Aerosol reduction effects

[ajouis]

Obviously a lower concentration leads to higher radiation attaining earth, but the aerosols also have a proven effect of seeding clouds, how much could cloud reduction affect the arctic? It does increase even further radiation to the ground, but lowers the air moisture, which could dampen storms, and increase radiations back to space too, especially early on with a still high albedo.

[oren]

I guess this melting season will help us find out, especially if industrial and transportation activity remains depressed for a few more months.

[FrostKing70]

You may want to take a look at the "Global Dimming - The aerosol masking effect"

There's a number of published papers demonstrating that the removal of the aerosol masking effect, AKA global dimming, will result in a rapid increase in global average temperature.  Above our current level, within a short period of time (weeks to months).

[ajouis]

What we know about aerosol reduction
It will probably worsen heatwaves, especially in the northern hemisphere which is bad news if it penetrates into the arctic circle, like with last year’s Siberian and Canadian heatwave, or for arctic centred heatwaves like we had in northern Greenland
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL082269

It can strengthen the jet stream in winter, when localized in eurasia, because of warming, lessening extreme weathers outside the arctic, so probably good news for the refreeze given that most aerosol is concentrated away from the arctic.
https://www.nature.com/articles/s41558-020-0693-4t
There is further evidence that aerosols could inhibit thermal contrast between land and sea, in east Asia, as well as further evidence that they reduce insolation
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015RG000500

In contrast of the decreased surface insolation, aerosols increase air Temperatures, which seems less important on melting ice, but they also are the cause of more stormy events as opposed to light rain, which will have a definite differentiated impact on the melting season, though I cannot guess which, and on the freezing season with probably earlier refreeze due to less storm events but lesser refreeze due to more ubiquitous snow cover. As the study concentrates on a blackspot for aerosols, it will probably be a much lesser impact in the arctic.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JD030758

Finally there is a feedback loop that increases aerosol concentration, stabilizing it in place, along with the atmosphere, with the creation of a heat gradient. It being broken could paradoxically mean more aerosols in the arctic for a little while (so opposite effects to those discussed above) and more chaos in an already volatile weather and climate system.
https://academic.oup.com/nsr/article/4/6/810/4191281
Additionally another feedback loop between reduced precipitation and higher aerosol concentration, also tributary to the same atmospheric stabilization, strengthens the case for increased precipitations and chaos in the system with reduction in aerosol, although locally
https://opensky.ucar.edu/islandora/object/articles%3A7038/datastream/PDF/download/citation.pdf

Overall, simulations tend to agree that its macro effect is additional melt within the arctic
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015GL065504?campaign=wlytk-41855.6211458333
And, warming in various world regions
https://iopscience.iop.org/article/10.1088/1748-9326/ab6b34

Additional links
https://eos.org/editors-vox/intensified-investigations-of-east-asian-aerosols-and-climate
https://ftp.cpc.ncep.noaa.gov/hwang/Papers_pdf/Publication_2007-present/2008_Zhang_JGR.pdf (Could mean a change in moisture repartition in a reduction event if taken along with the feedback article)

[ArcticMelt2]

Strong evidence of the effects of aerosols is how the winters fell on the border of Canada and the United States, in places where hard-to-recover oil and gas are developed.

https://twitter.com/Climatologist49/status/1260400682089082880

Here is the combined change for the January-April period. One part of the globe is different than the rest.

In fact, this is now the only place on the planet where winters have sharply cooled in recent years. This is in full accordance with the fact that Canada and the United States are the only large countries where in recent years oil and gas production has grown by about 2 times.

[bbr2315]

Strong evidence of the effects of aerosols is how the winters fell on the border of Canada and the United States, in places where hard-to-recover oil and gas are developed.

https://twitter.com/Climatologist49/status/1260400682089082880

Here is the combined change for the January-April period. One part of the globe is different than the rest.

In fact, this is now the only place on the planet where winters have sharply cooled in recent years. This is in full accordance with the fact that Canada and the United States are the only large countries where in recent years oil and gas production has grown by about 2 times.

I would strongly disagree with this assertion. While it is true that we have the oil sands etc now being exploited, I think the main cause for the developing "cold pole" over North America is due to the breakdown of the Arctic sea ice. This has caused more entrenched -500MB anomalies to develop over the vicinity of the Canadian Shield, coincident with earlier / later onset of snowcover, which is being primarily driven (again IMO) by NW'erly winds derived from the drop in sea ice in Bering and Chukchi.

[ajouis]

Strong evidence of the effects of aerosols is how the winters fell on the border of Canada and the United States, in places where hard-to-recover oil and gas are developed.

https://twitter.com/Climatologist49/status/1260400682089082880

Here is the combined change for the January-April period. One part of the globe is different than the rest.

In fact, this is now the only place on the planet where winters have sharply cooled in recent years. This is in full accordance with the fact that Canada and the United States are the only large countries where in recent years oil and gas production has grown by about 2 times.

