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Have you looked at the North Pole lately?

I

igrowone

Well-known member
Veteran
kickarse said:
Love all the doom and gloom on here

its probably the safest time to be alive, in terms of the planet/? trying to kill us that is
its a fairly calm time in history

if it wasn't for the Socialists trying to fuck us over, with all their garbage "man made" crap
we would be having the time of our lives

but no, its all doom and gloom we all going to DIE from something "extreme"

its fucking laughable
Click to expand...
you're just painting the concerned side with a single brush
it's easy to do
some of us would be good with quicker deployment of low carbon emissions power
and christ!, they are eating coal's lunch a little at a time
all i hear from the other side is weakness - just plain simple fear
see? i can paint as well as you
 
Lyfespan

Lyfespan

Active member
trichrider said:
The bucket list


Correcting historic sea surface temperature measurements reveals a simpler pattern of ocean warming

By Leah Burrows
July 17, 2019



  • View Image


    New research from Harvard corrects decades of sea surface temperature data, solving a long-standing mystery about global climate change.
















Something odd happened in the oceans in the early 20th century. The North Atlantic and Northeast Pacific appeared to warm twice as much as the global average while the Northwest Pacific cooled over several decades.
Atmospheric and oceanic models have had trouble accounting for these differences in temperature changes, leading to a mystery in climate science: why did the oceans warm and cool at such different rates in the early 20th century?
Now, research from Harvard University and the UK’s National Oceanography Centre points to an answer both as mundane as a decimal point truncation and as complicated as global politics. Part history, part climate science, this research corrects decades of data and suggests that ocean warming occurred in a much more homogenous way.
The research is published in Nature.
Humans have been measuring and recording the sea surface temperature for centuries. Sea surface temperatures helped sailors verify their course, find their bearings, and predict stormy weather.
Until the 1960s, most sea surface temperature measurements were taken by dropping a bucket into the ocean and measuring the temperature of the water inside.

