Hadley cells and warming

[Old Rocks]

Expansion of the Hadley cell under global warming: winter versus summer

Sarah M. Kang ∗

School of Urban and Environmental Engineering Ulsan National Institute of Science and Technology, Ulsan,

Republic of Korea Jian Lu Center for Ocean-Land-Atmosphere Studies,

Institute of Global Environment and Society, Calverton, Maryland, and

Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, Fairfax, Virginia

ABSTRACT A scaling relationship is introduced to examine the seasonality in the outer boundary of the Hadley cell in both climatology and trend. In climatological state, the summer cell reaches higher latitudes than the winter cell since the Hadley cell in summer deviates more from the angular momentum conserving state, resulting in weaker upper-level zonal winds, which enables the Hadley cell to extend farther poleward before becoming baroclinically unstable. The Hadley cell can also reach farther poleward as the ITCZ gets farther away from the equator, hence more Hadley cell extension in solstices than equinoxes. In terms of trend, a robust poleward expansion of the Hadley cell is diagnosed in all seasons with global warming. The scaling analysis indicates this is mostly due to an increase in the subtropical static stability, which pushes poleward the baroclinically unstable zone and hence the poleward edge of the Hadley cell. The relation between the trends in the HC edge and the ITCZ is also discussed.

http://wxmaps.org/jianlu/Kang_Lu_finalsubmission.pdf

Full article available at the site. The Hadley cells are extremely important to climate. A change of location, expansion or contraction, is of major consequence. And the evidence is that they are expanding at present.

 

[Old Rocks]

From a climatic point of view the extent of the tropical belt is important because it demarcates the zone dominated by a circulation pattern known as the Hadley cell (see graphic). This cell plays a major role in determining global patterns of rainfall. Near the equator the Hadley cell causes upward air currents that lead to lots of rainfall. At the poleward edges, the cell causes downward vertical motion and suppresses rain. It is no accident therefore that much of the world’s deserts are located in subtropics along the poleward edges of the tropical belt. Move those edges a bit to the north or south and you will likely see those deserts move as well.

What’s Been Happening to the Belt: A Short History
We all know that changes in the climate have been afoot. These include those that are most often talked about in the media such as rising global temperatures (see here, here and here) and melting ice (see here and here). Other trends may also be underway, such as more severe storms (see here and here) andweather extremes, but they have proven harder to establish in a statistically robust manner.

But here’s a trend I bet most people didn’t know about: the tropical belt has been expanding. The northern and southern edges of the belt have both moved on average about 100 miles further from the equator and closer to the poles over the past 30+ years.

A 100-mile expansion to the north and south in the tropical belt may not seem like a lot, but in fact it can have profound effects. For example, it could lead to a further drying or desertification of the subtropics. That could be especially problematic for already dry areas like the American Southwest.

Things to keep an eye on.

 

[flacaltenn]

Well -- for starters -- that would blow the CChanger projections of increasing drought in our desert SW. Because the boundary is about 30deg N or S. And getting BIGGER would push more weather into that region.

This effect is a "convenience" not a rule. Because there's a LOT of longitudes on the planet that are PLENTY moist throughout the outer boundaries of this zone. It's a struggle between THIS pattern of circulation and all the others.

 

[Old Rocks]

However, it is changing, and changing other things with it. As you pointed out, other factors involved, so the total effects are going to be hard to predict. Do you think that is a good thing?

 

[flacaltenn]

However, it is changing, and changing other things with it. As you pointed out, other factors involved, so the total effects are going to be hard to predict. Do you think that is a good thing?

Don't know enough about it. Don't know if it's another artifact of bad definitions -- like the sea ice stuff.
And I don't know how much historical variance has been documented.

COULD be somewhat periodic. COULD be interesting. But I doubt it's singularly controlled by "average global surface temperature" or increasing by 100 miles at every lattitude. Keep watching and add...

 

[Old Rocks]

Eolian sand in peridesert northwestern Libya and implications for Late Pleistocene and Holocene Sahara expansions

Abstract
Jebel Gharbi is a semi-arid mountain range on the northern boundary of the Sahara Desert, in northwestern Libya between the Mediterranean coastal plain (the Jefara) and the Tripolitanian Plateau. At Jebel Gharbi, Quaternary strata (dated by means of radiocarbon techniques and archaeological artifacts) consist of two Upper Pleistocene (Oxygen Isotope Stages 4 and 2) eolian sand beds that interfinger with loess, calcrete, alluvium, and colluvium. The deposition of the eolian sand was a consequence of the expansions of the Sahara Desert into the Jebel Gharbi area that took place during arid cold spells. During the latest Pleistocene and late Holocene, the northern margin of the Sahara Desert reached its modern position, and eolian activity was widespread on the Jefara coastal plain and in the valleys of Jebel Gharbi.