I would challenge your assertion because neither Texas in its permian basin, nor China, is affected the way this spot is, same for more northern Canadian tar sand. I would think that this might be a siberization of the canadian and upper US core, maybe the jet stream or the effect of more seasonal ice on the northern shores but I don’t know

[ArcticMelt2]

I would challenge your assertion because neither Texas in its permian basin, nor China, is affected the way this spot is, same for more northern Canadian tar sand.

Texas has warm winters - even snow is rarely distinguished from North Dakota and Western Canada.

In China, winter is likewise quite warm, and moreover, aerosol emissions have been actively reduced there for the past 10 years:

https://www.atmos-chem-phys.net/18/14095/2018/acp-18-14095-2018.html



And probably the most important point. Sulfur content is different in different types of oil. Most sulfur is in heavy oil from bitumen. The only place where its production is growing is Western Canada. On the contrary, the sulfur content in shale oil is very small - even less than in conventional oil. Shale oil is mainly produced in Texas and North Dakota. The production of conventional oil in the world, on the contrary, has been stable in recent years. Most of the growth in world oil production over the past 10 years has been in Canada and the United States.



So it's almost certain that the cold winters in North America are caused by the increase in heavy oil production in Canada from bitumen sands.

Oil Production in Canada:

[ArcticMelt2]

As I understand it, the highest point on the chart (Hondo Monterey) - this is an area in California.

https://en.wikipedia.org/wiki/Monterey_Formation

Large-scale oil production has never been conducted there.

Therefore, in terms of sulfur content, oil production in Canada is truly unique. The neighboring Maya point is located in Mexico, where production is collapsing, and Arab oil production is on a plateau with OPEC's stiff quotas.

[ajouis]

sulfur emissions in your target region are a fraction of asians ones or even eastern american ones (https://so2.gsfc.nasa.gov), sulfur content in oil is not the sole component of sulfur pollution, so those spots should have even more sustained negative temperature anomalies, even without snow cover. The fact that this is not the case seems to indicate that the aerosol effect is not responsible for that cold spot, just like it isn't for the one in north atlantic. I would again point out that it looks like a siberization, so it would be worth looking into what patterns lead to that particular continental climate

[interstitial]

As stated elsewhere IMO cold spot in canada has more to do with wavy jetstream / reorienting center on greenland rather than north pole. While I am sure aerosols effect the weather I do not think they are as localized as that.

[ArcticMelt2]

While I am sure aerosols effect the weather I do not think they are as localized as that.

Why do you doubt it? Sulfur dioxide is much heavier than air, so it cannot get into the stratosphere without strong explosions or strong heating.

[ArcticMelt2]

sulfur emissions in your target region are a fraction of asians ones or even eastern american ones (https://so2.gsfc.nasa.gov), sulfur content in oil is not the sole component of sulfur pollution, so those spots should have even more sustained negative temperature anomalies, even without snow cover.

I believe that satellites measure the sulfur content in the air only at high altitudes of several kilometers, and do not see the bulk of the emissions at the surface of the Earth. Only a small part of aerosols reaches great heights, so the main cooling effect can be associated with aerosols that are at a minimum height near the source of emissions.

[interstitial]

sulfur emissions in your target region are a fraction of asians ones or even eastern american ones (https://so2.gsfc.nasa.gov), sulfur content in oil is not the sole component of sulfur pollution, so those spots should have even more sustained negative temperature anomalies, even without snow cover.

I believe that satellites measure the sulfur content in the air only at high altitudes of several kilometers, and do not see the bulk of the emissions at the surface of the Earth. Only a small part of aerosols reaches great heights, so the main cooling effect can be associated with aerosols that are at a minimum height near the source of emissions.

sulfur emissions in your target region are a fraction of asians ones or even eastern american ones (https://so2.gsfc.nasa.gov), sulfur content in oil is not the sole component of sulfur pollution, so those spots should have even more sustained negative temperature anomalies, even without snow cover.

I believe that satellites measure the sulfur content in the air only at high altitudes of several kilometers, and do not see the bulk of the emissions at the surface of the Earth. Only a small part of aerosols reaches great heights, so the main cooling effect can be associated with aerosols that are at a minimum height near the source of emissions.

More to learn thanks

[bbr2315]

Comparing to a year like 2012. And any recent year. The Pacific is currently... VERY positive in terms of OLR. The Atlantic has also shifted warmer with the exception of the NW NATL Cold bubble and what looks like its residual impact off the SE US coast.

And to top it off, the Arctic and Siberia are now.... MUCH hotter relatively speaking.

I think this is showing us that a rapid aerosol reduction combined with rapid contrail drop results in much more cloudless sky overall. The resulting amplification has been particularly stark over oceans, and areas with sea ice. It has been amplifying in the other direction in areas that have been able to maintain abnormally late snowcover (few and far between, this year, appear to be Canadian Shield and the Himalayas.

