Researchers provide new evidence on the reliability of climate modeling

Columbia researchers provide new evidence on the reliability of climate modeling
Clouds from deep convection over the tropical Pacific ocean, photographed by the space shuttle. Such convective activity drives the Hadley circulation of the atmosphere. Credit: NASA

For decades, scientists studying a key climate phenomenon have been grappling with contradictory data that have threated to undermine confidence in the reliability of climate models overall. A new study, published today in Nature Geoscience, settles that debate with regard to the tropical atmospheric circulation.

The Hadley circulation, or Hadley cell—a worldwide tropical atmospheric circulation pattern that occurs due to uneven solar heating at different latitudes surrounding the equator—causes air around the equator to rise to about 10-15 kilometers, flow poleward (toward the North Pole above the equator, the South Pole below the equator), descend in the subtropics, and then flow back to the equator along the Earth's surface. This circulation is widely studied by because it controls precipitation in the subtropics and also creates a region called the intertropical convergence zone, producing a band of major, highly-precipitative storms.

The study, headed by Rei Chemke, a Columbia Engineering postdoctoral research fellow, together with scientist Lorenzo Polvani, addresses a major discrepancy between climate models and reanalyses regarding potential strengthening or weakening of the Hadley circulation in the Northern Hemisphere as a consequence of anthropogenic emissions.

Historically, climate models have shown a progressive weakening of the Hadley cell in the Northern Hemisphere. Over the past four decades reanalyses, which combine models with observational and , have shown just the opposite—a strengthening of the Hadley circulation in the Northern Hemisphere. Reanalyses provide the best approximation for the state of the atmosphere for scientists and are widely used to ensure that model simulations are functioning properly.

The difference in trends between models and reanalyses poses a problem that goes far beyond whether the Hadley cell is going to weaken or strengthen; the inconsistency itself is a major concern for scientists. Reanalyses are used to validate the reliability of —if the two disagree, that means that either the models or reanalyses are flawed.

Lead author Chemke, a NOAA Climate and Global Change postdoctoral fellow, explains the danger of this situation, "It's a big problem if the models are wrong because we use them to project our climate and send our results to the IPCC (Intergovernmental Panel on Climate Change) and policy makers and so on."

To find the cause of this discrepancy, the scientists looked closely at the various processes that affect circulation, determining that latent heating is the cause of the inconsistency. To understand which data was correct—the models or the reanalyses—they had to compare the systems using a purely observational metric, untainted by any model or simulation. In this case, precipitation served as an observational proxy for latent heating since it is equal to the net latent heating in the atmospheric column. This observational data revealed that the artifact, or flaw, is in the reanalyses—confirming that the model projections for the future climate are, in fact, correct.

The paper's findings support previous conclusions drawn from a variety of models—the Hadley is weakening. That's critical to understand, says Polvani, a professor of applied physics and applied mathematics and of earth and environmental sciences who studies the climate system at the Lamont-Doherty Earth Observatory. "One of the largest climatic signals associated with global warming is the drying of the subtropics, a region that already receives little rainfall," he explained. "The Hadley cell is an important control on subtropical precipitation. Hence, any changes in the strength of the Hadley cell will result in a change in precipitation in that region. This is why it is important to determine if, as a consequence of anthropogenic emission, the Hadley cell will speed up or slow down in the coming decades."

But these findings resonate far beyond the study in question. Resolving contradictory results in scientific research is critical to maintaining accuracy and integrity in the scientific community. Because of this new study, scientists now have added confidence that models are reliable tools for climate predictions.


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More information: Opposite tropical circulation trends in climate models and in reanalyses, Nature Geoscience (2019). DOI: 10.1038/s41561-019-0383-x , https://www.nature.com/articles/s41561-019-0383-x
Journal information: Nature Geoscience

Citation: Researchers provide new evidence on the reliability of climate modeling (2019, June 24) retrieved 18 July 2019 from https://phys.org/news/2019-06-evidence-reliability-climate.html
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Jun 24, 2019
Because of this new study, scientists now have added confidence that models are reliable tools for climate predictions.


No it doesn't. Only actual evidence of their predictions being correct, make them correct. DUH.
Alarmist fraud science rules the day.

Jun 24, 2019
No it doesn't. Only actual evidence of their predictions being correct, make them correct. DUH.


"they had to compare the systems using a purely observational metric, untainted by any model or simulation. In this case, precipitation served as an observational proxy for latent heating since it is equal to the net latent heating in the atmospheric column. This observational data revealed that the artifact, or flaw, is in the reanalyses—confirming that the model projections for the future climate are, in fact, correct."