The Late Pleistocene desert expansions were contemporaneous with the periods of highest sedimentation rate of non-volcanic dust in polar ice cores. The comparison between data on eolian activity in some different places outside of the present boundary of the Sahara Desert suggest that there are differences in the timing of eolian sediment mobilization and the rate of eolian sediment deposition inside and outside the Hadley cell atmospheric circulation zone. The present work confirms the influence of the size of the Hadley cells on atmosphere dust circulation patterns.

Some indirect measurements of past Hadley cell movement.

 

[Old Rocks]

Expansion of the Hadley cell under global warming - Lu - 2007 - Geophysical Research Letters - Wiley Online Library

[3] The detailed response of the HC to increasing GHG is complex, as the HC is influenced by many factors, involving tropical heating processes [e.g., Mitas and Clement, 2006], the atmospheric stability [e.g., Schneider, 1977], extra-tropical eddy dynamics [e.g., Walker and Schneider, 2006], and total atmospheric moisture [Frierson et al., 2006]. To date, studies of the long term behavior of the HC, and the extent to which GHG forcing is relevant remain inconclusive. Atmospheric reanalyses show a statistically significant intensification of their Hadley circulation throughout the second part of the 20th century [Mitas and Clement, 2005]. However, this intensification is not found in the rawinsonde data, nor in most 20th century simulations using both coupled or atmosphere-only general circulation models (GCMs) [Mitas and Clement, 2005, 2006]. Meanwhile, simple physical arguments [e.g., Betts, 1998; Knutson and Manabe, 1995; Held and Soden, 2006] predict a slowdown of the overall tropical overturning circulation under global warming. Such a slowdown seems to be a robust feature in GCMs [Vecchi and Soden, 2007], and has been identified in observational analyses of the Walker circulation [Vecchi et al., 2005; Zhang and Song, 2006].

[4] However, it remains to be seen whether it also projects onto the zonally averaged part of the circulation. Analysis of the satellite observations indicates a poleward expansion of the HC over the past 27 years [Fu et al., 2006]. The extent to which this observed widening of the HC is primarily a response to GHG warming is not clear and warrants further investigation.

So, not a clear signal, but a signal none the less. Just another area that we are changing, with no idea as to what the changes will lead to. I really don't that is a wise course. Particularly considering the resident time of CO2 in the atmosphere.

 

[flacaltenn]

Second post clip --- just begs for more study. And says nothing new in that clip about "expansion" or broadening. Just references some other work. Instead thinks they find a "slowdown" connection to GW.

First line of that kinda confirms what my 1st reaction was -- that this construct of a circulation pattern has A LOT of influencing factors. Not just driven by a rise in MASTemperature.

But this is actual climate science. Can't make models until you understand the basics..
More money HERE. Less money on the hokum like temperature proxies and climate sensitivities..

 

[Old Rocks]

http://www.atmos-chem-phys.net/7/5229/2007/acp-7-5229-2007.pdf

Abstract. Using three meteorological reanalyses and three outgoing long-wave radiation (OLR) datasets, we show that the Hadley circulation has a significant expansion of about 2 to 4.5 degrees of latitude since 1979. The three reanalyses all indicate that the poleward expansion of the Hadley circulation in each hemisphere occurs during its summer and fall seasons. Results from the OLR datasets do not have such seasonality. The expansion of the Hadley circulation implies a poleward expansion of the band of subtropical subsidence, leading to enhanced mid-latitude tropospheric warming and poleward shifts of the subtropical dry zone. This would contribute to an increased frequency of midlatitude droughts in both hemispheres

Another paper. Yes, this is an area that needs a lot more study. The affects here will be major in the lives of millions of people.

 

[skookerasbil]

Second post clip --- just begs for more study. And says nothing new in that clip about "expansion" or broadening. Just references some other work. Instead thinks they find a "slowdown" connection to GW.

First line of that kinda confirms what my 1st reaction was -- that this construct of a circulation pattern has A LOT of influencing factors. Not just driven by a rise in MASTemperature.

But this is actual climate science. Can't make models until you understand the basics..
More money HERE. Less money on the hokum like temperature proxies and climate sensitivities..

Hey FlaCalTenn...........speaking about basics >>>

Cold sun rising - The Nation



Looks like in a few years, its gonna be getting ALOT fucking colder EVERYWHERE!!!

 

[Billy_Bob]

There has been much research in expansion and contraction of Hadley cells and the root causes of it.

