I liked this part:
According to the study an important issue remains as to why the poleward expansion is largest in autumn, and there is still uncertainty about the role of external forcings – such as greenhouse gases – as climate models underestimate the southward expansion of the Hadley cell edge.
From CSIRO Australia
Southern Hemisphere becoming drier
A decline in April-May rainfall over south-east Australia is associated with a southward expansion of the subtropical dry-zone according to research published today in Scientific Reports, a primary research journal from the publishers of Nature.
CSIRO scientists Wenju Cai, Tim Cowan and Marcus Thatcher explored why autumn rainfall has been in decline across south-eastern Australia since the 1970s, a period that included the devastating Millennium drought from 1997-2009.
Previous research into what has been driving the decline in autumn rainfall across regions like southern Australia has pointed the finger at a southward shift in the storm tracks and weather systems during the late 20th century. However, the extent to which these regional rainfall reductions are attributable to the poleward expansion of the subtropical dry-zone has not been clarified before now.
Mr Cowan said rainfall patterns in the subtropics are known to be influenced by the Hadley cell, the large-scale atmospheric circulation that transports heat from the tropics to the sub-tropics.
“There has been a southward expansion of the edge of the Hadley cell – also called subtropical dry-zone – over the past 30 years, with the strongest expansion occurring in mid-late autumn, or April to May, ranging from 200 to 400 kilometres,” Mr Cowan said. The CSIRO researchers found that the autumn southward expansion of the subtropical dry-zone is greatest over south-eastern Australia, and to a lesser extent, over the Southern Ocean to the south of Africa.
“The Hadley cell is comprised of a number of individual branches, so the impact of a southward shift of the subtropical dry-zone on rainfall is not the same across the different semi-arid regions of the Southern Hemisphere,” says CSIRO’s Dr Wenju Cai.
The researchers tested the hypothesis that the dry-zone expansion would give rise to a southward shift in the average rainfall during April and May, and questioned how rainfall across semi-arid regions, including southern-coastal Chile and southern Africa, would be affected.
“During April and May, when the dry-zone expansion is strong, rainfall over south-eastern Africa, south-eastern Australia and southern-coastal Chile is higher than over regions immediately to their north,” Dr Cai said.
Using high-quality observations and an atmospheric model the CSIRO team found that for south-eastern Australia, up to 85% of recent rainfall reduction can be accounted for by replacing south-eastern Australia rainfall with rainfall 400km to the north. Such a southward shift of rainfall can explain only a small portion of the southern Africa rainfall trend, but none of the autumn drying observed over southern Chile.
“For south-east Australia, autumn is an important wetting season,” Dr Cai explained. “Good autumn rainfall wets the soil and effectively allows for vital runoff from follow-on winter and spring rain to flow into catchments.”
According to the study an important issue remains as to why the poleward expansion is largest in autumn, and there is still uncertainty about the role of external forcings – such as greenhouse gases – as climate models underestimate the southward expansion of the Hadley cell edge.
This research was conducted through CSIRO’s Water for a Healthy Country Flagship, and was funded by the Goyder Institute for Water Research and the Australian Climate Change Science Programme. Wenju Cai, Tim Cowan and Marcus Thatcher are from CSIRO’s Marine and Atmospheric Research division.
UPDATE:
Some commenters can’t look beyond the title and see the bigger picture, so here’s an update just for them. Note that the study deals with the Hadley cell, which is NOT regional, but hemispherical. They looked not only at Australia, but also rainfall in southern-coastal Chile and southern Africa.
This is where I was coming from, which I thought would be obvious to anyone who’s been following the positive water vapor feedback issue for any length of time.
http://www.gfdl.noaa.gov/bibliography/related_files/hall0001.pdf
===============
Abstract. Using two versions of the GFDL coupled ocean-atmosphere model, one where
water vapor anomalies are allowed to affect the longwave radiation calculation and one
where they are not, we examine the role of water vapor feedback in internal precipitation
variability and greenhouse-gas-forced intensification of the hydrologic cycle. Without
external forcing, the experiment with water vapor feedback produces 44% more annualmean, global-mean precipitation variability than the one without.
We diagnose the reason for this difference: In both experiments, global-mean surface temperature anomalies are associated with water vapor anomalies. However, when water vapor interacts with longwave radiation, the temperature anomalies are associated with larger anomalies in surface downward longwave radiation. This increases the temperature anomaly damping through latent heat flux, creating an evaporation anomaly.
