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Ed Hartouni

Trad climber
Livermore, CA
Dec 9, 2014 - 06:23pm PT
from the report that started the latest "discussion"

http://cpo.noaa.gov/sites/cpo/MAPP/Task%20Forces/DTF/californiadrought/california_drought_report.pdf

CAUSES AND PREDICTABILITY OF THE 2011-14 CALIFORNIA DROUGHT

Abstract


The causes and predictability of the California drought during the three consecutive rainy seasons (November-April) 2011/12 to 2013/14 are analyzed using observations and ensembles of simulations conducted with seven atmosphere models forced by observed sea surface temperatures (SSTs). Historically, dry California winters have most commonly been associated with a ridge off the west coast, part of a mid-latitude wave train having no obvious SST forcing. Wet winters have most commonly been associated with a trough off the west coast and an El Niño event. These attributes of dry and wet winters are captured by many of the models used in the current assessment. According to the models, up to a third of California winter precipitation variance can be explained in terms of SST forcing, with the majority explained by internal atmospheric variability. Nonetheless. SST-forcing was key to sustaining a ridge of high pressure over the west coast during each of the last three winters, and may have explained nearly one-third the CA precipitation deficits during the recent drought. In 2011/12 the forced component was a response to a La Niña event whereas in 2012/13 and 2013/14 it was related to a warm tropical west Pacific SST anomaly. All models contain a mode of climate variability that links west Pacific SST anomalies to a northeastward propagating wave train with a ridge off the North American west coast as part of its SST sensitivity during at least the last 35 years. This mode explains less variance than ENSO and Pacific decadal variability and its importance in 2012/13 and 2013/14 was unusual. The CMIP5 models project that rising greenhouse gases should increase California winter precipitation but that changes to date are small compared to the recent drought anomalies. As such, the recent drought was dominated by natural variability, a conclusion framed by a discussion of the differences between observed and modeled tropical SST trends over the past decades.

Interestingly, The Chief seems to be defending this report which has a substantial model input and includes a comparison to the CMIP5 runs.

How are the models considered "right" in this report, and "wrong" in others?

I'm not sure how many posting to this thread has actually read the report. Perhaps one might take that as a first step...

Bob Harrington

climber
Bishop, California
Dec 9, 2014 - 07:16pm PT
I read the Seager et al. report today. The gist of it is that the past three years of drought in California were driven by 'internal atmosphere variability' and sea surface temperature anomalies, not by human-induced greenhouse gas forcing. It looks like a well done modeling study, to the extent I understand it -- I'm no expert in this kind of modeling.

I guess we've at least reached consensus that GCM models are useful.

The linkage between SST's and California climate has been greatly exaggerated in the media. We've had very dry years during strong El Ninos (e.g. 1988) and wet years during La Nina (e.g. 2011) so the reliance on SST's to predict California precip is very tentative, as this paper acknowledges. The conclusions the paper are limited to the past three years, and don't address longer term trends in California climate. For a more general analysis of climate change effects on the southwest, see Richard Seagar's web page, where, from a 2007 publication, he concludes that the southwest US will become increasingly arid due to greenhouse gas emissions, the transition to a drier climate may already be underway, and that this is a robust climate modeling result.
Malemute

Ice climber
great white north
Dec 9, 2014 - 07:26pm PT
Take home lessons:

Southwestern North America and other subtropical regions are going to become increasingly arid as a consequence of rising greenhouse gases.
The transition to a drier climate should already be underway and will become well established in the coming years to decades, akin to permanent drought conditions.
This is a robust result in climate model projections that has its source in well represented changes in the atmospheric hydrological cycle related to both rising humidity in a warmer atmosphere and poleward shifts of atmospheric circulation features.

An imminent transition to a more arid climate in southwestern North America
Richard Seager
Lamont-Doherty Earth Observatory of Columbia University

http://www.ldeo.columbia.edu/res/div/ocp/drought/science.shtml
Ed Hartouni

Trad climber
Livermore, CA
Dec 9, 2014 - 07:32pm PT
Even a blind pig can find an acorn once in a while.

are you speaking from personal experience?
TGT

Social climber
So Cal
Dec 9, 2014 - 07:35pm PT
http://www.thepiratescove.us/2014/12/08/if-all-you-see-1337/
Ed Hartouni

Trad climber
Livermore, CA
Dec 9, 2014 - 07:47pm PT
To have explained the interrelationship amongst the climate mechanisms I mentioned this morning would have been to elaborate on the basics of a climate change theory requiring very little radiative forcing from CO2. It fits the modern climate fluctuations, as well as historical fluctuations ,...

if you have detailed models, rick show them... put them up against the "standard models..."

in fact, point us to the output files from your model(s) so we can include them in discussions... you know, like the outputs available from all the current climate models.

I'd readily put them on various plots for comparison... just show me where the outputs are...

