How Pressure Systems Control Climate Part 2: ITCZ, Rainforests And Deserts

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Jim Steele

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This is part 2 in my educational series on Climate Science

Here you’ll see how the ITCZ  determines the location of rainforests and deserts

In contrast to media narratives that global warming causes higher temperatures and drought, you will see, conclusively, why droughts and dryness cause higher temperatures and how reduced transport of moisture from the oceans to the land causes drought.

You will see that during the coldest periods of the last 10,000 years, societies experienced the worst droughts,

And contrary to media narratives, the science shows warmer temperatures will bring more rain.

A transcript of this video is available at

https://perhapsallnatural.blogspot.com/2022/01/how-pressure-systems-control-climate.html

Jim Steele is Director emeritus of San Francisco State University’s Sierra Nevada Field Campus, authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism, and proud member of the CO2 Coalition.

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Duane
January 4, 2022 2:09 pm

It’s pretty basic physical chemistry that the warmunists are ignoring:

Water at a higher temperature has a higher vapor pressure, meaning a stronger gradient producing evaporation to the air. Air at a higher temperature progressively holds a greater mass of water vapor proportional to the mass of gaseous air. The net effect is that more water evaporates from the oceans where it is transported to land as precipitating as fresh water – rain or snow.

Of course natural systems are far more complex then just the relationships affecting evaporation and precipitation, and cannot be modeled by any single process as warmunists always try to argue.

griff
Reply to  Duane
January 4, 2022 2:13 pm

The climate scientists are not ignoring it – it is cited as a reason for the (increasing number of) extreme rain events

Vuk
Reply to  griff
January 4, 2022 2:36 pm

Hi Griffo
I don’t know about that one, I bet you didn’t know about this one. Will update it one of those days

AHA3.gif
Anthony Banton
Reply to  Vuk
January 4, 2022 3:17 pm

Will update it one of those days”

Don’t bother – the EPA have done it for you (Atlantic ACE) ….

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meab
Reply to  Anthony Banton
January 4, 2022 3:26 pm

You’re attempting to deceive AGAIN Bantam Weight. You’ve cherry-picked just the part of the world where accumulated cyclone energy has risen. Overall, across the globe it’s declining. Fortunately, you are feckless at spreading your false message of an ongoing climate crisis – it is not happening.

MarkW
Reply to  Anthony Banton
January 4, 2022 7:53 pm

1) we have records going back way before 1950. Why cut off the data prior to 1950?
2) I’m not seeing a steady increase, instead I’m seeing a cycle of approximately 60 years. Hmm, what well known climate cycle has a 60 year period and has recently peaked?

Tom Abbott
Reply to  Anthony Banton
January 5, 2022 3:33 am

“Don’t bother – the EPA have done it for you”

That sounds ominous.

Reply to  griff
January 4, 2022 2:56 pm

Global warming theory was designed to be idiot proof. No matter what happens, it can always be blamed on CO2, so that idiots like Griff don’t need to think at all to agree.

Tom Abbott
Reply to  Jim Steele
January 5, 2022 3:35 am

“Global warming theory was designed to be idiot proof.”

That sums it up nicely. That’s the reason for all the ambiguous language associated with “climate change”.

Last edited 6 months ago by Tom Abbott
meab
Reply to  griff
January 4, 2022 3:33 pm

The IPCC has found no evidence of increased flooding in their latest analysis report, griffter. They have seen increases in rainfall but no increase in flooding. To be honest, you should have said that, but you have no intention of being honest. Instead, you always try to spread your false narrative that there’s a climate crisis. There isn’t.

commieBob
Reply to  griff
January 4, 2022 5:27 pm

LOL

Once again our dear griff says something that is factually correct. Alarmist climate scientists do indeed cite this basic physical principle as a reason for the increasing number of extreme rain events.

By accident or by choice, our dear griff does not actually say that the alarmist climate scientists are correct. He just reports what they are saying.

Here griff, I’ll resolve any ambiguity and fix it for you.

The alarmist climate scientists are not ignoring it – it is wrongly cited as a reason for the (nonexistent increasing number of) extreme rain events

Last edited 6 months ago by commieBob
Duane
Reply to  griff
January 4, 2022 5:30 pm

There AREN’T an increasing number of extreme rainfall events. And I did not write that the sea and atmosphere are warming. I wrote that the warmunists are wrong when they stupidly claim that global warming causes droughts.