The evaporation anomaly, in turn, leads to an anomaly of nearly the same magnitude in precipitation. In the experiment without water vapor feedback, this mechanism is absent. While the interaction between longwave and water vapor has a large impact on the global hydrologic cycle internal variations, its effect decreases as spatial scales decrease, so water vapor feedback has only a very small impact on grid-scale hydrologic variability. Water vapor feedback also affects the hydrologic cycle intensification when greenhouse gas concentrations increase. By the 5th century of global warming experiments where CO2 is increased and then fixed at its doubled value, the global-mean precipitation increase is nearly an order of magnitude larger when water vapor feedback is present.
The cause of this difference is similar to the cause of the difference in internal precipitation variability: When water vapor feedback is present, the increase in water vapor associated with a warmer climate enhances downward longwave radiation. To maintain surface heat balance, evaporation increases, leading to a similar increase in precipitation. This effect is absent in the experiment without water vapor feedback. The large impact of water vapor feedback on hydrologic cycle intensification does not weaken as spatial scales decrease, unlike the internal variability case. Accurate representations of water vapor feedback are therefore necessary to simulate global-scale hydrologic variability and intensification of the hydrologic cycle in global warming.
=================
So if positive water vapor feedback were occurring, based on this idea, we’d see an “intensification of the hydrologic cycle”, i.e. more rainfall, runoff, and evaporation. That would apply to the southern hemisphere continents too.
And the researchers by their own admission can’t even fit GHG feedbacks into the Hadley cell migration equation successfully. It is just more evidence of uncertainty in the “settled science” of AGW.
Dale @ur momisugly 1:01 pm:
Yes, in Melbourne a few years ago you could always rely on getting a dose of Perth’s weather 3 days later. Not so more recently.
What’s the point? As Lindzen has shown. all of the models have feedback from water vapor which is just opposite to the feedback operating in nature. If the models are inherently unreliable, how they change with tweaks of individual model parameters (whether it be in relation to CO2 or water vapor) is irrelevant.
“So if positive water vapor feedback were occurring, based on this idea, we’d see an “intensification of the hydrologic cycle”, i.e. more rainfall, runoff, and evaporation. That would apply to the southern hemisphere continents too.”
The only “positive water vapor feedback” or “intensification of the hydrologic cycle” only happen in the “Gore Effect”.
Dear Mr CSIRO, We live in country SE Oz and though I don’t know about the science I can tell you our water tanks are full. Perhaps you could risk leaving your laboratory and get your “model” to stick its head into the tank to check?
Once again the task shall fall to CSIRO to show to Australia and the world the proven damages wrought by Anthropogenic Climate Change. The models are in agreement, now backed by real world confirmed evidence. There is only one solution to save Australia from the horrendous ravaging drought to come.
Build more desalinization plants.
Hopefully CSIRO will be able to bring about this certain cure for ACC before the Great Barrier Reef is irrevocably destroyed beyond any hope of recovery, again.
More or less, here is whats being spoken of:
http://www.bom.gov.au/cgi-bin/climate/change/timeseries.cgi?graph=high_density&area=sth&season=0305&ave_yr=0
Looks like quite a signal, although it is lacking the last 3 years worth of SH autumn data (including this autumn). That’s interesting because there has been plenty of autumn rain during the last three years:
http://www.bom.gov.au/cgi-bin/climate/change/timeseries.cgi?graph=rranom&area=seaus&season=0305&ave_yr=0
with 2010, 2011, and 2012 autumn rainfall anomaly being + 18, 0, and 41 mm respectively.
But that does fit the anthropogenic alarmist dogma, which is why the omit the month of march, because as you can see here (I know, its s good one):
http://www.bom.gov.au/cgi-bin/climate/change/timeseries.cgi?graph=rranom&area=seaus&season=03&ave_yr=0
It’s been bucketing down in march!!!, resulting in record flooding. In fact, the 2012 march rainfall for south eastern Australia was the HIGHEST on record.
Now, for the alarmist at heart, this is not a problem, since it can be argued that the recent March anomalies where due to unseasonal tropical rainfall, and that of course can be blamed away on global warming.
One problem though, do they really expect us to believe they know the source of all the March rainfall events since 1900? I mean seriously, who the f@ur momisugly@k are these people!
Tropical, extra tropical, sub polar, etc…? You only have that data since the 1980’s, which is why I’m still looking for that radial button which diverts funding from these cargo cult hacks.
