Drier, warmer springs in US Southwest stem from human-caused changes in winds
August 19, 2008
The late-winter/early-spring storm activity in the western US has shifted north since the late 1970s. This graphic shows how the peak winter storm tracks have shifted poleward since 1978. The blue line shows the storm track for February, March and April of 1978. The red line shows the track for the same months during the year 1997. Credit: Stephanie McAfee, the University of Arizona, 2008.
Human-driven changes in the westerly winds are bringing hotter and drier springs to the American Southwest, according to new research from The University of Arizona in Tucson.
Since the 1970s the winter storm track in the western U.S. has been shifting north, particularly in the late winter. As a result, fewer winter storms bring rain and snow to Southern California, Arizona, Nevada, Utah, western Colorado and western New Mexico.
"We used to have this season from October to April where we had a chance for a storm," said Stephanie A. McAfee. "Now it's from October to March."
The finding is the first to link the poleward movement of the westerly winds to the changes observed in the West's winter storm pattern. The change in the westerlies is driven by the atmospheric effects of global warming and the ozone hole combined.
"When you pull the storm track north, it takes the storms with it," said McAfee, a doctoral candidate in the UA's department of geosciences.
"During the period it's raining less, it also tends to be warmer than it used to be," McAfee said. "We're starting to see the impacts of climate change in the late winter and early spring, particularly in the Southwest. It's a season-specific kind of drought."
Having drier, warmer conditions occur earlier in the year will affect snowpack, hydrological processes and water resources, McAfee said.
Other researchers, including the UA's Laboratory of Tree-Ring Research Director Tom Swetnam, have linked warmer, drier springs to more and larger forest fires.
McAfee's co-author Joellen L. Russell said, "We're used to thinking about climate change as happening sometime in the future to someone else, but this is right here and affects us now. The future is here."
McAfee and Russell, a UA assistant professor of geosciences, will publish their paper, Northern Annular Mode Impact on Spring Climate in the Western United States, in Geophysical Research Letters, a journal of the American Geophysical Union. The National Oceanic and Atmospheric Administration funded the research via the Climate Assessment for the Southwest program at the UA.
Atmospheric scientists have documented that the westerly winds, or storm track, have been shifting poleward for several decades. The southwestern U.S. has experienced less winter precipitation during the same period.
Computer models of future climate and atmospheric conditions suggest the storm track will continue to move north and that precipitation will continue to decrease in the southwestern U.S.
The timing of the change from wet, cool winter weather to the warmer dry season is important for many ecological processes in the arid Southwest. Therefore, McAfee wanted to know how the shift in the storm track affected precipitation during the transition from winter to spring.
For the period 1978 to 1998, the researchers compared the month-to-month position of the winter storm track, temperature and precipitation records from the western U.S., and pressure at different levels in the atmosphere.
The team used a statistical method called Monte Carlo simulations to test whether the coincidence of storm track and weather patterns had occurred by chance.
Russell said the results of the simulation showed, "It's very rare that you get this distribution by chance." Therefore, she said, the changes in late winter precipitation in the West from 1978 to 1998 are related to the changes in the storm track path for that same time period.
McAfee said her next step is investigating whether western vegetation has changed as the storm track has changed.
Source: University of Arizona
Feb 08, 2010
That is not possible because a computer model says so, and computer models know all! ALL I SAID!
Man they're throwing grant money at anyone who wants to push the human based global warming agenda.
Why are all the computer "models" for weather systems both calibrated and interpreted by CHICKEN LITTLE ???
STOP GIVING THESE CLIMATE PSYCHICS MONEY.
And agg it's; "psychotics" not "psychics"
He's right, we need to be as biased as possible so that all our so called "science" can be predetermined, that way we can sit back and watch the grant money roll in.
Let them rave on....
As you all said, jet streams DO and ALWAYS WILL change. I am sick of this media hype!
1) Exactly HOW rare is this weather pattern?
2) How much energy is required to shift the westerly winds from where they were to where they are?
I suspect the answers to those questions are "Ummmmm...." and "More energy than humans produce in a year".
*snicker*
But then, it is useless to arue with closed minds.
WTF? Maybe irrelevant if you are God (as these dorks seem to think they are), but on EARTH where PEOPLE live, what PEOPLE believe is absolutely RELEVANT. If I bought what these wackos are selling, then I would vote for the most massive tax increase in history (aka "cap and trade"), but since I don't believe them, I will fight against the tax grab in order to keep my own money. Sounds pretty relevant to me... To the tune of trillions of dollars of our money.
The IPCC "Scientists" didn't prove anything. They did a (IMHO) limited review of published (and unpublished) papers. There are a large number of well documented problems with the IPCC:
1) Reviewing unpublished papers was a violation of their own rules.
2) Ignoring the responses (what few there were) of their reviewers was a violation of scientific ethics.
3) Writing their executive summaries prior to the production of the various chapters was out and out fraud since there was no way the authors were going to let those chapters contradict the summaries.
4) Averaging the output of multiple computer models, that don't produce identical results, and passing that off as proof of anything is a joke.
5) Allowing people with conflicts of interest to remain unidentified among the authors (as long as it was in a specific direction) is disingenuous.
6) Pretending that all of the reviewers looked at all of the report (instead of the low percentage that did) and that they all agreed is fraudulent.
The simple fact is the IPCC isn't a scientific body and never has been. IMHO, it's purely political and is being used to drive political changes.
You do realize that multiple astrophysicists have written papers about climate change stemming from the dramatic increase in solar energy over the past 70 years, but none of their papers are ever considered by climatologists based on the "LOL ASTROPHYSICS" attitude that climatologists have taken in regard to changes in ambient energy in the environment.
The climatic cycle and global warming perceived by climatologists match the exact increase in what physicists are seeing from solar energy output scales.
Summary: When the sun gets hotter, the Earth gets hotter. Proven by 3 things
1) Mean temperature increases recorded on Earth have increased at the same rate as recorded mean temperature increases on other planets in the solar system.
2) Human greenhouse gas (big misnomer) contribution totals less than 1/3 of a percent and never include calculations for water vapor (the real temperature change induction mechanism of the planet).
3) Solar energy output matches perceived climate change and has as been modeled back to pre-cambrian times.
It's pretty simple, when you remove the politics and theories and look at the hard data, articles like the above are intellectual mistreatment.