MarkW
Reply to  griff
January 4, 2022 7:48 pm

As usual, griff repeats the mantra without even once bothering to think about what it is writting.
The claim is that warmer air can hold more water.
1) As long as the air remains warm, it will continue to hold that water, extra rainfall is not possible.
2) Extra evaporation is a very, very strong negative feedback that none of the models incorporate.

PCman999
Reply to  MarkW
January 4, 2022 11:53 pm

Careful – you made a mistake with 1) – the gentle warming that the Earth has experienced since 1975 is leading to more evaporation from the oceans’ tropic and equatorial regions, which eventually comes down as rain in cooler areas. The Sahel region is expanding into the Sahara, it’s snowing more in N. California, and generally the world is greening, with thanks to higher CO2 levels as well.

ironargonaut
Reply to  griff
January 5, 2022 5:36 pm

Yes they are. Temperature is not a unit of energy. If you use gas law for energy calculations need to account for amount molecules in air and pressure. They do not have long enough history or enough of those measurements to claim CAGW. Using temperature alone is fundamentally flawed.

griff
January 4, 2022 2:11 pm

and yet global warming also causes drought and heatwaves and extreme precipitation: 2021 shows that clearly

Reply to  griff
January 4, 2022 2:22 pm

You show to be confused with cause and effect 😀
Nothing new so far 😀

Reply to  griff
January 4, 2022 2:26 pm

… and hair loss, toe fungus, the heartbreak of psoriasis, impotence, …

By golly, temperature variation causes just about everything! Griff, I think you’re onto something! While you are at it, please tell me, oh wise one, what is the optimum global temperature to which we should aspire, yielding an eden on all the earth?

John Bell
Reply to  griff
January 4, 2022 2:28 pm

CC causes EVERYTHING, droughts and floods, and hot and cold and cool and warm, and snow and no snow, and on and on… we have your number!

Tom Halla
Reply to  griff
January 4, 2022 2:44 pm

Yeah, Griff, the Little Ice Age had such pleasant weather/snarc

MarkW
Reply to  Tom Halla
January 4, 2022 8:03 pm

Climate models can’t reproduce the Little Ice Age, therefore the LIA did not occur.

Mr.
Reply to  griff
January 4, 2022 3:23 pm

Did you read about the December all-time record snowfall for the Sierra Nevada range Griff?

By your hypothesis, global warming must have been turned up to 11 there?

meab
Reply to  griff
January 4, 2022 3:35 pm

You’re lying AGAIN, griffter. The IPCC has found no evidence of any increase in drought in their latest analysis report AR6.

MarkW
Reply to  meab
January 4, 2022 8:04 pm

Who are you going to believe, the IPCC or the Guardian?

Pat from kerbob
Reply to  griff
January 4, 2022 5:31 pm

Griff, as has clearly been shown with actual data, extreme weather has decreased over the last few decades. Cherry picking some above average events of 2021 does not disprove the long term data.
As noted, for every example of a location that saw a rain or flood event I can list a hundred that had none

MarkW
Reply to  Pat from kerbob
January 4, 2022 8:16 pm

Also, for every place that showed a significant rain event, you can show that similar type events have occurred many times in the past.

Tom Abbott
Reply to  MarkW
January 5, 2022 3:58 am

Yes, there is no unprecedented weather, even in the history we know. Saying something is unprecendented in weather considering the amount we don’t know about the history of weather is just pure speculation. Unknowable.

DD More
Reply to  Pat from kerbob
January 5, 2022 2:44 pm

Pat, and Griff needs to take the following quiz.
Which three of the following states have the record high temperatures.
Alabama – Florida – South Carolina – Montana – North Dakota or South Dakota?

If you guessed the Southern states, you would be wrong. The reason is not Latitude but Humidity. It’s ‘Dry and Hot’, not ‘Hot and Dry’
By the way only 2 or 50 states have set their records in the 2000’s, and South Dakota only tied theirs from the 1920’s.

Florida 109 – June 29, 1931 Monticello
Alabama 112 – Sept. 5, 1925 Centerville
Montana     117 – July 5, 1937 Medicine Lake
North Dakota 121 – July 6, 1936 Steele
South Carolina 113 – June 29, 2012 Columbia
South Dakota 120 – July 15, 2006 Fort Pierre

MarkW
Reply to  griff
January 4, 2022 8:01 pm

No matter how disproven the lie, griff will repeat it as long as the paychecks don’t bounce.
There has been no increase in droughts, heatwaves, flooding, or anything else.
griff’s lie depends on two pieces of ignorance. First he completely ignores any weather events that happened more than a decade or two ago. Secondly he only cares about weather events that get lots of media coverage.

