For the ocean, the October global sea surface temperature was 0.50°C (0.90°F) above the 20th century average of 15.9°C (60.6°F) and the eighth highest for October on record.

The combined global land and ocean average surface temperature for the January–October period (year-to-date) was 0.60°C (1.08°F) above the 20th century average of 14.1°C (57.4°F). The first ten months of 2013 ranked as the seventh warmest such period on record.
Member Since: December 31, 1969 Posts: Comments:
Quoting 324. tramp96:

Then you admit the models may be wrong?

Certainly, I will admit that the models may be wrong. Do you have the intellectual integrity to admit that the models may be right? Actually, do you have the intellectual integrity to admit that The Laws of Physics, Chemistry and Thermodynamics will tell us more about global warming than will your ideologically driven posts about the weather of a small region at any one time? This does more to reveal your intellectual dishonesty than it does anything else.
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Quoting 249. GTstormChaserCaleb:
This imo is a great chart, combines weather patterns, climate patterns, solar activity, volcanic activity into one. I would speculate in a warming planet that El-Nino events will become more likely. It's interesting though, that we haven't seen one in 4 years and counting. Almost as if we are overdue.

It's complicated. We'd expect that we are "overdue" for another El Nino, and some have argued that we will see them more often. Part of me wonders if it will be that straight forward. I'm not sure if we fully understand how the ocean circulations are going to respond to this rapid increase in heat energy.
You might also find this kind of app helpful:
https://sites.google.com/site/wmscottlincoln/home /other/global-temperature-contributors
I know Jim from who frequents this thread is working on a better version.

Although we have high confidence from numerous lines of evidence as to what the end result will likely be, it's much harder to say the path that weather/climate will take to get there. We'll probably learn a few more things along the way.
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People still having issues understanding the difference between precipitation and temperature. It's the same people, year upon year.
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Quoting 318. Cochise111:
This global warming is freezing the Middle East now. First time for snow in Cairo in 100 years. I guess it will only be weather until the entire world is covered with snow.

Meanwhile, look at the record warmth coming to the prairies of Canada.

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Has anyone seen the movie, The Lorax? Well if you have seen it let's try to put things into perspective, remember the guy I don't remember his name now, who went to the forest to cut down trees to make his sneads? Remember what happened when the last tree was chopped down? The forest was reduced to a wasteland and all the animals had to leave as it had become uninhabitable. The guy had a great idea, but was money hungry, and didn't think about how he would destroy the environment. Moral of this story is and how it might pertain to Global Warming is the "rise of the industrial revolution" where factories were built, trees were cut down to produce wood frame structures for houses. Take China for example, hardly a tree in site, all you see is streets and blocks of concrete buildings to the point that the pollution there is so bad that people have to where masks. Thankfully, it is not as bad here in the US., but that doesn't mean it can't become that bad, especially if industries continue with their bad habits, and aren't put under government regulations. Folks wake up and see for yourself, we, people, humans, have caused this planet to warm here in recent times, not animals, not dinosaurs, not bacteria. So all of those pointing to the planet being warmer billions of years ago, serves no purpose into what is currently going on, and it really is just a mute point not even worth debating. We need to change our ways or we will end up like the guy in the Lorax. Do you really want our future generation to suffer the consequences if we don't change our ways? I hope this can be a start to persuade the denialist views. Thanks.
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From The MetOffice(UK)

Our change in the weather and how the jet stream is driving it

After a quiet spell of weather courtesy of a slow moving area of high pressure, we are now entering an unsettled period as a series of Atlantic depressions are expected to pass close to the northwest of Britain during the next week.

High pressure has now moved away and is settled over Europe and a powerful jet stream is developing over the Atlantic which will be the main driving force behind this spell of unsettled weather.

What is the jet stream?

The jet stream is a band of fast moving westerly winds high up in the atmosphere which circle around the pole in the northern hemisphere. It can feature winds of up to 200 knots (230 mph) or more, and these winds tend to guide wet and windy weather systems which come in off the Atlantic.

The jet moves around a fair bit and its position can have a big impact on weather here in the UK depending on where it is.

If the jet is over the UK or just to the south, we tend to get a lot of wet and windy conditions as it brings weather systems straight to us. If the jet is to the north of us, it guides that changeable weather away to the north to leave the UK with more settled conditions.

What’s the jet stream doing now?

Read More ...
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Quoting 310. Astrometeor:


Let's see: 1000(# of links posted supposedly)/680(# of comments) = about 1.47 links per post. For some reason I doubt that.

Please don't make me delve into the rest of that post, my first response to that part consisted of maniacal laughter...

This was mine
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Quoting 305. yoboi:

I am posting facts.....


Quoting 305. yoboi:

I have posted over 1000 peer reviewed articles showing AGW is over-hyped....

Let's see: 1000(# of links posted supposedly)/680(# of comments) = about 1.47 links per post. For some reason I doubt that.

Please don't make me delve into the rest of that post, my first response to that part consisted of maniacal laughter...
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Quoting 305. yoboi:

I am posting facts.....I have posted over 1000 peer reviewed articles showing AGW is over-hyped....

And Weather Underground's Climate Change section isn't? They both can't be right, yoboi. One says the temperature records are accurate (WU), and the other says they are not (you).