A demonstration of the measurement of sea surface temperature from 1947.
The National Oceanic and Atmospheric Administration (NOAA) and the National Science Foundation’s National Center for Atmospheric Research (NCAR) maintains a collection of sea surface temperature readings dating back to the early 19th Century. The database contains more than 155 million observations from fishing, merchant, research and navy ships from all over the world. These observations are vital to understanding changes in ocean surface temperature over time, both natural and anthropogenic.
They are also a statistical nightmare.
How do you compare, for example, the measurements of a British Man-of-War from 1820 to a Japanese fishing vessel from 1920 to a U.S. Navy ship from 1950? How do you know what kind of buckets were used, and how much they were warmed by sunshine or cooled by evaporation while being sampled?
For example, a canvas bucket left on a deck for three minutes under typical weather conditions can cool by 0.5 degrees Celsius more than a wooden bucket measured under the same conditions. Given that global warming during the 20th Century was about 1 degree Celsius, the biases associated with different measurement protocols requires careful accounting.
“There are gigabytes of data in this database and every piece has a quirky story,” said Peter Huybers, Professor of Earth and Planetary Sciences and of Environmental Science and Engineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and senior author of the paper. “The data is rife with peculiarities.”
A lot of research has been done to identify and adjust for these peculiarities. In 2008, for example, researchers found that a 0.3-degree Celsius jump in sea surface temperatures in 1945 was the result of measurements taken from engine room intakes. Even with these corrections, however, the data is far from perfect and there are still unexplained changes in sea surface temperature.
In this research, Huybers and his colleagues proposed a comprehensive approach to correcting the data, using a new statistical technique that compares measurements taken by nearby ships.
“Our approach looks at the differences in sea surface temperature measurements from distinct groups of ships when they pass nearby, within 300 kilometers and two days of one another,” said Duo Chan, a graduate student in the Harvard Graduate School of Arts and Sciences and first author of the paper. “Using this approach, we found 17.8 million near crossings and identified some big biases in some groups.”
The researchers focused on data from 1908 to 1941, broken down by the country of origin of the ship and the “decks,” a term stemming from the fact that marine observations were stored using decks of punch cards. One deck includes observations from both Robert Falcon Scott’s and Ernest Shackleton’s voyages to the Antarctic.
“These data have made a long journey from the original logbooks to the modern archive and difficult choices were made to fit the available information onto punch cards or a manageable number of magnetic tape reels,” said Elizabeth Kent, a co-author from the UK National Oceanography Centre. “We now have both the methods and the computer power to reveal how those choices have affected the data, and also pick out biases due to variations in observing practice by different nations, bringing us closer to the real historical temperatures.”
View Image
This chart shows annual sea surface temperature changes from different datasets in the North Pacific (top) and North Atlantic (bottom). The blue line indicates the corrected data from this research. It shows greater warming in the North Pacific and less warming in the North Atlantic relative to previous estimates.
The researchers found two new key causes of the warming discrepancies in the North Pacific and North Atlantic.
The first had to do with changes in Japanese records. Prior to 1932, most records of sea surface temperature from Japanese vessels in the North Pacific came from fishing vessels. This data, spread across several different decks, was originally recorded in whole-degrees Fahrenheit, then converted to Celsius, and finally rounded to tenths-of-a-degree.
However, in the lead-up to World War II, more and more Japanese readings came from naval ships. These data were stored in a different deck and when the U.S. Air Force digitized the collection, they truncated the data, chopping off the tenths-of-a-degree digits and recording the information in whole-degree Celsius.
Unrecognized effects of truncation largely explain the rapid cooling apparent in foregoing estimate of Pacific sea surface temperatures between 1935 and 1941, said Huybers. After correcting for the bias introduced by truncation, the warming in the Pacific is much more uniform.
While Japanese data holds the key to warming in the Pacific in the early 20th century, it’s German data that plays the most important role in understanding sea surface temperatures in the North Atlantic during the same time.
In the late 1920s, German ships began providing a majority of data in the North Atlantic. Most of these measurements are collected in one deck, which, when compared to nearby measurements, is significantly warmer. When adjusted, the warming in the North Atlantic becomes more gradual.
With these adjustments, the researchers found that rates of warming across the North Pacific and North Atlantic become much more similar and have a warming pattern closer to what would be expected from rising greenhouse gas concentrations. However, discrepancies still remain and the overall rate of warming found in the measurements is still faster than predicted by model simulations.
View Image
Movie of sea surface temperature corrections and the predominant groups reporting sea surface temperatures. The upper panel shows the estimated sea surface temperature correction in degrees Celsius, and the bottom panel indicates the groups that provided the measurements. Groups are typically associated with particular nations and 'decks' of data, respectively indicated by a two-letter code and deck number. GB stands for Great Britain; DE for Germany; NL for the Netherlands; JP for Japan; RU for Russia.
“Remaining mismatches highlight the importance of continuing to explore how the climate has been radiatively forced, the sensitivity of the climate, and its intrinsic variability. At the same time, we need to continue combing through the data---through data science, historical sleuthing, and a good physical understanding of the problem, I bet that additional interesting features will be uncovered,” said Huybers.
This research was co-authored by David I. Berry from the UK National Oceanography Centre. The research was supported by the Harvard Global Institute, the National Science Foundation, and the Natural Environment Research Council.


https://www.seas.harvard.edu/news/2019/07/bucket-list
Click to expand...

but did you hear about the mammoth arctic spring coming from under the ocean, forget which off hand. wonder how this plays into the ever evolving ocean trade currents and such.

earth is but an ice cube in a cup of space, we change directions with every cosmic ray that motivates excitement.
 
Lyfespan

Lyfespan

Active member
kickarse said:
Love all the doom and gloom on here

its probably the safest time to be alive, in terms of the planet/? trying to kill us that is
its a fairly calm time in history

if it wasn't for the Socialists trying to fuck us over, with all their garbage "man made" crap
we would be having the time of our lives

but no, its all doom and gloom we all going to DIE from something "extreme"

its fucking laughable
Click to expand...

we are our own worst enemy yes, and shall remain so till something presents itself as a larger treat to all man kind. Then only reluctant and out of necessity will we unite as a whole, till then, life remains as isolated pockets of condemned humanity.
 
