Jet stream moved northwards 270 miles in 22 years; climate change to blame?
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
Reader Comments
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After the heating of the day over florida, that ULL should help alot of storms pop.
Action: | Ignore User
Lol....That outlook was a bit painful to read through.....Just get to the point right?....
Yeah, GM wannabe.
The only thing that stays the same: Change
Working on the boat today - but will check during "sun breaks". Don't want that ULL to sneak up on me. LOL
From local surf report-I wouldn't count on this, forget it...it's flat out there.
That aside, it's way too early to tell. Also, it only takes one storm. Hurricane Andrew didn't form until August 22nd.
You ever see one of those funnels that come down and barely spin? They look like a dipping cloud until you see a small turn...Common in Florida.
After the heating of the day over florida, that ULL should help alot of storms pop.
Agree with that. Coverage will be much greater today with decent upper level support. As soon as the sea breeze moves in it should be go time.
JP, last year many called last year a bust....those people should tell that to the people in Mexico.....no bust there.
I spect we may here from him Later today.
Saw a funnel cloud yesterday in the Ft Myers area...it did not touch down the period of time I could see it....There was very little in rotation...
1518. vortfix 2:14 PM GMT on June 09, 2008
Twister damages 53 mobile homes in Lee
7:47 a.m.
The National Weather Service is sending a representative to assess the damage in North Fort Myers caused by yesterdays tornado.
Looks like these 2 posts are contridictory. (sp?)
when you all say that hurricane season is a bust and when its olny the 1st two weeks of june
dont make hurricane season mad at you it could come back right at you for saying it was a bust
this is crazy
Me thinks it was a joke Taz.
Is it a naked swirl?
So I guess it depends on where you are on whether this season is going to be a bust or not. I hope it's a bust at my house.
Wonder How Jeff Masters Hiking went?
I spect we may here from him Later today.
Hi Pat, did he say 1 or 2 weeks?
Don't think it is all that yet. Been watching a bit of a shear zone that has been moving W for the last few days between Cuba and Jamaica.
Probably nothing-just looks "funny"
Its got a lil' "twist" to it...hehe
Bu
huh?
I know some on here use firefox...which i know little about.....but, is there anything that updates the blog without having to refresh it all the time.
Hey Tampaspin...longtime Mosaic/Netscape/Mozilla/Firefox user here, going to switch to SeaMonkey soon. But I tried this out for IE6 auto refresh and it works great (Thanks to Chippy_Minton over at the MoneySavingExpert.com Forums).
1. Copy the VB code below into Notepad.
2. Save the file to your desktop named "IErefresh.vbs" (without the quotes)
3. Double-click on the IErefresh.vbs icon to run the script. A small window will pop up and prompt for the URL. The http:// part is optional. Since we are in paged view, I think it is important to enter the URL in this form:
www.wunderground.com/blog/JeffMasters/comment.html?entrynum=958&tstamp=200806#commenttop
I think that #commenttop part at the end keeps you from getting stuck on a page.
4. Next, the program will prompt for the number of seconds for the interval of the auto-refresh. The default is 60 seconds. Be careful because if you auto-refresh while you are typing a comment you might lose your comment (not sure of what happens then).
5. The script automatically brings up IE for you and auto-refreshes. Works just fine.
6. Alternately, check out:
http://urlrefresh.harrybailey.com/
Note: The code I meant to post looked fine in the preview, and tested out, but when I posted it to the blog it got mangled. Please look ahead to post #1563 in this blog for the link to the original code that can be copied into Notepad.
1512. Buhdog 1:57 PM GMT on June 09, 2008
Saw a funnel cloud yesterday in the Ft Myers area...it did not touch down the period of time I could see it....There was very little in rotation...
1518. vortfix 2:14 PM GMT on June 09, 2008
Twister damages 53 mobile homes in Lee
7:47 a.m.
The National Weather Service is sending a representative to assess the damage in North Fort Myers caused by yesterdays tornado.
Looks like these 2 posts are contridictory. (sp?)
Wow!! I can't believe it must have already done damage to the mobile homes and gone back to funnel cloud stage...I had not seen the news yet. How do these things find Mobile parks so easily?
A little too complicated for us "older" men; I prefer to hit the refresh button so I know where I last left off when I had to take a bathroom break, which, is pretty frequently these days..........Lol
How can anyone not grasp that the guy was just joking?
Is two weeks into the future about the limit presently in predicting upper level wind patterns?
Mobile homes are tornado magnets!
the building here at work is down,can you say preventive maintenance before there is a heatwave??
You talkin' 'bout the ac?
LOL, weathermanwannabe, I'm rollin' down that second half of the century now too!
Pretty easy really, copy, paste, save, double-click...but personally I'm with you, I manually refresh...that is probably why I often end up talking to people that left 20 minutes ago, lol.
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