Clyde Spencer
Reply to  griff
January 4, 2022 9:49 pm

You left out that global warming also causes the heart break of psoriasis!

Tom Abbott
Reply to  griff
January 5, 2022 3:46 am

“and yet global warming also causes drought and heatwaves and extreme precipitation: 2021 shows that clearly”

This is the way obsessed people think.

Last edited 6 months ago by Tom Abbott
Herbert
January 4, 2022 4:01 pm

Jim,
In support of your position that “contrary to media narratives, the science shows more temperature will bring more rain”, Professor Andy Pitman at the SEI Forum at University of Sydney on 19 June,2019 stated-
“….this may not be what you expect to hear, but as far as the climate scientists know there is no link between climate change and drought.
That may not be what you read in the newspapers and sometimes hear commented, but there is no reason, a priori, why climate change should make the landscape more arid.”
Subsequently Professor Pitman rowed back from his position by stating there was an “indirect” connection between drought and climate change.
See: joannenova.com.au-
“Prof.Andy Pitman admits droughts are not worse and not linked to climate change”, August 19, 2019.
I read regularly in the Australian press that climate predictions indicate that the world (and Australia) is getting hotter and drier.
It is a difficult mantra to overcome but we must keep arguing for the truth.
In fact, the theory of “ the enhanced greenhouse effect” requires that the water and cloud feedback be strongly positive.
Hotter and drier will not push ECS or world warming substantially above the 1.2C known for well over a century for a doubling of CO2 in laboratory conditions.

commieBob
Reply to  Herbert
January 4, 2022 5:44 pm

Hotter and drier will not push ECS or world warming substantially above the 1.2C known for well over a century for a doubling of CO2 in laboratory conditions.

Bingo. James Hansen postulated a feedback effect that would raise the ECS above what CO2 alone could account for. The most important greenhouse gas is water vapor. The small warming due to increased CO2 would cause evaporation which would result in even more warming due to more water vapor in the atmosphere.

If the atmosphere becomes drier, that would (according to the alarmists’ own theory) reduce the ECS. Oh dear! 🙂

Ulric Lyons
January 4, 2022 4:44 pm

Water vapour absorbs on average about a third of the solar near infrared, so with the drier air in the Horse Latitudes the surface receives more heating from solar near infrared.

RickWill
January 4, 2022 6:05 pm

but it migrates further north and south over Asia and Africa because land masses heat up faster than the ocean

It appears you are unaware of the fact that ocean surfaces are coolest when their heat uptake is maximum in December. It is not delayed heating. The ocean surface temperature is inverse to the net evaporation rate.

This paper may give you better insight into what is actually going on:
https://wattsupwiththat.com/2021/11/14/global-water-cycle/

The title chart makes the point. Ocean surface temperature is completely out of phase with ocean heat uptake. Oceans are coolest when net evaporation is at its maximum.

Oceans are not being warmed or cooled by the surface radiation. Increased surface radiation increases the upwelling causing the surface to cool and reduce ocean heat content.

The fact that ocean surfaces are warming is proof that the net water cycle, ocean to land, is slowing down. That has been occurring for the last 400 years as the precession cycle advances and perihelion gets progressively later each year.
https://hess.copernicus.org/articles/24/3899/2020/

The net water cycle will trend downward for the next 10,000 years. But more of the water will be retained on land as boreal winters get colder.

commieBob
Reply to  RickWill
January 4, 2022 6:56 pm

You may not have been clear enough for my poor ancient addled brain. Is there a process by which the oceans gain heat or have they been steadily cooling since the formation of the planet?

Reply to  RickWill
January 4, 2022 7:59 pm

It’s not clear at all what point you are trying to make regards the ITCZ’s position.The ITCZ migrates towards the warmest hemisphere.You seem to disagree in a very obtuse snarky way there was something wrong with the statement “but it migrates further north and south over Asia and Africa because land masses heat up faster than the ocean”

So specifically explain clearly 2 things.

1) why does the ITCZ extend to a greater degree towards the Tropic lines during each hemisphere’s summer over land but less so over the oceans

2) Despite the southern hemisphere summer coinciding with perihelion and thus experience greater insolation than the northern, the ITCZ does not, on average, extend south of the equator over the oceans.

It “appears you are unaware of the fact” that has nothing to do with insolation but ocean heat transport northward.

Reply to  Jim Steele
January 4, 2022 8:02 pm

As illustrated here

itcz.jpg
RickWill
Reply to  Jim Steele
January 4, 2022 8:22 pm

Specially I am making the point with regard your comment about the land heating up faster than the oceans.