F

Frylock

Lyfespan said:
got to think about it like this. this planet will only sustain life for so long period, regardless of humans or not. Its ever evolving from its circumstances, and is already in motion, we are just ants.

yes, we can slow the affects of melting, but this ice cube is already rolling faster in the drink than anticipated, and its showing. we have pole shifting, increased surface pressure, as well as transplacement of surface weight thereby increased activity in the plates.

its the sad perception that this earth is something that's just here to stay to support human life, even more pathetic to think that you can stop millions of years of evolution. Acceptance of our demise is so hard to fathom, but it will happen. maybe not tomorrow, but again this is a long game.

the public is guarded from these facts to stop hysteria and discord, its management of humans on a larger scale it incredible as well as retarded from a single persons perspective. keep the public busy and entertained.

why do you think we just started a global mission on space travel? india, japan, russia, china and us have major funds and funders in this. why do you think news agencies are telling the public about untold wealth in the cosmos? or fear tactics of impending doom of meteor or asteroids?

we fight amongst ourselves, being distracted from the NWO plan of placation, all the while quietly preparing for the few to try to survive
Click to expand...

'So long a period'.... dude.... of course that is true, i think your perception of time is pretty off though.

To even think about terraforming another planet before trying to take care of our own is ridiculous....

If i were you i would avoid starting posts with 'got to think about it like this' as if you have some deeper grasp of our situation, and then proceed to spew semi-paranoid generic pablum.

:ying:
 
Gry

Gry

Well-known member
Veteran
Lyfespan said:
seems those wholes in the atmosphere aren't as small as we thought or are being told.

especially with the chinese dumping record amounts of refrigerants at 2 very sites:tiphat:
Click to expand...

Speak more of very sites if you would.
 
trichrider

trichrider

Kiss My Ring
Veteran

NEWS 17 July 2019

Space-station cameras reveal how thunderstorms trigger gamma-ray bursts

Mysterious electrical flashes above storm clouds have long puzzled scientists.
Alexandra Witze


d41586-019-02181-8_16936336.jpg
Lightning flashes over Kuwait and Saudi Arabia in this photo taken by astronauts aboard the International Space Station.Credit:NASA/JSC

A cluster of cameras peering down at Earth from the International Space Station has spotted hundreds of gamma-ray flashes going off in the hearts of thunderstorms over the past year. By comparing those enigmatic flashes with lightning rippling through the same storms, space physicists have begun to unravel the decades-old mystery of what causes the high-energy bursts.
The researchers have found that the bursts, known as terrestrial gamma-ray flashes (TGFs), form when powerful electric fields course through the atmosphere, just before a lightning bolt travels along the same path. The charged electrical particles interact with the atmosphere to produce a super-fast flickering of gamma rays, which cannot be seen by the naked eye but are visible to the specialized cameras looking down from the space station.
The instruments have provided the best look yet at the relationship between ordinary lightning and TGFs, which scientists have known about since 1994 but have not been able to explain. “This is a game changer,” says Nikolai Østgaard, a space physicist at the University of Bergen in Norway. He described the findings in a pair of talks at the International Union of Geodesy and Geophysics meeting in Montreal, Canada, on 9 and 12 July.
This insight into how TGFs form comes from the Atmosphere–Space Interactions Monitor (ASIM), a box-shaped set of cameras and sensors built by several European universities and companies and led by the Technical University of Denmark near Copenhagen. ASIM launched to the space station in April 2018. Unlike other missions that study atmospheric electricity, it was designed to study ordinary lightning and TGFs in extraordinary detail at the same time.
Flashes of insight

