More of the “extreme events” meme…
From the AGU weekly highlights
Regional models expect drier, stormier western United States
Key Points
- Statistically significant increases in western US future extreme winter precipitation
- Eight dynamically downscaled GCM simulations show generalized agreement
- Spatial pattern of changes in mean precip. is different than that of extremes
As American southwestern states struggle against ongoing drought, and the Northwest braces for a projected shift from a snow- to a rain-dominated hydrological system, climate researchers strive to provide precipitation projections that are fine grained enough to be of value to municipal water managers. Estimates derived from large general circulation models show that in a warming world, water availability in the western United States will be increasingly dictated by extreme events.
However, such large models tend to lack necessary detail for the small-scale interactions and topographic influences that dominate daily changes in local precipitation. To convert the broad predictions of global models into practical predictions, Dominguez et al. used an ensemble of regional models, set to fit within the projections of general circulation models, to estimate future winter average and extreme precipitation for the western United States.
The authors find that for the years 2038–2070, winter average precipitation in the southwestern states would be 7.5 percent below 1979–1999 levels. They also find, for the entire areal-averaged western United States, a 12.6 percent increase in the magnitude of 20-year-return-period winter storms and a 14.4 percent increase for 50-year winter storms. In some regions, like southern California and northwestern Arizona, this increase in strength of 50-year storms was pushed as high as 50 percent. Though the temporal and spatial granularity of the regional climate models is much improved over that of general circulation models, workable and useful measurements for hydrological engineering and water management design will need ever-better estimates of future rainfall patterns.
Source:
Geophysical Research Letters, doi:10.1029/2011GL0507624, 2012
Title:
“Changes in winter precipitation extremes for the western United States under a warmer climate as simulated by regional climate models ”
Authors:
- F. Dominguez, E. Rivera, and C. L. Castro
- Department of Atmospheric Sciences, University of Arizona, Tucson, Arizona, USA;
- D. P. Lettenmaier
- Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA.
Abstract:
We find a consistent and statistically significant increase in the intensity of future extreme winter precipitation events over the western United States, as simulated by an ensemble of regional climate models (RCMs) driven by IPCC AR4 global climate models (GCMs). All eight simulations analyzed in this work consistently show an increase in the intensity of extreme winter precipitation with the multi-model mean projecting an area-averaged 12.6% increase in 20-year return period and 14.4% increase in 50-year return period daily precipitation. In contrast with extreme precipitation, the multi-model ensemble shows a decrease in mean winter precipitation of approximately 7.5% in the southwestern US, while the interior west shows less statistically robust increases.
Sounds familiar. The UK Wet Office has similar regional forecasts. Some areas will have more rain, some areas will have less rain. Some areas will have more drought, some areas will have less drought. Some areas will have more storms, some areas will have less storms. AND on & on it goes, HIWTYL! 🙂
As usual the modelers depend upon the models instead of emperical research. Several researchers such as Tsonis, McCabe and Betancourt have shown that drought in the American West is closely tied to the AMO and PDO. Also tree ring research in the Southwest shows that during the Medieval Warm period, the climate was wetter but during the cooler times of around 1150 and after 1300, increasing drought was a factor in the movements of the Anasazi from their ccenters like Chaco Canyon and Mesa Verde. The models assume a homeogenous response to changes in global temperatures in the West instead of the complex Dance between monsoonal flow, PDO, AMO and sunspot activity that is shown in the real world record of the past.
Models that can’t get the big things right, are now being fine tuned so that they won’t get the small things right either.
I’ll report in with my assessment of this paper in 2050.
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Meanwhile, the PDO folks have nailed the weather for this spring in the Great State of Washington – cool with more precip – both liquid and solid. And I’m getting tired of it.
I mean honestly, how arrogantly delusional do you have to be to think you can predict regional rain patterns in the years 2038–2070??? The mind simply boggles at this.
It appears that they have made at least two mistakes in their analysis, which calls into question their conclusions. First, they are spatially “improving” faulty models. Second, they are using normal statistics in their analysis of extremes. Extreme values have an extreme value distribution: not a normal distribution. Twenty and fifty year cycles are too short to properly establish probabilities and statistical significance on extreme values.
Before taking seriously regional models, go to Roger Pielke Sr’s website and read what he has on regional models. His website is on the right sidebar under “lukewarmers.”
“this increase in strength of 50-year storms was pushed as high as 50 percent”.
This is in the period after 2038, compared to the 1979-1999 period.
