Models say a future shift of western USA to "drier stormier"

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.

Advertisements

  Subscribe  
newest oldest most voted
Notify of
Harold Ambler

Embroidering the narrative, part 1266.
Speaking of narrative:
“And if all others accepted the lie which the Party imposed — if all records told the same tale — then the lie passed into history and became truth. ‘Who controls the past’ ran the Party slogan, ‘controls the future: who controls the present controls the past.’ ” — George Orwell, 1984

rbateman

IPCC says it all.
They might be happier if they moved to Mars or Venus, where the weather would suit them better.
Houston, this is IPCC Mars, the WeatherGrinch has landed.

Oldseadog

“Models say…. .”
‘Nuff said.

R Barker

If the IPCC AR4 GCMs do not demonstrate any skill in forecasting near term global conditions, how are any results based on these models to be of any use whatsoever?

Steve Keohane

My understanding is that the latter decades of the 20th century were unusually wet in the SW. A change to drier times would be a return to more ‘normal’ times. Unfortunately, we populated places like Colorado and New Mexico from the 70s on.

Adam Gallon

Someone correct me, if I’m wrong.
But don’t these models lack any “skill” when applied regionally?
(Not that they have any “skill” when applied globally!)

RCase

This really seems to be a “look over here” trick for the Warmists, since the models just aren’t cooperating with higher temperatures.
How sad is it to think that these guys are now most likely celebrating the occurrence of disastrous weather events.

Steve Keohane

After enlarging their ‘ensemble’ maps to a legible size, it looks like the prediction is for wetter times (blue) in most of the west, with a couple of spots drying out. WTF?

Who could care less what the climate models consistently predict? Are they any good at hindcasting the hydrological cycle of the region under analysis? If the answer is no, the next question to ask is, why does this sort of stuff get published?

Commander Bill

Maybe California can buy all those mothballed Australian sesalination plants they built in response to the dire drought predictions of yesteryear.

sean2829

Roger Pielke Sr has had some interesting history of the hydrology of the southwest. In the twelfth century there was a megadrought that lasted decades. Mother nature has tougher tricks up her sleeve than anything the models can dish out.

Martin Lewitt

So the modeled precipitation will by 7.5% below what 1977-1999 levels, the modeled precipitation for that range or the observed precipitation for those years? Because the AR4 models were about that much below the observed precipitation increases when simulating 1977-1999. So it should be no surprise they are that low in 2038-2070, unless the documented diagnostic issues have been specifically addressed.

Peter Miller

Well maybe, but that would Mann was right (I suppose it is always possible he is correct occasionally, but definitely not in regards to the MWP) and there was no MWP.
Just about every study indicates the MWP period was co-incident with higher precipitation in the US south west – more heat means more evaporation and that usually means more rainfall.
As per usual, these models ignore the historical evidence.
So bottom line: another example of grant generated BS.
Also, the usual predictions of doom and gloom take place long after most of us are in our boxes.

polistra

Hate to disappoint them on “drier”.
Century trend for California precip:
http://www.ncdc.noaa.gov/temp-and-precip/time-series/index.php?parameter=pcp&month=9&year=2011&filter=12&state=4&div=0
Looks slightly wetter, but not meaningful.
Century trend for Oregon precip:
http://www.ncdc.noaa.gov/temp-and-precip/time-series/index.php?parameter=pcp&month=9&year=2011&filter=12&state=35&div=0
Slightly wetter.
Century trend for Wash precip:
http://www.ncdc.noaa.gov/temp-and-precip/time-series/index.php?parameter=pcp&month=9&year=2011&filter=12&state=35&div=0
Unquestionably wetter.
Odd, innit? These “experts” love to use linear extrapolation when it’s obviously wrong, but when linear extrapolation actually gives a pretty clear picture, they totally ignore it and decide the trend must run against the data.
The only consistent thing about experts is that they are 100% wrong 100% of the time.

Pull My Finger

The east to switch to a colder warmier climate with drought induced wetness.

kadaka (KD Knoebel)

As American southwestern states struggle against ongoing drought…
Dam California! Dam it all to hell!

Richard111

What I know about the climate could be written on a postcard. So on a warming world the main temperature increase is at the poles thus the temperature gradient from the equator to the poles is reducing resulting in less wind and a more settled climate.
When a world cools the main cooling is at the poles with increasing temperature gradient resulting in increased wind and more extreme climate events.
What to believe?

Maybe I’m negative mood this bright, sunny morning in gorgeous New England, but this post is rubbing me the wrong way.

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,

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. There’s enough variability in annual snowfall that I think it would be hard to distract the population from other issues like population, highway congestion, the historic earthquake that could happen any time, the tsunami that would likely result, and just when is Mt. Ranier going to erupt next?

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

Hmm. I’m sort of tolerant of calling model output “data,” but I’m having trouble with the concept that comparing multiple runs produces “statistically significant” data. Ultimately it’s the algorithms expressed in the code that produce the results, and by making multiple runs to reduce the noise, what you’re left with reflects on the algorithms, not the numbers.
Ah well, being an OS software engineer, I tend to deal with deterministic code, and statistically significant performance data. Perhaps the OS folks in Redmond are a different breed. 🙂

Perhaps that’s what Joe Romm had in mind with his permanent drought in the SouthWest.
http://notalotofpeopleknowthat.wordpress.com/2012/01/07/romms-permanent-drought/

Oh, it’s not just a model, it’s a multi-model ensemble! Well, that makes all the difference…..