During its first 10 months of gathering data, ASIM spotted 94 occasions when TGFs and lightning happened very close to one another. More than half followed the same sequence: a weak pulse of light appeared, perhaps after electrically charged particles started moving along a conductive channel in the thunderstorm. Then the TGF burst, spewing gamma rays everywhere. Within a few hundred microseconds, a huge pulse of electric current flowed along that same electrically charged path, making lightning.
The data support the theory that there needs to be a small but strong electric field at the tip of the conductive channel to make a TGF, Østgaard says. Some competing theories had suggested that TGFs form when a thunderstorm builds up a strong, but much larger, electric field in the clouds. “Our results really put a lot of support to the former idea,” Østgaard says. “We have solved the question.”
The new data are “inspiring”, says David Smith, a space physicist at the University of California, Santa Cruz. Joseph Dwyer, a space physicist at the University of New Hampshire in Durham, hopes the observations “will point us in the right direction” to figuring out how TGFs arise.
The ASIM researchers still need to check how its observations compare to other measurements of the same storms, and to see if the relationship it found between TGFs and lightning holds up as it sees more and more of them.
Storm chasers

ASIM is expected to keep working for at least another two years. The team hopes to see many more TGFs during that time. “It’s like being out fishing, and you just have to wait for the big fish,” says Østgaard.
He and his colleagues might even try to get a closer view of these thunderstorm puzzles. ASIM looks down from an altitude of about 400 kilometres above Earth’s surface, and the TGFs occur between about 11 and 13 kilometres above the surface. Østgaard and others are hoping to view the TGFs at close range from an aeroplane flying just above the thunderstorms carrying gamma-ray detectors.
Those research flights could happen as early as 2021 — and provide yet another view of the mystery flashes.

doi: 10.1038/d41586-019-02181-8


https://www.nature.com/articles/d41586-019-02181-8
 
trichrider

trichrider

Kiss My Ring
Veteran
TychoMonolyth said:
[iframe1]L_e1c9SGeJQ[/iframe1]
Click to expand...
i'd never thought about carbon air filters in the grow room capturing CO2. i think i'll turn off the extraction fan and just scrub with the ozone generator, i could/would be wasting my time breathing in and around the grow room.
that could be the reason my phresh filter didn't last as it should, clogged with VOCs and CO2.


still i don't believe CO2 is the culprit/menace/threat/the end.
 
Lyfespan

Lyfespan

Active member
Frylock said:
'So long a period'.... dude.... of course that is true, i think your perception of time is pretty off though.

To even think about terraforming another planet before trying to take care of our own is ridiculous....

If i were you i would avoid starting posts with 'got to think about it like this' as if you have some deeper grasp of our situation, and then proceed to spew semi-paranoid generic pablum.

:ying:
Click to expand...

and working on both this planet and another to move to in time, is unfathomable? just because you or i wont see it doesn't mean it cant happen :tiphat:

im never gonna be you and nor you i, so move past that ego driven statement. I start conversations however i feel, its one of the joys in life :thank you:

I have very profound grasps of the situation, micro and macro. i will always lead more to a debate than most by ways of research, learning, and constantly opposing myopic thinking.

sorry if that offends the way you are used to things
 
Lyfespan

Lyfespan

Active member
trichrider said:
[URL=https://www.icmag.com/ic/]View Image[/URL]
NEWS 17 July 2019

Space-station cameras reveal how thunderstorms trigger gamma-ray bursts

Mysterious electrical flashes above storm clouds have long puzzled scientists.
Alexandra Witze


View Image Lightning flashes over Kuwait and Saudi Arabia in this photo taken by astronauts aboard the International Space Station.Credit:NASA/JSC

A cluster of cameras peering down at Earth from the International Space Station has spotted hundreds of gamma-ray flashes going off in the hearts of thunderstorms over the past year. By comparing those enigmatic flashes with lightning rippling through the same storms, space physicists have begun to unravel the decades-old mystery of what causes the high-energy bursts.
The researchers have found that the bursts, known as terrestrial gamma-ray flashes (TGFs), form when powerful electric fields course through the atmosphere, just before a lightning bolt travels along the same path. The charged electrical particles interact with the atmosphere to produce a super-fast flickering of gamma rays, which cannot be seen by the naked eye but are visible to the specialized cameras looking down from the space station.
The instruments have provided the best look yet at the relationship between ordinary lightning and TGFs, which scientists have known about since 1994 but have not been able to explain. “This is a game changer,” says Nikolai Østgaard, a space physicist at the University of Bergen in Norway. He described the findings in a pair of talks at the International Union of Geodesy and Geophysics meeting in Montreal, Canada, on 9 and 12 July.
This insight into how TGFs form comes from the Atmosphere–Space Interactions Monitor (ASIM), a box-shaped set of cameras and sensors built by several European universities and companies and led by the Technical University of Denmark near Copenhagen. ASIM launched to the space station in April 2018. Unlike other missions that study atmospheric electricity, it was designed to study ordinary lightning and TGFs in extraordinary detail at the same time.
Flashes of insight