Rosco, Nelson, and others have got that right. CSIRO “science”: By the government, for the government. The propaganda that CSIRO churns out, at the public’s expense, is no more reliable than its models. They don’t even have the right balance of energy.
http://www.climatedepot.com/a/17674/Climate-scientist-Dr-Murry-Salby-explains-why-manmade-CO2-does-not-control-climate
Who cares how one of their internal cogs affects another? Yet, those models are the excuse for building expensive but pointless desalination plants, which have inflated water costs, and our big new tax burden, through which power bills have jumped dramatically.
This must be the payoff of “Trickle Down Government”.
Oxygen isotopes in tree rings are a good proxy for Amazon precipitation and El Niño-Southern Oscillation variability</code?http://www.pnas.org/content/early/2012/09/27/1205977109
Oxygen isotopes in tree rings are a good proxy for Amazon precipitation and El Niño-Southern Oscillation variabilityhttp://www.pnas.org/content/early/2012/09/27/1205977109
Most people are missing the whole point. Is it supposed to be raining more from positive feedback, or less? Are they just changing theories as they go along? First it was droughts, but that didnt work. Then the floods came and that went out the window. Now its been dry in Perth during Autumn and its the Hadley cell.
Why wouldnt you look at this instead, since the warm PDO the Southern Annular mode has been predominately positive.
http://www.lasg.ac.cn/staff/ljp/data-NAM-SAM-NAO/SAM(AAO).htm
Now we are in the Cold PDO, lets see if it responds for the next 30 years the other way. The thing to come out of it is no one knows for sure. They are throwing theories around left right and centre in the hope one is right.
Ok – this I can understand. There are a lot of people that are big on decrying the well-understood CO2 heating (as a result of doubling blah blah blah) but can’t begin to get past the 1.2ºC limit of that doubling. Meaning they ignore that a lot of knock-on forcings absolutely have to happen for global warming to be a bother and nobody knows if these forcings are net positive or net negative.
But – according to Planet Earth, that big ball under our feet, and the output created by defective but never the less the very best climate models available, the forcings are not positive else there would not be a growing divergence between projected and observed temperatures.
You will find not shortage of experts who will decry the direct warming of CO2 (which is unimportant and would have happened even without human intervention given the natural growth of CO2) but who cannot close the deal by showing the process by which forcings finish the job CO2 starts (Mosher, for example).
Seeing the name “Thatcher” attached to anything connected with climate gives me the shivers.
But I’m sure this stuff is consistent with the AGW conjecture. Everything, no matter what, is.
To Dp,
I have had a go around before with the person named richardscourtney who scolded you above for seriously considering my comment. FYI, in that go around, I learned that he has no demonstratable background in science, in general, and certainly no record of contribution to climate science. In addition, when drawn into a discussion of the simplest aspect of climate science, I found that he cried foul and ran for cover, asking the moderator to ban me instead of him from participation in WUWT. Yet he is encourage to pontificate very regularly at WUWT for reason I do not know. It must have something to do with the clever British put downs that litter his comments. While that are they carry no content and come from nowhere scientific.
On the other hand, I have a very long record of accomplishment in the field of atmospheric science that was been domonstated and can be inspected at ericgrimsrud.com. Therefore, there is a distinct possiblity that you might just happen to be in better company when you also noted that the problem I immediately had with the title of this post.
Cheers to you and, of course, his excellency, Sir Richardcourney, whoever you are.
That’s odd! I am a PhD geoscientist directing a small consultancy in SE Australia specializing for the last 15 years in surface and shallow groundwater management and impact assessment for the mining industry. There is a frequent call for us to construct Cumulative Monthly Rainfall Residual Plots at a wide range of long term rainfall monitoring stations – most BOM (Bureau of Meteorology) stations. We do this in order to better interpret shallow groundwater level trends, small catchment productivity trends etc. above or in proximity to underground mining (which produces mine subsidence). We typically use long term monthly records going back to 1970 – 1980 to establsihed long term mean monthly rainfalls.
In actual fact, in recent years, following the drying trend of the 2001 – 2006 Millenium Drought (which BTW was a drying trend that following an even longer wetting trend) monthly rainfalls (in SE Australia) have moved more or less back into proximity e.g. within one standard deviation, to the long term means of the 1970/1980 – 2011, 30 – 40 year period. There is no evidence of a significant drying relative to the long term means of the last 30 – 40 years except at a very few locations.
How about some real data?
Source: Ken Gregory
http://www.friendsofscience.org/assets/documents/FOS%20Essay/Climate_Change_Science.html#Water_vapour
Sadly, today’s C(anti-)SIRO creates mountains out of statistical molehills. Try a full set of data from 100+ years, eg., Condobolin in the wheat belt. Total annual rainfall trend (1890 to 1911) is upward and autumn rainfall shows no trend at all. Even from 1970- there is no “drying-out” if 2008-11 is included. These people are shameless propagandists, not scientists.