Considering that you are unable to grasp the concept of a scientific hypothesis, data collection, statistical testing, or critical analysis, I think it can best be summarized as this:

You cannot be trusted when you post "facts".
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Quoting 291. yoboi:

FWIW the current blog topic is this....Categories: Climate Change Extreme Weather.....Extreme weather is part of the topic.....
Oh dear - I think you forgot to read the title of the blog entry at the beginning of this discussion:

"Cold Weather in Denver: Climate Change and Arctic Oscillation"

Or perhaps you simply enjoy purposely ignoring and avoiding the purpose of this blog.

Scott made no attempt to explore that possibility - he simply posted about extreme cold weather, which is a technique taught by the climate denialist industry to plant doubt and confusion about AGW/CC among ignorant and/or naive people.

"It's very cold somewhere, and even some cold records are being set - therefore AGW/CC is not happening."

Notice that he is unable to respond to my comments, and then attempts to squash the discussion and justify his posting by saying that he is simply replying to Scott Lincoln - and suggests that I'm angry, when I'm simply curious about his use of classical AGW/CC denialist tactics.
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294. Daisyworld
4:13 AM GMT on December 13, 2013
Quoting 241. yoboi:

Any temperature record that uses corrupted data is highly suspect, no matter how much the climate scientists process the raw data on their computers after the fact. (Did you know that they are still changing the temperature record for the 1970s, 30 years later, and always in the direction of making recent warming seem worse?)

But the climate scientists usually only present to the public the land thermometer records that include the corrupt land thermometers—and not even the raw data, but the data after they have very extensively adjusted and processed it. On the other hand, the satellites circle the earth 24/7, measuring the air temperature above broad swathes of land and ocean, covering all of the globe except near the poles, and are unbiased. Satellite measurements started in 1979; early problems with calibration have long since been resolved to everyone’s satisfaction.

I see you still haven't stopped posting fraudulent lies, yoboi. You completely disagree with what Weather Underground has posted on it's own Climate Change page, so one wonders why you even bother holding a user account at a website that you are so fervently against? Could it be that you simply enjoy spreading lies and disinformation? Perhaps enjoy the negative attention you garner because no one else will listen to you? To show everyone how badly the person you are quoting is lying, I re-post Weather Underground's explanation global temperature records and the heat island effect:


Science says: Independent studies using different software, different methods, and different data sets yield very similar results. The increase in temperatures since 1975 is a consistent feature of all reconstructions. This increase cannot be explained as an artifact of the adjustment process, the decrease in station numbers, or other non-climatological factors.

The goal of improving temperature data is something we can all agree on and on this point, the efforts of Anthony Watts and Steve McIntyre are laudable. However, their presupposition that improving temperature records will remove or significantly lower the global warming trend is erroneous.

Adjusting for urban heat island effect

When compiling temperature records, NASA's GISS goes to great pains to remove any possible influence from urban heat island effect. They compare urban long-term trends to nearby rural trends. They then adjust the urban trend so it matches the rural trend. The process is described in detail on the NASA website (Hansen 2001).

They found in most cases, urban warming was small and fell within uncertainty ranges. Surprisingly, 42% of city trends are cooler relative to their country surroundings as weather stations are often sited in cool islands (a park within the city). The point is they're aware of UHI and rigorously adjust for it when analyzing temperature records. (More on the urban heat island effect.)

Climate Audit and NASA's "Y2K" glitch

Steve McIntyre's discovery of a glitch in the GISS temperature data is an impressive achievement. Make no mistake, it's an embarrassing error on the part of NASA. But what is the significance?

Figure 1 compares the global temperature trend from before and after adjustments. Before the error was discovered, the trend was 0.185°C per decade. After corrections were made, the trend was still 0.185°C/decade. The change to the global mean was less than one thousandth of a degree. (More on NASA's Y2K glitch.)

Figure 1.Global temperature anomaly before (red squares) and after (black diamonds) NASA's "Y2K" corrections (Open Mind).

Other lines of evidence for rising temperatures

The surface temperature trends are also confirmed from multiple, independent sources:


So, yoboi, since you don't even agree with the owner of this blog, nor the private company which has graciously provided you with the opportunity to have an account here, you're doing nothing but insulting your benefactors by continuously posting lies.
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290. Xulonn
4:08 AM GMT on December 13, 2013
Quoting 273. StormTrackerScott:

Total moronic post as I was just replying back to Scott and it had nothing to do with GW. I just posting about the upcoming Arctic Blast. Wow some on here really need to take a chill pill.
Scott, as a person who is fascinated by the psychology of climate denialism, I'm curious why you would come to a blog created for the purpose of discussing the science of global warming and related climate change, and post weather information that is only marginally relevant, and not at all significant with respect to AGW/CC.

As a parent with a full-time job, why is it so important for you to spend your time here indirectly supporting climate denialism rather than sticking with your area of primary interest, which is weather forecasting and hyping severe weather of all types?

You are aware that this is a CLIMATE CHANGE BLOG, are you not? What aspect of climate change are you trying to tell us about?
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Dr. Ricky Rood's Climate Change Blog

About RickyRood

I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.

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