During its first 10 months of gathering data, ASIM spotted 94 occasions when TGFs and lightning happened very close to one another. More than half followed the same sequence: a weak pulse of light appeared, perhaps after electrically charged particles started moving along a conductive channel in the thunderstorm. Then the TGF burst, spewing gamma rays everywhere. Within a few hundred microseconds, a huge pulse of electric current flowed along that same electrically charged path, making lightning.
The data support the theory that there needs to be a small but strong electric field at the tip of the conductive channel to make a TGF, Østgaard says. Some competing theories had suggested that TGFs form when a thunderstorm builds up a strong, but much larger, electric field in the clouds. “Our results really put a lot of support to the former idea,” Østgaard says. “We have solved the question.”
The new data are “inspiring”, says David Smith, a space physicist at the University of California, Santa Cruz. Joseph Dwyer, a space physicist at the University of New Hampshire in Durham, hopes the observations “will point us in the right direction” to figuring out how TGFs arise.
The ASIM researchers still need to check how its observations compare to other measurements of the same storms, and to see if the relationship it found between TGFs and lightning holds up as it sees more and more of them.
Storm chasers

ASIM is expected to keep working for at least another two years. The team hopes to see many more TGFs during that time. “It’s like being out fishing, and you just have to wait for the big fish,” says Østgaard.
He and his colleagues might even try to get a closer view of these thunderstorm puzzles. ASIM looks down from an altitude of about 400 kilometres above Earth’s surface, and the TGFs occur between about 11 and 13 kilometres above the surface. Østgaard and others are hoping to view the TGFs at close range from an aeroplane flying just above the thunderstorms carrying gamma-ray detectors.
Those research flights could happen as early as 2021 — and provide yet another view of the mystery flashes.

doi: 10.1038/d41586-019-02181-8


https://www.nature.com/articles/d41586-019-02181-8
Click to expand...

i think these findings and studies are what led to HAARP
 
F

Frylock

Lyfespan said:
and working on both this planet and another to move to in time, is unfathomable? just because you or i wont see it doesn't mean it cant happen :tiphat:

im never gonna be you and nor you i, so move past that ego driven statement. I start conversations however i feel, its one of the joys in life :thank you:

I have very profound grasps of the situation, micro and macro. i will always lead more to a debate than most by ways of research, learning, and constantly opposing myopic thinking.

sorry if that offends the way you are used to things
Click to expand...

Not offended.... just your 'profound grasps' don't come through in your text, a lot of vague generalizations and underestimating others/ overestimating yourself, but i don't want to be a douchebag about it, you seem well intended as am i.

I'm not 'against' the ideas of terraforming Mars, but to me, that isn't something that should really even be on the radar considering how poorly we are doing with the environment here.... where we already have oxygen, water, food, other people.... most everything we need and enjoy.
Can you imagine how bad it would really have to be here on Earth before you would consider moving to Mars??
And then consider moving billions of people there.... it's just so far off.... if we have to act fast Mars is not a viable option.... and by fast i mean thousands of years.
Earth is the #1 option and the #2, #3, #4, #5 options.... yes Mars is 'in play' but wowzers....
The sheer time and resources would be mind boggling.
We are the biggest threats to the earth as it is at the moment, we need to deal with that before worrying about the sun engulfing us.
Anyway, who knows what in the world the future brings.... we may learn how to teleport to different realms or just AI or nuke ourselves to oblivion or.... whatever :biglaugh: :yoinks:
 
trichrider

trichrider

Kiss My Ring
Veteran
Lyfespan said:
i think these findings and studies are what led to HAARP
Click to expand...


you have that just backwards...


