Jet stream moved northwards 270 miles in 22 years; climate change to blame?

By: Dr. Jeff Masters , 4:11 PM GMT on June 05, 2008

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Climate change is forcing the jet stream higher and closer to the pole in both the Northern and Southern Hemisphere, according research published this April in the journal Geophysical Research Letters. In their paper, "Historical trends in the jet streams", researchers Cristina Archer and Ken Caldeira of Stanford's Carnegie Institution of Washington analyzed data from 1979-2001, and found that the Northern Hemisphere jet stream moved northward at approximately 125 miles per decade (270 miles during the 22-year period of the study). The jet moved higher by 5-23 meters during this period, and the wind speeds decreased by about 1 mph. Archer and Caldeira's study confirms other research showing a poleward movement of the jet stream in recent decades (Fu et al., 2006; Hu and Fu, 2007). All of these changes are consistent with the behavior of the jet stream predicted by global warming theory. For example, Lorenz and DeWeaver (2007) found poleward shifts of the jet stream by 2100 in the forecasts of 15 climate models used to formulate the "official" word on climate, the 2007 Intergovernmental Panel for Climate Change (IPCC) report. However, the authors were careful not to say how much of this shift in the jet stream was due to natural causes versus human-caused climate change. It is unknown if the jet stream has natural decades-long changes in its path that could account for the observed poleward shift.


Figure 1. The jet stream is located where the strongest winds at the top of the troposphere are found (35,000-45,000 feet high, 200-300 mb in pressure).

Archer and Caldeira note that "These changes in jet stream latitude, altitude, and strength have likely affected, and perhaps will continue to affect, the formation and evolution of storms in the mid-latitudes and of hurricanes in the sub-tropical regions." They don't specify what these changes might be. There is very little research that has been done suggesting how changes in the jet stream might affect hurricane formation and strength. One effect we may begin to see in coming decades is a reduction and/or delay in the number of hurricanes that recurve northward out to sea. Recurvature occurs when a hurricane begins to "feel" the westerly winds of the jet stream. As the jet stream continues to move northward and weaken as the globe warms, we can expect that hurricanes moving though the Caribbean will be less likely to recurve, resulting in more hurricane strikes in Mexico and Central America. Unfortunately, the quality of the Atlantic hurricane database for non-U.S. landfalls is not very good, and it will be several decades before we will be able to tell if the number of hurricane landfalls in Mexico and Central America is increasing due to a poleward shift in the jet stream.

References
Fu, Q., C. M. Johanson, J. M. Wallace, and T. Reichler (2006), Enhanced mid-latitude tropospheric warming in satellite measurements, Science, 312, 1179, doi:10.1126/science.1125566.

Hu, Y., and Q. Fu (2007), Observed poleward expansion of the Hadley circulation since 1979, Atmos. Chem. Phys. Disc., 7, 9367.9384.

Lorenz, D. J., and E. T. DeWeaver (2007), Tropopause height and zonal wind response to global warming in the IPCC scenario integrations, J. Geophys. Res., 112, D10119, doi:10.1029/2006JD008087.

Jeff Masters

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314. tallahasseecyclone
1:22 AM GMT on June 06, 2008
Its only free for this hurricane season. Afterwards...i think u have to buy it. Yiu can try it out since its free this hurricane season and u wont be using it much during the off-season.

not unless all of the storms are late bloomers :)
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312. tallahasseecyclone
1:20 AM GMT on June 06, 2008
OMG we need a Tropical Depression quick. too much politickin up in here.
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309. severstorm
9:17 PM EDT on June 05, 2008
well it dont matter what they say i like Lou Dodds, might get a little over topic sometimes but unafriad to say what he thinks imo
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308. fire831rescue
1:18 AM GMT on June 06, 2008
Here goes the debate on GW again... Oh, boy. Man, when I open a can of worms, it turns out to be a 55 gallon drum... LOL.
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307. Weather456
9:16 PM AST on June 05, 2008
298. tallahasseecyclone 9:09 PM AST on June 05, 2008
Is that hurricane software any good? Downloading....