The fact is that the oceans surface warming is exactly in concert with the land surface warming albeit oceans have a small temperature range while land has a large temperature range. The temperature change in both are in phase.

Ocean surface are coolest when their heat uptake is at a maximum in December and heat transfer to the land, through latent heat transfer, is also at its maximum.

Ocean surface are coolest when the water cycle, ocean to land, is at its maximum in December. Ocean surface warming (temperature) is not a function of surface heat input. In fact it is the inverse. The more heat input to oceans, the greater the net evaporation and the cooler the surface. More heat input speeds up the upwelling thereby bringing cooler water to the surface.

The WUWT paper I linked to explains that in detail with actual measured data.

No climate model has predicted the observed downward trend in net evaporation that has occurred over the past 50 years.

Last edited 6 months ago by RickWill
Reply to  RickWill
January 4, 2022 8:44 pm

You are just repeating yourself and going off topic again, but not answering my question

RickWill
Reply to  Jim Steele
January 4, 2022 10:06 pm

1) why does the ITCZ extend to a greater degree towards the Tropic lines during each hemisphere’s summer over land but less so over the oceans

Land temperature responds directly with solar input and warms up as insolation increases. Ocean surface temperature responds to the inverse of solar input but does not change much. Point here is that both ocean and land warm up in phase but the range of temperature change on land is greater.

2) Despite the southern hemisphere summer coinciding with perihelion and thus experience greater insolation than the northern, the ITCZ does not, on average, extend south of the equator over the oceans.

The ocean surface is coolest when insolation and its neat heat uptake is at maximums in December and January. That is the time of maximum heat transfer to land through latent heat transport from ocean to land. Land has its highest heat loss in December so the ocean heat transfer reaches its maximum as evidence by land rainfall being maximum in December and January.

In fact the best available data confirms that global river runoff has declined over the last 50 years:
https://hess.copernicus.org/articles/24/3899/2020/
And:
https://www.bafg.de/GRDC/EN/03_dtprdcts/31_FWFLX/freshflux_node.html

The actual data contradicts your statement:

And contrary to media narratives, the science shows warmer temperatures will bring more rain.

In fact the actual measurements show the exact opposite. And all climate models are predicting more global precipitation not less.

As the precession cycle advances, the difference between ocean and land insolation will get less meaning the net water cycle will slow down. Rainfall over land is in long term decline but northern land masses will not be impacted as much as southern and central land masses.

RickWill
Reply to  RickWill
January 4, 2022 10:27 pm

This is the CMIP6 all model mean for precipitation:
http://climexp.knmi.nl/data/icmip6_pr_mon_modmean_ssp585_0-360E_-90-90N_n_su_1980:2030.png
It clearly shows the models are predicting rising precipitation, which is not happening because land and ocean temperatures will move a little closer together as the precession cycle advances. That slows down the net water cycle resulting in lower land precipitation. The ocean temperature warming up is slowing down evaporation as more ocean surface reaches the 30C limit and the ocean shutters go up to reduce surface insolation and evaporation rate.

Last edited 6 months ago by RickWill
Reply to  RickWill
January 5, 2022 7:04 am

You are really twisting things weirdly by mis-applying data. There is no contradiction at at all.

The ITCZ moves towards the hemisphere with more seasonal summer heating. ALL monsoons are driven by land ocean heat contrasts. In summer when the land warms faster than the ocean, ocean moisture is drawn inland.

All supporting my contention “ the science shows warmer temperatures will bring more rain.”

RickWill
Reply to  Jim Steele
January 5, 2022 1:26 pm

ALL monsoons are driven by land ocean heat contrasts. 

No – the convective cloud that forms over open oceans is a temperature limiting process. It is not dependent on the influence of land masses. Convective potential can form thousands of kilometres from any land as the ocean surface warms and the atmospheric water column exceeds 30mm.
https://earth.nullschool.net/#current/wind/surface/level/overlay=cape/orthographic=-294.28,-18.25,375/loc=65.367,-15.661

All oceans regulate to 30C maximum surface temperature by the process of local convective instability:
comment image

Reply to  RickWill
January 5, 2022 1:50 pm

It is senseless to continue responding to you as you deflect to irrelevant responses each and every time. Ridiculous!