Malemute

Ice climber
great white north
Dec 10, 2014 - 07:10am PT
The Polar Sea: An Unprecedented Look at the Northwest Passage
Narrated by Gordon Pinsent
videos at http://tvo.org/story/polar-sea-unprecedented-look-northwest-passage#watchPolarSea
'magazine' at http://www.polarsea360.com/episodes/01/
Norwegian

Trad climber
dancin on the tip of god's middle finger
Dec 10, 2014 - 07:24am PT
shut the f*#k up both of you
im the d#@&%ebag around here.
raining
Norton

Social climber
quitcherbellyachin
Dec 10, 2014 - 08:26am PT
there is really only one serious problem with personal insults

and that is that someone will report the post to ChrisMac or RJ

who both said a week ago that such posts would not be tolerated and should be reported

then one is deactivated, with no apparent warning, other than many of them through the years
k-man

Gym climber
SCruz
Topic Author's Reply - Dec 10, 2014 - 08:40am PT
I mean, who would get so butt hurt over little ouchy words to do that?


I don't post here and read this forum to get attacked or to see others get attacked. The clowns that begin the ad homs attacks should pack it up--it only brings this forum down. The consequence is that folks who have good contributions to make leave.

So what do you want, the forum to wallow down in the cesspool of insults and negative attacks, or should we attempt to clean it up.
dirtbag

climber
Dec 10, 2014 - 08:42am PT
Maybe both of you guys should do some post editing and move on.
crunch

Social climber
CO
Dec 10, 2014 - 08:53am PT
In case you don't already understand this, a "drought" is not the "norm." Here, take a look:

drought
noun
a prolonged period of abnormally low rainfall; a shortage of water resulting from this.


So what are you saying above The Chief when you state that the conditions were "THE NORM!!!!"?


Just because I stated it was the "Norm" does it no where state there is NO DROUGHT.

Are you trying to say that the "drought" is then norm, meaning there is no drought? If not, then what do you mean??

Watch out here The Chief, your credibility might be at stake!

Isn't it the case that as we learn more about what was going on hundreds and even thousands of year ago our idea of "normal" is evolving.

In particular, whatever has been considered as "normal" California climate by 20th century standards is too limited and that a real "normal" California climate includes intermittent but multi-years-long droughts?

And that the current drought is not outside of what we now understand to be California's "norm."

I thought this was NOAA's point, when it declined to blame AGW for the current drought.
k-man

Gym climber
SCruz
Topic Author's Reply - Dec 10, 2014 - 09:20am PT
Sketch is gone.
Ed Hartouni

Trad climber
Livermore, CA
Dec 10, 2014 - 09:21am PT
it is always a good thing to read the report... here are some extracts:

"Drought is of course nothing new to California. Figure 1 also shows that, despite the remarkable nature of the last year and last three years in California’s recorded history, these events are not without precedence. Figure 2 (below) shows the winter half-year precipitation history for all of California. For example the driest winter was 1976-77 and there was an extended dry period in the 1920s and 1930s (Mirchi et al. 2013), which included the second driest winter of 1923-24. The driest three-year period was 1974 to 1977, which included the driest winter and 1975-76, the fourth driest winter. There have also been extended wet periods, including one in the mid 1990s. This preceded a period of steadily declining precipitation up to and including the 2013-14 drought and part of the explanation of the recent drought will involve explaining the decline in winter precipitation over the recent two decades. However, over the entire 120 years of record, there is no clear trend towards wetter or drier conditions."

Histograms of one-year &#40;top&#41; and three-year average &#40;botto...
Histograms of one-year (top) and three-year average (bottom) winter all-California precipitation for 1895-96 to 2013-14 from NOAA Climate Division data. The last three years are marked in the top panel and the last three-year average is marked in the bott
Credit: Seager et al, 2014, "Causes and Predictability of the 2011-2014 California Drought"

Time series of all-California November to April winter precipitation f...
Time series of all-California November to April winter precipitation for1895 to 2014 and the same after low-pass filtering with a seven year running average Units are mm/day.
Credit: Seager et al, 2014, "Causes and Predictability of the 2011-2014 California Drought"

I added the emphasis to point out that the authors of the report do consider the recent drought to be "remarkable."

"The current depleted state of water supply available to municipalities and agriculture in California arose from a major, if not record-breaking, meteorological drought. Winter 2013-14 was the sixth driest winter since records began in 1895 and the three-winter average precipitation from 2011-12 to 2013-14 was the second lowest on record (behind 1974 to 1977)."

So it would seem the report considers the that there is a remarkable drought in California.