All of the ones I have had up to this point have been trial versions


Its only free for this hurricane season. Afterwards...i think u have to buy it. Yiu can try it out since its free this hurricane season and u wont be using it much during the off-season.
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306. pottery
9:10 PM AST on June 05, 2008
Weather456, Post 256 Re: ITCZ
Yes I understand that, but what is beating me is the reason for that.
Why are the N/E trades dominating ? What factors drive this direction between N/E and S/E trades?
Thanks for any help here .
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305. pearlandaggie
1:16 AM GMT on June 06, 2008
i liked olbermann better when he was on ESPN...
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304. pearlandaggie
1:15 AM GMT on June 06, 2008
303. man, i hope that was a joke as indicated by your ":)" LOL
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302. STORMTTOP
1:13 AM GMT on June 06, 2008
well, looks like the Texas High is out of the way .. just as I called for a few days ago ...
301. pearlandaggie
1:12 AM GMT on June 06, 2008
hmmmmm.....

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300. Baybuddy
1:07 AM GMT on June 06, 2008
Wolf, non-partisan? puh leeze!
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298. tallahasseecyclone
1:04 AM GMT on June 06, 2008
Is that hurricane software any good? Downloading....

All of the ones I have had up to this point have been trial versions
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297. pearlandaggie
1:08 AM GMT on June 06, 2008
man, extreme, i'm not even going to try to touch that one!
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296. pearlandaggie
1:06 AM GMT on June 06, 2008
293. here ya go...

During the last 10,000 years climate has been seesawing between the North and South Atlantic Oceans. As revealed by findings presented by Quaternary scientists at Lund University, Sweden, cold periods in the north have corresponded to warmth in the south and vice verse. These results imply that Europe may face a slightly cooler future than predicted by IPCC, the Intergovernmental Panel on Climate Change.”

“…during the last 9000 years we can identify a persistent “seesaw” pattern. When the South Atlantic was warm it was cold in the North Atlantic and vice verse.”

As many know, the “great conveyor belt” of the Atlantic is major factor in Northern Hemisphere Climate. It seems to be driven by ocean salinity changes, which are the result of periodic ice freeze/melt cycles.

“This is known to have happened repeatedly during the present Interglacial (the warm period since the last Ice Age). Minor disturbances have taken place in recent time, such as the Great Salt Anomaly in the 1970s, which seriously affected the cod population around the Faroe Islands.”

This lines up well with the cooling trend seen in surface temperature data from about 1940 to the late 1970’s, when “global cooling” was a big concern for scientists. Now it appears that we are in the flip side of the salinity cycle, and ice is melting again.

This is a good illustration that scientists don’t fully understand Earth’s complex climate system and its myriad of interactions and cycles, and that there are things yet to be discovered about what drives climate.
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294. extreme236
1:04 AM GMT on June 06, 2008
Wolf tries to be as nonpartisan as possible...makes him a good reporter :-)

His show wouldn't be as good without the Jack Cafferty segment though...
Member Since: August 2, 2007 Posts: 19 Comments: 19234
293. catfuraplenty
12:53 AM GMT on June 06, 2008
Dr. Masters, very interesting article. Lots to think about. What about changes in the gulf stream due to the amounts of melting ice putting fresh water into the salt run system? Has this been looked at?

It's rather disquieting to see the wind arrows that look like they want to scoop everything into the GOM. I know it isn't like that, that there are so many steering factors, still...

Thanks again.
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292. pearlandaggie
1:01 AM GMT on June 06, 2008
291. but ol' wolfie doesn't, right? ;)
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291. extreme236
12:59 AM GMT on June 06, 2008
289.