HAARP (High Frequency Active Auroral Research Program) began in 1990. Ted Stevens, Republican U.S. senator from Alaska, helped win approval for the facility,[7] and construction began in 1993.

WIKI
/
[FONT=Arial, Helvetica, sans-serif]Atmosphere–Space Interactions Monitor (ASIM)[/FONT]
The ASIM components, originally planned to be completed in 2014, were launched on 2 April 2018 and mounted on the Columbus External Payload Facility on 13 April 2018.

WIKI


ESA astronaut photographed the sprites in 1994, yet the ASIM was not launched into orbit until last year.


..........


https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JA026917


Research Article
An opposite response of the low‐latitude ionosphere at Asian and American sectors during storm recovery phases: drivers from below or above

Chao Xiong
Hermann Lühr
Yosuke Yamazaki



First published: 15 July 2019
https://doi.org/10.1029/2019JA026917

This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1029/2019JA026917


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Abstract

In this study, we focus on the recovery phase of a geomagnetic storm that happened on 6‐11 September 2017. The ground‐based total electron content (TEC) data, as well as the F region in situ electron density, measured by the Swarm satellites show an interesting feature, revealing at low and equatorial latitudes on the dayside ionosphere prominent positive and negative responses at the Asian and American longitudinal sectors, respectively. The global distribution of thermospheric O/N2 ratio measured by GUVI on board the TIMED satellite cannot well explain such longitudinally opposite response of the ionosphere. Comparison between the equatorial electrojet variations from stations at Huancayo in Peru and Davao on the Philippines suggests that the longitudinally opposite ionospheric response should be closely associated with the interplay of E region electrodynamics. By further applying nonmigrating tidal analysis to the ground‐based TEC data, we find that the diurnal components, D0 and DW2, as well as the semidiurnal component SW1 are clearly enhanced over pre‐storm days and persist into the early recovery phase, indicating the possibility of lower atmospheric forcing contributing to the longitudinally opposite response of the ionosphere on 9‐11 September 2017.


full paper here:



https://sci-hub.tw/10.1029/2019JA026917
 
Lyfespan

Lyfespan

Active member
trichrider said:
you have that just backwards...


HAARP (High Frequency Active Auroral Research Program) began in 1990. Ted Stevens, Republican U.S. senator from Alaska, helped win approval for the facility,[7] and construction began in 1993.

WIKI
/
[FONT=Arial, Helvetica, sans-serif]Atmosphere–Space Interactions Monitor (ASIM)[/FONT]
The ASIM components, originally planned to be completed in 2014, were launched on 2 April 2018 and mounted on the Columbus External Payload Facility on 13 April 2018.

WIKI


ESA astronaut photographed the sprites in 1994, yet the ASIM was not launched into orbit until last year.


..........


https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JA026917


Research Article
An opposite response of the low‐latitude ionosphere at Asian and American sectors during storm recovery phases: drivers from below or above

Chao Xiong
Hermann Lühr
Yosuke Yamazaki



First published: 15 July 2019
https://doi.org/10.1029/2019JA026917

This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1029/2019JA026917


[URL=https://agupubs.onlinelibrary.wiley.com/products/pericles/releasedAssets/images/pdf-icon.png]View ImagePDF[/URL]
Tools
Share


Abstract

In this study, we focus on the recovery phase of a geomagnetic storm that happened on 6‐11 September 2017. The ground‐based total electron content (TEC) data, as well as the F region in situ electron density, measured by the Swarm satellites show an interesting feature, revealing at low and equatorial latitudes on the dayside ionosphere prominent positive and negative responses at the Asian and American longitudinal sectors, respectively. The global distribution of thermospheric O/N2 ratio measured by GUVI on board the TIMED satellite cannot well explain such longitudinally opposite response of the ionosphere. Comparison between the equatorial electrojet variations from stations at Huancayo in Peru and Davao on the Philippines suggests that the longitudinally opposite ionospheric response should be closely associated with the interplay of E region electrodynamics. By further applying nonmigrating tidal analysis to the ground‐based TEC data, we find that the diurnal components, D0 and DW2, as well as the semidiurnal component SW1 are clearly enhanced over pre‐storm days and persist into the early recovery phase, indicating the possibility of lower atmospheric forcing contributing to the longitudinally opposite response of the ionosphere on 9‐11 September 2017.