One of note shows how cosmic radiation and solar wind are the primary drivers of the downward pressures and where they are placed on earths atmosphere.

http://dx.doi.org/10.1016/j.atmosenv.2011.04.027

Abstract
The galactic cosmic rays (GCRs) originating from astrophysical sources and traversing through the interstellar/interplanetary medium reach the terrestrial atmosphere and produce complex dynamic changes in it. The flow rate of GCRs incident on the Earth’s upper atmosphere is varied by the solar wind and the geomagnetic field. Striking correlations between the cloud cover and GCR fluxes on long time scale are observed whereas on short time scale no significant correlation is found. These observations are directly related to climate variations on short term as well as long term. In the present paper, we have reviewed and attempted to provide an overview of cosmic ray effects on terrestrial processes such as electrical phenomena, lightning discharges cloud formation and cloud coverage, temperature variation, space weather phenomena, Earth’s climate and the effects of GCRs on human health. It is shown that CRs control long term variations of some of the above mentioned physical processes, which in turn control short term and long term variations in climate. It is also pointed out that there are many basic phenomena which need further study and require new and long term data set.

As for there being any CO2 driven portion, there is no current evidence to support that supposition.

 

[Old Rocks]

Well, we heard that about this decade being a very cold one because of the dearth of sunspots. Now 2005, 2010, and 2014 were as warm, or nearly as warm, as 1998. And this year, 2015, will be warmer than 1998. That is four of the five warmest years on record in the last decade.

So now we have another prediction for a sun caused cooling in 2030. Well, we will see about that.

 

[Old Rocks]

http://www.sciencedirect.com/science/article/pii/S1352231011004055

Impact of galactic cosmic rays on Earth’s atmosphere and human health

Abstract
The galactic cosmic rays (GCRs) originating from astrophysical sources and traversing through the interstellar/interplanetary medium reach the terrestrial atmosphere and produce complex dynamic changes in it. The flow rate of GCRs incident on the Earth’s upper atmosphere is varied by the solar wind and the geomagnetic field. Striking correlations between the cloud cover and GCR fluxes on long time scale are observed whereas on short time scale no significant correlation is found. These observations are directly related to climate variations on short term as well as long term. In the present paper, we have reviewed and attempted to provide an overview of cosmic ray effects on terrestrial processes such as electrical phenomena, lightning discharges cloud formation and cloud coverage, temperature variation, space weather phenomena, Earth’s climate and the effects of GCRs on human health. It is shown that CRs control long term variations of some of the above mentioned physical processes, which in turn control short term and long term variations in climate. It is also pointed out that there are many basic phenomena which need further study and require new and long term data set.

Yes, much further study needed.

 

[flacaltenn]

Rocks ---- Take what you know about GW and apply it to this question of "broadening of Hadley cells"

1) Because of the stupid reduction of the GW to a single GLOBAL number, it's easy to forget that the majority of warming has occurred within 30deg of the poles.
2) Also know that in reality the stupid Global reduction of Climate Sensitivity to another single number, neglects the fact that the Earth has more than ONE climate zone with vastly different sensitivities and time constants to reach new equilibrium..

So -- a true MINORITY of the warming has even affected the tropics. Maybe less than 0.25DegC in 100 yrs. And the Climate sensitivity of the tropical zones is FAR LESS than many other latitudes. This minimizes the likelihood that observed changes these Hadley researchers THINK they've seen are GW related.

My reflexive reaction is this is far more likely a related effect to the "Stadium Wave" work by Currry et al. Where they attempted to track and quantify heat distribution waves -- wrapped tightly to latitude lines as they propagate from the Equator to the poles. The Hadleys probably pulse out in width as these waves appear and launch from the Equator.

Betcha if you search "Judith Curry" and "Hadley Cells" -- it will be in some of that work..

 

[Billy_Bob]

http://www.sciencedirect.com/science/article/pii/S1352231011004055

Impact of galactic cosmic rays on Earth’s atmosphere and human health

Abstract
The galactic cosmic rays (GCRs) originating from astrophysical sources and traversing through the interstellar/interplanetary medium reach the terrestrial atmosphere and produce complex dynamic changes in it. The flow rate of GCRs incident on the Earth’s upper atmosphere is varied by the solar wind and the geomagnetic field. Striking correlations between the cloud cover and GCR fluxes on long time scale are observed whereas on short time scale no significant correlation is found. These observations are directly related to climate variations on short term as well as long term. In the present paper, we have reviewed and attempted to provide an overview of cosmic ray effects on terrestrial processes such as electrical phenomena, lightning discharges cloud formation and cloud coverage, temperature variation, space weather phenomena, Earth’s climate and the effects of GCRs on human health. It is shown that CRs control long term variations of some of the above mentioned physical processes, which in turn control short term and long term variations in climate. It is also pointed out that there are many basic phenomena which need further study and require new and long term data set.