Crispin in Johannesburg

As the doom was gloomed long before there were models of it, is there just the faint possiblity that the models are full of confirmation biases?
As the climate is now cooling, and much more cooling is expected in the near term, can we use the modelled outputs to predict that the opposite effect, 7.5% wetter conditions in the SW, will actually be the coming experience?
What goes around come around. If the models are statistically correct, making falsifiable predictions, then Arizona can expect more rain in the years to come.
The empirical evidence contradicts the model, so some above think. No problem. We will just build a fire and hold the modellers feet to it while discussing the virtues of computational fluid dynamics.

Gail Combs

“….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….”
They lost me right there. I see a shift back towards the 1960’s and 1970’s with an INCREASE in blocking by pushing the climate zones more towards the equator. The Russian heatwave of 2010 and the All-Time Snowfall Records Fall Across Western Oregon & SW Washington are examples. If you watch the jet stream over the USA every day like I have for the last couple of decades you could have seen the change for yourself.
Ten years ago, the weather for my area (North Carolina) were what I saw coming from the west. Now we see more weather coming from the south, north or even east as the jet streams forms Rossby waves
I am just a farmer/scientist with a keen interest in the weather patterns that bring the rain to my fields. I can certainly see the shift in weather patterns as part of my daily study. Correct perdiction means the differnce in making or losing money in my business. I do not have the luxury of fudging data for the “Cause”

Tom in indy

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.
What do they show for a cooling world?

Alan D McIntire

I agree with their model, which is equivalent to saying that the PDO is going into a negative phase, and the earth as a whole will be cooling:
http://www.appinsys.com/globalwarming/PDO.htm
local effects of negative PDO:
Northwestern North American spring time snow pack and water year (October-September) stream flow Above average with negative PDO
Winter and spring time flood risk in the Pacific Northwest – above average with negative PDO.
For the Southwest:
http://www.climas.arizona.edu/sw-climate/pdo
“Decreases in winter precipitation associated with negative PDO conditions and intensified La Niña conditions could, for example, put stress on the urban water systems of the Southwest. Even moderately drier-than-normal conditions could have serious effects in some sectors. For example, CLIMAS researchers have documented that ranching operations in the Southwest are highly sensitive to climatic conditions. Forest fire management is another area crucially influenced by climatic conditions and trends.”

Dr. Bob

Having worked with AQMD and ARB, I see this as an opportunity to depopulate California and the Southwest. This is what the regulators want anyway. AQMD wants to totally eliminate NOx emissions and is willing to shut down all businesses in the SoCal area to do just that. With no commerce, there are no jobs, and with no jobs, there is no need for people, and with no people, there is no need for water and irrigation. That will reduce the burden on the Colorado Aqueduct, and more water will flow south. Back to Nature. When do we start? OOOOps, forgot about tinsel town. They will need their own supply of water and weather modification programs to make sure they live in luxury while the region is transformed into the Green Paradise that they always wanted it to be.

Alan the Brit

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! 🙂

Suzanne

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.

MarkW

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.

John F. Hultquist

I’ll report in with my assessment of this paper in 2050.
———————-
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.

Theo Goodwin

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.”

steveta_uk

“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?

Pamela Gray

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.

John W.

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?

atlstnspc

IPCC+AR4+GCM=GIGO

Stark Dickflüssig

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.

Humm, wouldn’t that make them 17.48-year and 42.8-year storms, then? (extraneous significant digits left in for humourous purposes)

David Corcoran

If the GCMs say the west will be dry, we better buy flood insurance in SoCal. Maybe I should buy a boat.

theduke

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.

jlurtz

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.”

Taphonomic

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?

Ferd

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????????

John from CA

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?

DavidA

If I live right in the middle of the drier and stormier parts does that mean my climate is just right?

Gail Combs

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

Hydric Soils – Definition
The definition of a hydric soil is a soil that formed under conditions of saturation, flooding or ponding long enough during the growing season to develop anaerobic conditions in the upper part.

Here is the suggested changes. Perhaps one of the geologists can comment on whether the changes are a useful political propaganda weapon.

Changes in Hydric Soils Database Selection Criteria
AGENCY: Natural Resources Conservation Service (NRCS), United States
Department of Agriculture.
ACTION: Notice of Changes to the National Soil Information System (NASIS) Database Selection Criteria for Hydric Soils of the United States.
———————————————————————–
SUMMARY: The National Technical Committee for Hydric Soils (NTCHS) has updated the criteria to select map units components for the hydric soils list. The former database selection criteria created to select soils that may meet the definition of hydric soils did not cover the full extent of what is included in the hydric soils definition. As required by 7 CFR section 12.31, NRCS is hereby providing notice of the changes to the selection criteria for hydric soils as set forth in the NTCHS publication “Hydric Soils of the United States,” miscellaneous Publication 1491, U.S. Department of Agriculture, Soil Conservation Service, June 1991 (see also 60 FR 10349). These changes do not cause any hydric soils to be added or deleted from the list.
DATES: Submit comments on or before March 30, 2012.
http://www.regulations.gov/#!documentDetail;D=NRCS-2011-0026-0001

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 “

Latitude

….I guess
If you throw enough predictions out there….people are more inclined to remember the ones you got right

harrywr2

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’.

RockyRoad

So regardless of the outcome, they can take credit for it. Pretty shifty devils, if you ask me.