I know but Lou Dobbs certainly gets a little crazy sometimes...can drive you crazy listening to him sometimes...
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290. weatherblog
12:58 AM GMT on June 06, 2008
What happened to this blog? It was more busy here in April...
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289. pearlandaggie
12:56 AM GMT on June 06, 2008
287. no one even mentioned Lou Dobbs except you! :)
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288. fire831rescue
12:54 AM GMT on June 06, 2008
Whew! I'm back. Had to go to the firing range to requalify for work. I passed. Anyways, sorry to stir up the GW debate earlier. I guess I just have a different view than others. I look at all sides and not just one...
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287. extreme236
12:55 AM GMT on June 06, 2008
Don't even get me started on Lou Dobbs lol
Member Since: August 2, 2007 Posts: 19 Comments: 19234
286. pearlandaggie
12:51 AM GMT on June 06, 2008
283. lost a little respect for you on that one! LOL
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285. presslord
8:51 PM EDT on June 05, 2008
...don't make me have to take up for her....
Member Since: August 13, 2007 Posts: 0 Comments: 10479
283. extreme236
12:50 AM GMT on June 06, 2008
I have to say though Presslord that I think Wolf Blitzer would have to be my favorite CNN reporter...Larry King is one of my least since he is so boring...
Member Since: August 2, 2007 Posts: 19 Comments: 19234
282. extreme236
12:49 AM GMT on June 06, 2008
281.

Yeah the blog has died out for a little bit it seems...it was boring enough to get to the point of talking about Campbell Brown on CNN lol
Member Since: August 2, 2007 Posts: 19 Comments: 19234
281. pearlandaggie
12:48 AM GMT on June 06, 2008
man, the blog just died!
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280. extreme236
12:40 AM GMT on June 06, 2008
279.

LOL...I occasionally watch her show...a good place for election news.
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279. presslord
8:37 PM EDT on June 05, 2008
lol....I have a huge crush on Campbell Brown....
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278. extreme236
12:37 AM GMT on June 06, 2008
lol presslord you and I posted the same thing at about the same time

Also they are also reporting some in Nebraska as well now.
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276. extreme236
12:33 AM GMT on June 06, 2008
CNN is reporting that a tornado is on the ground in Iowa and one in Missouri.
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275. presslord
8:33 PM EDT on June 05, 2008
CNN is reporting "multiple tornados" on the ground in Iowa and Missouri....
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274. pearlandaggie
12:29 AM GMT on June 06, 2008
262. so THAT'S why the waves offshore are 4-7 feet when they are normally 2-3 feet this time of year.

264. give me a DAYUM break! idiocy!

268. the path to hell is paved with good intentions. however, i'm not convinced the bill was presented with "good" intentions, but rather designed to line some folks' pockets. however, i'm surprised you clicked a blind link like that...i figured no one would.
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272. hahaguy
8:22 PM EDT on June 05, 2008
I'm doing pretty good StormW
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271. atmoaggie
12:18 AM GMT on June 06, 2008
They have had a couple of days of 40 mph gusts here in Tulsa...Link

Steady wind of about 25 mph almost all the time. Don't get that much wind along the gulf, usually.
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270. msphar
12:17 AM GMT on June 06, 2008
I see the ITCZ is again sagging southward. Is this normal behavior prior to its jumping north ? Someone earlier pegged the date for its traditional movement north to be Jun 24 plus or minus a week. Does this seem reasonable for this year
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268. extreme236
12:14 AM GMT on June 06, 2008
pearland-

I heard about that bill a few days ago...it had good intentions but the economy and the American people can't handle that right now. I knew it wouldn't pass.
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267. hahaguy
8:13 PM EDT on June 05, 2008
How are you doing tonight StormW
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266. extreme236
12:12 AM GMT on June 06, 2008
264.

LOL stormkat your so annoying
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264. STORMTTOP
11:59 PM GMT on June 05, 2008
the global weather is about to get very violent. To the likes of which we have never seen. Our Days Are Numbered.

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.