Reply to  RickWill
January 5, 2022 9:12 am

You also assume too much from a conflated data set that “global river runoff has declined over the last 50 years”

You need to examine river runoff from a regional perspectives. How do dfferent continents differ in runoff, how do east coasts and wests coasts differ

La Nina’ cause more rainfall over land due to asian monsoons. Less over over the oceans. Pacific Decadal Oscillation has an impact

Take into account of the facdt that 13% of the landmasses are endorheic basins with no outlets to the sea. In 2010 heavy rainfall over Australia’s endorheic basins caused total sea level to fall by 7 mm

RickWill
Reply to  Jim Steele
January 5, 2022 1:33 pm

You need to examine river runoff from a regional perspectives.

The global values provided in those papers are the summation of extensive measurements over all the major river basins. They are the result of extensive measuring networks. Are you claiming they are wrong?

Also all climate models are wrongly predicting precipitation will increase. So you also agree with their prognosis rather than contradict it. The measured data contradicts your conclusion as well was the output of climate models.

Reply to  RickWill
January 5, 2022 1:47 pm

RickWill, Your replies are none-sensical and defensive.

I said: “You need to examine river runoff from a regional perspectives.”

and you go off on another deflection

RickWill
Reply to  Jim Steele
January 5, 2022 6:46 pm

Jim Steele – You make a claim that precipitation is increasing. I show you carefully measured and collated data from two independent sources that show that precipitation is declining globally and you conclude I am deflecting?

The papers I linked to show that the decline is not universal but, on average, over the global land masses precipitation is in a declining trend.

Then you make the absurd suggestion that I should cherry pick the data that shows some regions have increasing precipitation so it agrees with your conclusion!

Reply to  RickWill
January 5, 2022 8:47 pm

Rick, You are obsessed with trying to fit what I said into your theories. You are so blinded you failed to understand what I presented. But get this through your thick skull. NEVER did I make the claim that global “ precipitation is increasing” . You keep making that up to create an argument and push your notions.



marlene
January 4, 2022 6:41 pm

Climate change is not man-made and global warming doesn’t exist. We should not be forced to overwrite investors’ risks, especially when climate laws are intended to bail them out and still leave them with hefty profits.

JCM
January 4, 2022 7:31 pm

Thank you for the very thought provoking presentation. It is a good reminder that drier air should experience greater temperature extremes, both warm and cold. It is also a good reminder that relative pressure variations enhance mixing.

Most every slide discusses convection or pressure gradients and their effects with moving air and energy (bulk movement of water vapour and sensible heat). This process represents the primary energy dissipation mechanism for Earth by converting net incoming solar into outgoing longwave radiation aloft.

The surface propagated IR properties of OLR are effectively only open in cloudless air and so the most dominant factor of OLR must be transmitted flux density by non radiative means (bulk energy transfer by convection and evaporation/condensation).

In the video we come to the energy flow diagram at around the 5 minute mark with standard up and down arrows borrowed from radiative greenhouse theory. It may be a useful schematic – however, in my view it greatly misrepresents (omits) the turbulent mixing of the boundary layer which transmits energy poleward and aloft.

We can see our atmosphere wrestling with energy by using water vapor visualizations. These are the dynamic processes which work to maximize energy dissipation, minimize radiative perturbation, and maximize entropy within the constraints of thermodynamics and hydrostatic equilibrium. Black areas related to IR optical window mostly, and white areas are water vapour emission mostly.

https://gpm.nasa.gov/education/sites/default/files/videos/Earth%20Observatory%20-%20Water%20Vapor%20Animation.mp4

Earth Observatory - Water Vapor Animation2.gif
Last edited 6 months ago by JCM
Gerard O'Dowd
January 4, 2022 8:53 pm

Jim: Enjoyed reading the transcript of Pressure Systems Part II. Thanks for the clarification on the points about the northward movement of the upper limits of ITCZ over the land masses in Africa and Asia during the summer compared to the Western Hemisphere.

I do think it would be important to clarify and specify the average amount of rain in inches that falls in the American Southwest such as New Mexico during the “monsoon season”. The average rainfall amounts are nothing like in India and South west Asia during monsoon season.

AndyHce
January 5, 2022 2:29 am

Why is there no link to part 1, either here or at the transcript?

Reply to  AndyHce
January 5, 2022 7:05 am

I forgot. Will fix

Reply to  Jim Steele
January 5, 2022 9:03 am

Here is link

HOW PRESSURE SYSTEMS CONTROL THE CLIMATE PART 1 – DECLINE IN EXTREME WEATHER

https://www.youtube.com/watch?v=67ie20cjJxU&t=103s

Tom Abbott
January 5, 2022 4:20 am

The land surface does look like it attracts the ITCZ like a magnet. Very interesting.

Richard Mead
January 9, 2022 8:55 am

Good stuff!

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