SInce were 40% of the way from that earlier period to the forecast period, I assume this means that we must already be seeing a significant increase in storm strengths, surely at least 15-20% by now.
So where are they?
Analog years and decades beat the hell out of models in forecasting, hindcasting and probably even bait casting. This is well known by climate scientists. That they don’t include this “control” group in their “tomes” (and I say that disparagingly because that is what research articles have become), speaks to the bias they bring to their efforts. Bad form. Very bad form.
These people are predicting drought in a desert. How … impressive.
I expect these to have the same stunning degree of success as the predictions of drought in Queensland.
How did that turn out, again?
IPCC+AR4+GCM=GIGO
Humm, wouldn’t that make them 17.48-year and 42.8-year storms, then? (extraneous significant digits left in for humourous purposes)
If the GCMs say the west will be dry, we better buy flood insurance in SoCal. Maybe I should buy a boat.
The modellers are like kids in the arcade with their video games. They sit there and play with the controls that manipulate images on a screen. And they imagine they are dealing with some kind of reality. But they really have no understanding of reality and what it will bring in the future.
Problem – Lack of monies
Four Step Solution:
1) Define a ‘potential crisis’
2) Market the ‘potential crisis’ into a “real crisis”
3) Propose “the only solution to the ‘real crisis’ ”
4) Get funding for ‘the solution’ from the “Political Intelligentsia”
Solution – more monies [problem solved].
Useful technique for the following:
1) Climate Research
2) Solar CMEs
3) Oil
4) Not enough Nukes; Too many Nukes.
5) Endangered Species; Species too be endangered.
6) Not enough Slaves; too many Slaves.
7) Works everywhere on anything – promote FEAR.
lol, droughtflood is striking again! Undoubtedly due to the warmcold.
The desperation in these dire proclamations are becoming palpable.
In the paraphrased words of the fictional Dr. McCoy……. “it’s worse than dead….. it’s brain is gone.”
These projections have been made for the years 2038–2070, approximately 25 to 60 years from now; few people now living will be alive to see the the results or to care.
These projections indicate winter average precipitation in the southwestern states would be 7.5 percent below 1979–1999 levels (which included a very wet winter ENSO year). In an area where the average annual precipitation varies from ~4 in. per YEAR to 20 in. per YEAR how much difference will 7.5% less WINTER preciptation really make?
You mean the guys who cannot tell me if it will be raining or sunny 2 weeks from now, are telling me what the weather will be like in 25 years?
And I am supposed to believe them?
Really?
Really?
Really????????
The largest desal plant in the Western Hemisphere is coming online this year in Carlsbad, CA. The solution is drought proof.
Maybe the dopes in Northern CA will catch a clue?
If I live right in the middle of the drier and stormier parts does that mean my climate is just right?
I have just started to wade through the EPA type proposed regs in the USA Federal Register with comments closing today. link ~ http://www.regulations.gov/#!searchResults;cs=0;dct=N%252BFR%252BPR;rpp=25;po=25 I just glanced at a couple and suggest a thorough reading then commenting as appropriate.
While doing so I came across something about Changes in Hydric Soils Database Selection Criteria When it comes to the US bureaucracies I have a really suspicious mind. We already know that “evidence” can be “manufactured” by changing data sets or criteria. Given what has been done to the Temperature Data base I am a bit suspicious especially given the above paper. Changing the collection of “Wet Soil” data could be really useful if you want to show evidence of shifts to “drier stormier” weather. Remember the new re-branding is ‘global weirding’
Hydric Soils ~ USDA definition
Here is the suggested changes. Perhaps one of the geologists can comment on whether the changes are a useful political propaganda weapon.
The statement “These changes do not cause any hydric soils to be added or deleted from the list.” Just does not make sense in the context of the beginning of the summary, “has updated the criteria to select map units components “
….I guess
If you throw enough predictions out there….people are more inclined to remember the ones you got right
Ric Werme says:
I can buy the southwest’s attention to the possibility of a long period of drought, but I haven’t heard much from the northwest’s bracing.
Two lousy winters in a row and a ‘year without summer’ kind of changed the mood from ‘oh no global warming’ to ‘global warming…how I so miss you’.
So regardless of the outcome, they can take credit for it. Pretty shifty devils, if you ask me.
The west has been cooling since the mid 1980s.
http://sunshinehours.wordpress.com/2012/03/22/westcoast-cooling-overlayed-on-google-maps/
http://sunshinehours.wordpress.com/2012/03/22/west-coast-has-been-cooling-since-1983-2/