Jun 24, 2019
If I were to do climate modeling, I would only focus on buffers in the climate science. For example, carbon dioxide is a buffer to wild swings in earth temperature. Or cold water sinks to the bottom of the ocean which causes water to cool off fast in the winter, but warm water floats on the top of the ocean, thus preventing the ocean from continually heating up. Another buffer is that the hotter the earth gets, the more it radiates heat, thus preventing over heating. Using a model to predict the minutia is doomed to fail because the minutia is unknowable. The desert southwest might turn into a jungle at higher CO2 levels, but it is impossible to predict because we cannot predict all the changes to ocean currents.

Jun 24, 2019
coot, you are incompetent to judge the conclusions of even this single article.

Mot only are you incapable of contributing any scientific knowledge
or even processing the continuous flow of data/

updating the accumulating evidence for Humanity's efforts at destabilizing Global Climate processes.

all of you denierbots lack the moral character to accept responsibility for the planetary-wide damage from unnatural anthropocene multitudes of causes.
that are increasing the natural global climate changes to catastrophic levels.

but you , like all the other denierbots, lack any ability to honestly judge your own efforts at anti-scientific fraud!

Jun 24, 2019
Needless to say, all this alarmist caterwauling can safely be ignored as little more than psychological terrorism. There has yet to be a model created that properly considers the Sun-Earth connection, as such the Chicken Littles are just being Chicken Littles.

Jun 24, 2019
okay cantcope

where's your evidence against climate change?
you make some foolish claims that your unsubstantiated "opinions" must(!) be accepted as dogma because?

because?

because you say so!
CASE CLOSED!
don't nobody go discovering any inconvenient facts that might embarrass your speculations.

for instance? you claim that the Earth's atmosphere will prevent any overheating?
the accumulating heat will just "magically" disappear!

Hurrah! for magic!

have you tried to convince our sweltering Venerian neighbors that they are imagining the effects of global over-heating?

cantcope, show your faith as a denierbot is unshakable!
pay their electrical bill for the venerian's air conditioners.

what do you mean you are not yet at the coot's level of looneytoons yet?

okay, start small?
pay my electric bill!
Just send me a few hundred bucks every month would be satisfactory.

&, while empirical evidence may be "impossible" for you?

i'm counting on Real Scientists figuring it out...

Jun 24, 2019
confirming that the model projections for the future climate are, in fact, correct

Ha ha ha haaaa! Nothing could be further from the truth. Even the IPCC (AR5, 2013) inadvertently showed the models are incorrect:

https://www.ipcc....14-3.jpg

The black line is observed temperature. The multi-colored spaghetti of lines above it are climate model projections. All the models show higher temperatures than measured and the difference between projected temperature and measured temperature increases as you go further into the future.

There are numerous reasons why the models are incapable of accurately projecting future temperatures, like not incorporating water vapor (the most potent "greenhouse gas"), unproven premise (CO2 is the main cause of warming), and of course the problem that the climate system is "inherently nonlinear and chaotic" making it extremely difficult (if not impossible) to model.

Jun 24, 2019
I was in Phoenix on Saturday, wasn't even 100 degrees on June 22nd. No global warming there. Still snowing in the Rockies in June, no global warming there either.

Besides, your Chicken Little soothsayer's models have failed miserably so far, that they can predict further out is laughable. They (nor you) don't even understand what they are missing, such is the results of willful ignorance.

BTW, you could solve your high electric bills by placing your head in a bucket of water until it goes dark.


Jun 24, 2019
This observational data revealed that the artifact, or flaw, is in the reanalyses—confirming that the model projections for the future climate are, in fact, correct.


That's a non-sequitur.

Showing the reanalysis to be incorrect does not show the original analysis to be correct. It merely shows the reanalysis to be incorrect. The original model still needs to be validated with a correct reanalysis.

Once they've found where the two models disagree, simply "fixing" the reanalysis to agree on this point does not validate the original model either. That's just retrofitting the models to agree with observation, rather than trying to predict observation from theory, which is going at it backwards. False theories may be fitted to agree with existing data, and then declared correct, until they again fail to predict new observations.


Jun 24, 2019
LMAO.
AGW Cult "science" is shit_tled.

Jun 25, 2019
ROFMLAO i got it now, Antigoracle and his sockpuppets above (aka just himself) is he missing link, That illusive baboon ape to man link no one was ever able to find is actually HIM. Now it all make sense why he is incapable of understanding science !

And looki here, we actually have him on tape ! https://www.youtu...44D2qKOM


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