While those limited areas get colder, more and more (indeed, MOST) areas are now amplifying early in the + direction, especially in Northern / Central Siberia, as this year's snow anomalies and OLR map will attest towards.

I wonder if perhaps the stark drop in Chinese aerosols is particularly to blame for the massive +departures over the South China Sea this month? This could also yield especially potent cyclonic activity as we head into autumn as these positives +s accumulate...

[Hefaistos]

...The Pacific is currently... VERY positive in terms of OLR. The Atlantic has also shifted warmer with the exception of the NW NATL Cold bubble and what looks like its residual impact off the SE US coast.
...

Please explain what you mean when you say that the Pacific is VERY positive in terms of outgoing longwave radiation (OLR)!
When I look at attached chart of SST anomalies, I see that the parts of the Pacific have +ve anomalies, but other parts have -ve anomalies. All in all I don't see the case you make.

Also, the Southern Ocean is rather cold.
And as you say, the cold blob in the Atlantic is large.
The Golf stream is also very cold now.

Recent satellite LT data show a large drop in temperatures for March and April.
https://www.woodfortrees.org/plot/uah6/from:2015/plot/rss/from:2015

The jury is still out regarding the effect of diminished aerosols.

[bbr2315]

...The Pacific is currently... VERY positive in terms of OLR. The Atlantic has also shifted warmer with the exception of the NW NATL Cold bubble and what looks like its residual impact off the SE US coast.
...

Please explain what you mean when you say that the Pacific is VERY positive in terms of outgoing longwave radiation (OLR)!
When I look at attached chart of SST anomalies, I see that the parts of the Pacific have +ve anomalies, but other parts have -ve anomalies. All in all I don't see the case you make.

Also, the Southern Ocean is rather cold.
And as you say, the cold blob in the Atlantic is large.
The Golf stream is also very cold now.

Recent satellite LT data show a large drop in temperatures for March and April.
https://www.woodfortrees.org/plot/uah6/from:2015/plot/rss/from:2015

The jury is still out regarding the effect of diminished aerosols.

Look at the map I posted. There is barely any -OLR in the PAC. Maybe 1-2%, a smidgen of neutral, and then the rest is + or ++.

I would think the impact of contrails on the SHEM is less relevant / severe and also the SHEM itself is less relevant to our weather in the NHEM. RE: contrails / aerosols, while the North Pole is bathed in both, there are not enough destinations around the South Pole to warrant using Antarctica as part of a "Great Circle" route and Antarctica is also the landmass most removed from primary impact of all the factories in the NH (thus perhaps less direct impact and longer lag time to when impact is felt).

[Hefaistos]

BBR, you mean the map you reposted in  reply #5 ?

It shows only land, whereas your argumentation is more about what's happening with sea temperatures.

My map was of the seas, and the temperature data is LT from both land and sea.

We don't need to guess from finding various ad hoc spots in maps, we need to start with the overall picture, and the data which includes as much of earth as possible, i.e. the oceans, and also not only the surface, but the LT as well, as those data are readily available.

Only then, it will be relevant to look at regions or pinpoints.

[Andreas T]

it was possible to plot radiative balance, OLR etc from CERES data
https://forum.arctic-sea-ice.net/index.php/topic,749.msg105484.html#msg105484
maybe this is still available if the data is requested, I have not looked at this since when I posted this

[ArcticMelt2]

https://twitter.com/Climatologist49/status/1268377024738910208

Map shows year-to-date station temperatures in standardized anomalies (standard deviations from 1981-2010). Many stations did not have enough climo data for inclusion. Anchorage, AK, has the 2nd most anomalous negative temp departure globally. #akwx
@AlaskaWx

[Hefaistos]

The map shows regional distribution, but what about quantification? What's the temperature anomaly according to GHCN?
Also noticeable that there is almost no data for SH compared to the NH.

[ajouis]

this map does seem to indicate some warming due to reduction in aerosol (see all of south east Asia and eastern china plus Spain and Italy) if we correlate with industrial output and severity of lockdown, this reduction would have been doubly important because aerosol tend to concentrate in a few places, reduction would have also spread what it still produced out of those spots and into the rest of the atmosphere. However, it is too early to try to spot a global effect or do it systematically because it is too early and some countries have phased out their production later than others, or not at all. I suspect we will see the biggest impact with the economic recession if it sticks. For your hypothesis, articmelt, I think this is inconclusive, one way or another, as this does show in fact an effect opposite to what would be expected for an aerosol producing region in your targeted area but it is still a relatively short time since the oil shock and pandemic, the us didn't have a full lockdown and it loosened environmental emission standards.
I don't know what the anomaly is but I think it would be much more revealing if the spots had the anomaly compared to their local or regional baseline, because that would help understanding local systems in a global context, like aerosols act.

[ajouis]

For the comment synthesizing various papers the link on aerosol reduction and jetstream is broken, here is the good one https://www.nature.com/articles/s41558-020-0693-4?draft=journal&proof=true#change-history