full paper here:



https://sci-hub.tw/10.1029/2019JA026917
Click to expand...

gotch ya their study was more in depth in to one realm of high alt. electrics
 
trichrider

trichrider

Kiss My Ring
Veteran
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083978


High Climate Sensitivity in the Community Earth System Model Version 2 (CESM2)

First published: 16 July 2019
https://doi.org/10.1029/2019GL083978

Abstract

The Community Earth System Model Version 2 (CESM2) has an equilibrium climate sensitivity (ECS) of 5.3 K. ECS is an emergent property of both climate feedbacks and aerosol forcing. The increase in ECS over the previous version (CESM1) is the result of cloud feedbacks. Interim versions of CESM2 had a land model that damped ECS. Part of the ECS change results from evolving the model configuration to reproduce the long‐term trend of global and regional surface temperature over the twentieth century in response to climate forcings. Changes made to reduce sensitivity to aerosols also impacted cloud feedbacks, which significantly influence ECS. CESM2 simulations compare very well to observations of present climate. It is critical to understand whether the high ECS, outside the best estimate range of 1.5–4.5 K, is plausible.


full paper here:


https://sci-hub.tw/https://doi.org/10.1029/2019GL083978


Conclusions

The CESM2 ECS is 5.3K, diagnosed with SOM simulations, an increase of over 1Kfrom CESM1. Higher ECS in CESM2 compared to CESM1 appears to be a consequence of changes to cloud feedbacks and altering ACI to match the 20th century temperature record, which also impacted feedbacks.

CESM2 ECS is similar to the Energy ExascaleEarth System Model version 1 (E3SMv1) [Golaz et al., 2019]. EASMv1 branched offfrom an atmosphere model similar to CAM6d125, though with a different developmenttrajectory thereafter. The land model parameter set used in the intermediate CESM2d125 version (CLM5d125 appears to have damped ECS, likely masking larger cloud feedbacks from CAM6 physicalparameterizations.
Land model changes from CLM4 (CESM1) to CLM5 (CESM2) do notseem to be a significant contributor to the higher climate sensitivity in CESM2, thoughfurther investigation is required to definitely demonstrate this. The atmosphere model inCESM2d125, CAM6d125, has higher cloud feedbacks than CAM5, due to changes in (1)stratiform cloud microphysics, (2) unified turbulence, (3) ice nucleation and (4) convectivechanges increasing LW cloud feedbacks.The final process of developing CESM2 was strongly affected by altering the ACIto adjust to a new emissions dataset, which increased the magnitude of ACI in CESM2.Many of the changes to reduce ACI between CESM2d125 and CESM2 also have affectedcloud feedbacks and ECS, especially rain formation (SB2001) and evaporation (MG2precip)processes and the SO2lifetime. ECS and feedbacks were never explicitly tuned in CESM2, but the ACI was explicitly adjusted downward.This work demonstrates the complex coupling between climate forcing and climatefeedbacks, particularly through the nexus of clouds [Gettelman et al., 2016]. In complexESMs such as CESM2, forcing and feedback are not independent variables, and indeed

Confidential manuscript submitted toGeophysical Research Letters they co-vary [Kiehl, 2007]: processes affecting one will affect the other. The interaction ofspatially varying forcing and feedbacks is a subject for future work.Cloud feedbacks are the cause of increased ECS in CESM2. But the cloud distribution in CESM2 is significantly improved over CESM1 in many ways. CESM2 compares well to observations; better than CESM1 (see supplement), which was already oneof the ‘better’ models in CMIP5 [Knutti et al., 2013]. An ECS of 5.3K would lead to ahigh level of climate change and large impacts. It is imperative that the community workin a multi-model context to understand how plausible such a high ECS is. What scares usis not that the CESM2 ECS is wrong (all models are wrong,Box[1976]), but that it might be right.


:ying:
 
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