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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764. stormdude77
10:00 PM AST on June 06, 2008
Looks like ''big fare up'' of convection just east of Trinidad, assciated with this Twave (probadly due to the Dmax)?
762. Tazmanian
7:03 PM PDT on June 06, 2008
gas is any where from $4.45 to 4.65


hurricanes in the gulf is not welcome this year or will be looking at $6 gas or more



hi pot
Member Since: May 21, 2006 Posts: 5089 Comments: 114066
761. pottery
10:00 PM AST on June 06, 2008
Hey Dude. Quiet in the blog right now.
We look to be getting some rains, you and I, if the dry air allows this wave to hold on overnight. What is your take on the situation ?
Member Since: October 24, 2005 Posts: 0 Comments: 23080
760. stormdude77
9:58 PM AST on June 06, 2008
Good evening all
759. pottery
9:54 PM AST on June 06, 2008
/
Hi Taz. How you do ?
Member Since: October 24, 2005 Posts: 0 Comments: 23080
758. Tazmanian
6:33 PM PDT on June 06, 2008
wind shear has drop out there look in the gulf its 5 to 10kt i hop we dont get any thing in the gulf any time soon all so wind shear off the E coast is low has well 5 to 10kt all so the wind shear is the CATL has drop to 5 to 10kt if any thing where to move this a little N of it. it will run in to 40kt of wind shear but i think that will drop has well with in the next few days

Member Since: May 21, 2006 Posts: 5089 Comments: 114066
757. nrtiwlnvragn
9:35 PM EDT on June 06, 2008
753. StSimonsIslandGAGuy

SPC Storm Reports
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756. Drakoen
1:31 AM GMT on June 07, 2008
Anything that forms around the Gulf of Tehuantepec is likely to be steering WNW or NW in to Mexico under the influence of a deep layered ridge axis extending outward into the western GOM.
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755. Weather456
9:30 PM AST on June 06, 2008
754. pottery 9:30 PM AST on June 06, 2008
Thanks 456. Eagerly looking forward to that " bulf " of rain LOL


lol
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754. pottery
9:24 PM AST on June 06, 2008
Thanks 456. Eagerly looking forward to that " bulf " of rain LOL

DDR, glad to hear that. I had a "trace" half hour ago. But I do expect some decent showers late tonight, and tomorow. I long to hear the water pouring into the tanks.......
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752. Tazmanian
6:26 PM PDT on June 06, 2008
so has the big H set up shop yet???
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751. Tazmanian
6:25 PM PDT on June 06, 2008
ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
500 PM PDT FRI JUN 6 2008

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

1. AN AREA OF SHOWERS AND THUNDERSTORMS EXTENDS FROM THE GULF OF
TEHUANTEPEC SOUTHWARD FOR SEVERAL HUNDRED MILES OVER THE EASTERN
PACIFIC. THERE ARE NO SIGNS OF ORGANIZATION AND DEVELOPMENT...IF
ANY...SHOULD BE SLOW TO OCCUR.

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

Member Since: May 21, 2006 Posts: 5089 Comments: 114066
750. Drakoen
1:23 AM GMT on June 07, 2008
We'll see if the negative NAO will allowing for the ITCZ to come up as the long-range GFS run indicates. That 1030mb+ High is just increasing the pressures in the CATL and allowing the flow to extend further southward.
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749. DDR
1:22 AM GMT on June 07, 2008
Hey pottery
looks like rain tonight... its drizzling here.
Its coming from a NE direction,have you noticed that flare up of convection to the ESE
Member Since: April 27, 2007 Posts: 14 Comments: 1627
748. Weather456
9:20 PM AST on June 06, 2008
743. pottery 9:13 PM AST on June 06, 2008
Hi 456.
Your take on the wave approaching. Looks to be mostly to affect Bdos and north as far as you?
I hope for some straggling showers.!!


I believe that T&T will get some. The forecast calls for some to reach us here in the Leewards which seems reasonable as the northern part of the wave interacts with the southwesterly flow east of the upper trough over the cbbean. But the bulf of rain should remain south of us.
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746. Drakoen
1:20 AM GMT on June 07, 2008
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745. pottery
9:13 PM AST on June 06, 2008
Post 743 correction.
Maybe, looking at 8:30 sat images, I will get more than a straggler after all......
Member Since: October 24, 2005 Posts: 0 Comments: 23080
744. hurricane23
9:14 PM EDT on June 06, 2008
Wilma had near pefect conditions when it formed in 2005. I am a firm believer that monsoons play a role in tropical cyclone development.
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743. pottery
9:10 PM AST on June 06, 2008
Hi 456.
Your take on the wave approaching. Looks to be mostly to affect Bdos and north as far as you?
I hope for some straggling showers.!!
Member Since: October 24, 2005 Posts: 0 Comments: 23080
742. hurricane23
9:09 PM EDT on June 06, 2008
This moonsoon trof was around in 2005 lets hope it does not stick around for a long time.
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741. pottery
9:08 PM AST on June 06, 2008
A very good series of posts earlier on the itcz, its location and the reasons for that.
Informative and educational.