As a resident of Perth, Western Australia, it has seemed to me that these days we get rain from warm tropical moist air more frequently than we used to, and rain from southern cold fronts less frequently.
So I’d agree that the weather patterns seem to be moving south, away from the equator.
These people badly need to read up on world climates:
“semi-arid regions, including southern-coastal Chile ”
Southern coastal Chile is one of the wettest places in the World. Presumable they are thinking of northern coastal Chile, which is indeed arid.
There can be no GHG-AGW because GHG thermal emission from the atmosphere annihilates that band emission from the Earth’s surface.
The physics is very simple: the net UP IR in any wavelength interval at the surface is the vector sum of the Poynting vectors arriving at that point. This is required by Poynting’s Theorem, the most basic axiom derived from Maxwell’s Equations.
Engineers like me calculate this from the difference of the S-B emission from the bodies in radiative equilibrium. So every GHG atmospheric thermal emission band reduces the equivalent emission from the surface. The Aarhenius GHG blanket is not possible and anyone who believes in it betrays their lack of basic physics’ knowledge.
The addition of ‘back radiation’ to net UP IR in the Trenberth ‘Energy Budget’ recreates the UP Poynting vector, most of which can do no thermodynamic work.
The real GHE is mostly the result of the rise in temperature needed to overcome reduced surface emissivity. Check this argument with any physics’ professional and they will confirm I am right.
ericgrimsrud:
At October 4, 2012 at 8:16 pm you claim
Allow me to save people the time of conducting that “inspection” by listing your entire
very long record of accomplishment in the field of atmospheric science.
1.
Read SKS.
2.
Wrote an ebook that gets almost everything wrong.
3.
Paid to publish the ebook at your own expense.
4.
Visited WUWT and made a fool of yourself in various ways; e.g. called davidmhoffer and myself “feces” for pointing out your mistakes.
5.
At October 4, 2012 at 8:16 pm on this thread claimed to have a very long record of accomplishment in the field of atmospheric science.
Richard
Another nail in the GHG theory. Keep them coming.
Increased water vapour in the atmosphere will adsorb more SIR and emit more LIR to cause more evapouration etc.
Oh dear! More computer simulated “science” from the CSIR “Cane Toads are good” O. Along with my sides, my Playtex 24 girdle is showing signs of wear from laughter!
“External forcings such as green house gases”. What sort of statement is that! External to what? The world, are these CO2 molecules attenuated out in space and emitting evil forcings at the Earth. My understanding of a forcing is the gaining of entry through a door by breaking it down.
Using real speak it could be interpreted as “external forces such as the sun”
That however may lead to a lesser career path and pay cheque. These people really need to just do the science and stop the BS.
ericgrimsrud says:
“I learned that (Richard Courtney) has no demonstratable background in science, in general, and certainly no record of contribution to climate science.”
Where did you “learn” that? If I am not mistaken, Mr Courtney is a published, peer reviewed author.
You may post your apology here.
Here is the current water vapour levels back to 1948 and the IPCC water vapour forecast which will be in AR5 going out to the year 2100.
http://s19.postimage.org/pk8wtzxqr/WV_IPCC_AR5_Forecast_2100.png
And then more of a close-up going out to just 2020 where we can also see that the ENSO is the dominant control mechanism of global water vapour levels (which lag behind it by 3 months – this is one of the most important climate drivers there is, global water vapour levels – this relationship is taken advantage of by the climate science community since any paper dealing with water vapour levels deliberately starts their analysis in a La Nina and ends in an El Nino so they can show an increase in water vapour levels – they should instead be trying to understand why the ENSO is so dominant here and what the implications of that are.)
We can also see that the “hindcast” of IPCC AR5 which should be using actual observational data up to about 2010 is already way off of the actual values. IPCC AR5 has water vapour levels up by 5.4% already and have it increasing by 23.5% by 2100 (similar to the theory that water vapour should increase by about 7.0% per 1.0C increase in temperatures – so they have just built this theory directly into the models – it is needed to get to 3.0C per doubling – perhaps that is why the ENSO relationship is so downplayed – because it would throw a wrench into 3.0C per doubling if the ENSO continues its historic pattern of no trend over the long-term.)
The theory is missing something very important here.
http://s19.postimage.org/rnjc1nxjn/WV_IPCC_AR5_Forecast_ENSO_Sept2012.png