Yes, much further study needed.

Goldy Rocks, How can there be consensus on AGW when the physics of our atmosphere and the functions are not clearly understood? So you now admit there is insufficient knowledge on how our climatic systems work and that the science is not settled?

Nice to see that you admit there is no consensus and the it has always been a huge pile of BS..

This is progress..

 

[Old Rocks]

On the contrary, there is a near 100% consensus that we are affecting the atmosphere and oceans with the release of GHGs from our industries and transportation. How those affects take place, and how severe the effects will be is where there is disagreement. Thus far, far more has been affected than even the 'alarmists' predicted 30 years ago.

The polar regions have seen far more melting than predicted, as have the glaciers. Now that melting has not been in a nice linear line, in fact, only the ignorant expected that. It has varied as the natural variations. Same with the warming. The permafrost areas have seen far more warming than the Tropics. And, in both the tropics and the polar regions, the oceans have seen significant warming.

The physics of the absorption of IR by the various GHGs is clearly understood, and has been for nearly a century. We have refined the individual absorption spectra of the various gases, but the basic work was already done long ago.

Silly Billy, how can anyone that has messed up so completely on your predictions even pretend to be critical of the work of real scientists? The El Nino was and is exactly as predicted, and your constant predictions of immanent cooling were shown to be ridiculous.

The debate among those with any knowledge at all today is how fast and how severly AGW is going to impact all of us.

 

[CrusaderFrank]

http://www.sciencedirect.com/science/article/pii/S1352231011004055

Impact of galactic cosmic rays on Earth’s atmosphere and human health

Abstract
The galactic cosmic rays (GCRs) originating from astrophysical sources and traversing through the interstellar/interplanetary medium reach the terrestrial atmosphere and produce complex dynamic changes in it. The flow rate of GCRs incident on the Earth’s upper atmosphere is varied by the solar wind and the geomagnetic field. Striking correlations between the cloud cover and GCR fluxes on long time scale are observed whereas on short time scale no significant correlation is found. These observations are directly related to climate variations on short term as well as long term. In the present paper, we have reviewed and attempted to provide an overview of cosmic ray effects on terrestrial processes such as electrical phenomena, lightning discharges cloud formation and cloud coverage, temperature variation, space weather phenomena, Earth’s climate and the effects of GCRs on human health. It is shown that CRs control long term variations of some of the above mentioned physical processes, which in turn control short term and long term variations in climate. It is also pointed out that there are many basic phenomena which need further study and require new and long term data set.

Yes, much further study needed.

Further study on "Settled science"?

Why?

I thought you eliminated all the variables except for a 10PPM of CO2?

That's a joke site, right? Cosmic rays affect Earth climate = LOL. Cosmic ray is another way of saying CO2 right? I mean the statement "medium reach the terrestrial atmosphere and produce complex dynamic changes in it" is Denier speak, right?

 

[CrusaderFrank]

Well, we heard that about this decade being a very cold one because of the dearth of sunspots. Now 2005, 2010, and 2014 were as warm, or nearly as warm, as 1998. And this year, 2015, will be warmer than 1998. That is four of the five warmest years on record in the last decade.

So now we have another prediction for a sun caused cooling in 2030. Well, we will see about that.

Sure, when you adjust the satellite data and add in the deep ocean, it's a heat wave ferchristsake!

 

[Crick]

Thousands of people are involved in measuring, processing and recording climate data. The likelihood that every single one of them is a member in good standing of a conspiracy to lie to the American people about those data in return for their job security is more than a little slim. Surely, somewhere in all those thousands of people, over the decades that this would have to have been going on, SOMEONE would have squealed. Yet not one single such testimony has appeared. Not ONE. And even people generally on your side of the argument - ex: Judith Curry - have expressed the opinion that the grand conspiracy theory is completely unsupportable.

Yet, you carry on.

 

[CrusaderFrank]

Thousands of people are involved in measuring, processing and recording climate data. The likelihood that every single one of them is a member in good standing of a conspiracy to lie to the American people about those data in return for their job security is more than a little slim. Surely, somewhere in all those thousands of people, over the decades that this would have to have been going on, SOMEONE would have squealed. Yet not one single such testimony has appeared. Not ONE. And even people generally on your side of the argument - ex: Judith Curry - have expressed the opinion that the grand conspiracy theory is completely unsupportable.

Yet, you carry on.

You're a perfect example that people will lie, repeatedly, when the goal is to get control of a $4 trillion economy.