They take a crack at what might happen this year, too:

"During October 2014, the warm SST anomaly in the western tropical Pacific that contributed to the drought of the past two winters disappeared. In November 2014 there is a warm SST anomaly that extends across most of the equatorial and subtropical North Pacific. Further, as shown at the International Research Institute for Climate and Society’s website http://iridl.ldeo.columbia.edu/maproom/Global/Forecasts/, forecasts predict SST anomalies to remain weak in the western Pacific Ocean and a weak to modest El Niño pattern to develop. To go along with this models are predicting a modestly increased probability of wetter than normal conditions for northern Mexico and the southern U.S. The current (November) Climate Prediction Center forecast indicates an about 45% chance of central to southern California precipitation being in the upper tercile of the historical distribution. . However, if either current conditions persists or if the SST forecasts are correct, the localized warm anomaly in the western Pacific that contributed to California drought the past two winters will not be present this coming winter. It is therefore reasonable to assume that precipitation amounts will very likely be greater than last winter, but not necessarily much above the climatological normal. It should also be noted that even a reasonably strong El Niño event, which seems highly unlikely, does not guarantee a wet California winter. Notably two of the driest winters on record occurred during the 1976-77 and 1986-87 El Niño events!"



it should also be noted that we are debating regional climate on relatively short time forecasting, that is remarkable in its own right... and a very real demonstration of the power of recent advances in climate science.
Dingus Milktoast

Gym climber
Maestro, Ecosystem Ministry, Fatcrackistan
Dec 10, 2014 - 10:24am PT
DMT
Do you disagree with any of:
-the earth is warming.
-warmer air holds more water vapour.
-warmer air can pick up more moisture than colder air.
-warmer air can also dump more rain than colder air.
-the arctic is warming faster than the US.
-the smaller temperature differential south of the arctic enables the jet stream to form large loops.
-these loops allow weather systems to stay in one place longer than usual.
-this was the cause of the Calgary flood.

My agreement isn't the issue Malemute. I don't know enough to agree nor disagree with the conclusion. But linking a single weather event to climate change seems a perilous journey. When its wrong, like an attribution to climate change for the current California drought?

The baby gets tossed with the bathwater. I'm certainly not convinced that the science is solid enough to attribute a Calgary flood to global warming. Is that disagreement?

DMT
Malemute

Ice climber
great white north
Dec 10, 2014 - 11:15am PT
my point DMT is that weather is an oscillating line superimposed on a baseline. That baseline is essentially an average of the measured weather, be it rainfall, temperature, etc. The temperature baseline is increasing, which means the oscillations are also moving up. That is why there are more high temperature records being broken than there are low temperature records being broken.

While one cannot say the Calgary flood was solely caused by climate change, one can say that the changing climate is increasing the probability of such floods. If you want "common sense" verification, search this thread for posts concerning insurance.
Norton

Social climber
quitcherbellyachin
Dec 10, 2014 - 11:19am PT
and that is that someone will report the post to ChrisMac or RJ


thats a little thin skinned ain't it?

I mean, who would get so butt hurt over little ouchy words to do that?

who?

Why the Revered And Protected Werner Braun surely would report "personal insults" to RJ Spurrier
Dingus Milktoast

Gym climber
Maestro, Ecosystem Ministry, Fatcrackistan
Dec 10, 2014 - 11:22am PT
While one cannot say the Calgary flood was solely caused by climate change,
Compare the above with the previous statement you made:
-this was the cause of the Calgary flood.

This started with a global warming attribution to the current California drought. I don't buy it, not for a second.

DMT
Chiloe

Trad climber
Lee, NH
Dec 10, 2014 - 11:29am PT
The baby gets tossed with the bathwater.

Certainly a risk when climate statements appear exaggerated, though I think such exaggeration happens more in the media -- whose nature is to exaggerate all sorts of things -- than in the scientific reports themselves. The latter tend to be cautious and full of caveats, because the authors know what they don't know, and they also know their readers (including, competing research teams) are sharp too.

There was a grownup discussion of four recent reports about the California drought over at Skeptical Science recently. Two of these reports saw a role for climate change, while two did not, raising the question of why they seem to differ.

One takeaway is that the NOAA report considers the drought mainly as a (low) rainfall event, and finds that is not unprecedented. However, the actual drought has been not just a rainfall event, but low rainfall combined with high temperatures -- which NOAA evidently did not take into account. Two new papers in Geophysical Research Letters that do take temperatures into account give less reason for assuming there is no climate-change connection. As Griffin & Anchukaitis write,
The current California drought is exceptionally severe in the context of at least the last millennium and is driven by reduced though not unprecedented precipitation and record high temperatures.

Also in GRL, AghaKouchak et al. write
Global warming and the associated rise in extreme temperatures substantially increase the chance of concurrent droughts and heatwaves. The 2014 California drought is an archetype of an event characterized by not only low precipitation but also extreme high temperatures.... We argue that a multivariate viewpoint is necessary for assessing risk of extreme events, especially in a warming climate. This study discusses a methodology for assessing the risk of concurrent extremes such as droughts and extreme temperatures.

Neither of these GRL papers declares the recent drought was definitely caused by climate change, but they are describing what evidence they have.
Dingus Milktoast

Gym climber
Maestro, Ecosystem Ministry, Fatcrackistan
Dec 10, 2014 - 11:31am PT
Certainly a risk when climate statements appear exaggerated, though I think such exaggeration happens more in the media -- whose nature is to exaggerate all sorts of things -- than in the scientific reports themselves.

I tend to agree. Its the self-appointed spokespeople who make dire predictions like the clown I watched a decade ago say we had ten years to act.

I don't think such spokespeople realize the damage they do to credible science.

DMT
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