Bravo!
Member Since: October 24, 2005 Posts: 0 Comments: 23080
740. Weather456
9:05 PM AST on June 06, 2008
The upper flow that rounds the base of the upper trof across the Cbbean along with daytime heating continues to enhance vigoruous showers and thunderstorms across Central America.

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739. pottery
8:54 PM AST on June 06, 2008
Hi all. Back for a while. In Trinidad___
Currently there are occasional drizzles, calm winds, humidity at 69%, temp at 88f, time 9:00 pm
The wave approaching is losing convection rather quickly, and its passage will bring some welcomed showers through Sunday. I personally dont see any heavy rains in this.
Local forecasters are calling for 70% chance of thunderstorms Sun and Mon.
Member Since: October 24, 2005 Posts: 0 Comments: 23080
738. condesa
12:48 AM GMT on June 07, 2008
Whoa.
Thank you both, a lot, Drak and StormW-
QBO's and Climate Oscillations.
Rather breathtaking.
737. hurricane23
8:52 PM EDT on June 06, 2008
Levi32 the smoothing addition is awsome if you ask me.Great job WU.
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735. Levi32
4:48 PM AKDT on June 06, 2008
Hey sorry bit off topic, but you guys noticed this new feature on the radar? Who needs to buy those smoothing programs now lol.

Free Image Hosting at www.ImageShack.us

^Click to enlarge^
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734. Drakoen
12:44 AM GMT on June 07, 2008
733. StormW 12:44 AM GMT on June 07, 2008 Hide this comment.
Drak,

Excerpt from the following
CLIMATE OSCILLATIONS

During the hyperactive season of 1995 when 19 tropical cyclones were observed (second only to 1933's 21), the QBO was in a westerly direction.



Thanks for that StormW!
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732. hurricane23
8:36 PM EDT on June 06, 2008
The QBO switched to its west phase at the end of last winter and currently continues to strengthening in magnitude.
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730. Drakoen
12:35 AM GMT on June 07, 2008
I wonder what the QBO phase was like in 1933...
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729. TerraNova
8:32 PM EDT on June 06, 2008
715. Drakoen 8:22 PM EDT on June 06, 2008
713. StormW 8:20 PM EDT on June 06, 2008

Thanks Storm and Drak. I'll be posting my 2008 predictions (or, at least, my best attempt at predicting) on my blog later tonight or tomorrow.
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728. Drakoen
12:31 AM GMT on June 07, 2008
720. condesa 12:28 AM GMT on June 07, 2008
Drak-
I've spent an unusual amount of time thinking and reading about the ITCZ the last few days; I've been wondering about the present/future effect the retreating jetstream has or will have on it.
What do you think?



Indirect affect. The Jet stream further north allows more ridging in place and depending on the strength of the high/ridge will determine what the atmospheric pressures down by the ITCZ is like at how much force is being expanded down on it.
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727. Weather456
8:32 PM AST on June 06, 2008
724. StormW 8:31 PM AST on June 06, 2008

That was the confusing part...Easterly in 2005. Thanks
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726. HurricaneSammy
12:31 AM GMT on June 07, 2008
-----------------------------------------------
Hmmmm

Nothing Yet to watch ... Sigh ...
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725. hurricane23
8:31 PM EDT on June 06, 2008
456 the easterly phase slows formation of tropical cyclones while the westerly gives it a boost.
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723. hurricane23
8:28 PM EDT on June 06, 2008
2004 had a westerly QBO and we saw we could happen.
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722. Weather456
8:27 PM AST on June 06, 2008
713. StormW 8:20 PM AST on June 06, 2008

I've been looking at the QBO....just to be sure....westerly translates to enhance or supress Tc activity?
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721. forecastFlyer
7:28 PM CDT on June 06, 2008
SURFMOM
It's been weeks since we had any significant rain in STX. The forecast is teasing with 20% right now. When it thunders here it is startling.
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720. condesa
12:04 AM GMT on June 07, 2008
Drak-
I've spent an unusual amount of time thinking and reading about the ITCZ the last few days; I've been wondering about the present/future effect the retreating jetstream has or will have on it.
What do you think?
719. hurricane23
8:27 PM EDT on June 06, 2008
Usually the tropics are pretty slow during QBO east phases, while enhanced tropical cyclone activity is observed during QBO west phases.
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718. surfmom
12:23 AM GMT on June 07, 2008

BBL dogwalk b/4 more showers
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717. severstorm
8:25 PM EDT on June 06, 2008
all4 hows ya doing up in virginia
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716. all4hurricanes
12:16 AM GMT on June 07, 2008
Sorry I haven't posted for a while my internet was
down after the storm although it had nothing to do with the storm suspicious isn't it
well nothing to bog is happening in the tropics but I noticed a band of lower shear at about 26 degrees north

Me thinks our 2nd storm will form there
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715. Drakoen
12:21 AM GMT on June 07, 2008
I haven't been following the QBO. I think its westerly at 30mb and easterly but becoming westerly at 50mb.
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714. pearlandaggie
12:20 AM GMT on June 07, 2008
709. you can have the DAYUM surf...it's supposed to be calming down right about now as the offshore fishing season really kicks into high gear! i'm starting to resent the sight of surfboards! LOL
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About JeffMasters

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