"Smart" and "Stupid" Questions - Feel Free To Ask

[oren]

I'm not sure I can answer your question, but about your comment on bottom melt - if you check out the Mosaic updates, the graphics posted by uniquorn and Simon show bottom melt has already begun as soon as air temps reached around -5 to 0. I guess to keep the bottom ice from melting in the salty water requires active cooling, and once it's gone the core ice temperatures climb and bottom melt begins.

[nanning]

Phoenix, I think this will help if you know how to use calculus.
http://spiff.rit.edu/classes/phys440/lectures/optd/optd.html

[Phoenix]

I'm not sure I can answer your question, but about your comment on bottom melt - if you check out the Mosaic updates, the graphics posted by uniquorn and Simon show bottom melt has already begun as soon as air temps reached around -5 to 0. I guess to keep the bottom ice from melting in the salty water requires active cooling, and once it's gone the core ice temperatures climb and bottom melt begins.

Hi Oren, I was reading a research article on the connection between open water and extreme bottom melt in the Beaufort in the epic 2007 melt season. It suggests that open water may be a good early season indicator. This could elevate my impression of the importance of JAXA numbers as I perceive that JAXA sensor is better than NSIDC area when it comes to measuring truly open water.

Here is the article if you or anyone else would like to peruse.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008GL034007

[Phoenix]

Phoenix, I think this will help if you know how to use calculus.
http://spiff.rit.edu/classes/phys440/lectures/optd/optd.html

Thanks for the offer nanning. i don't know how to use calculus. Just throwing the question out there to see if anyone else here has wrestled with the issue of depth of penetration of solar into open water.

[kassy]

The ocean is divided into three zones based on depth and light level. The upper 200 meters (656 feet) of the ocean is called the euphotic, or "sunlight," zone. This zone contains the vast majority of commercial fisheries and is home to many protected marine mammals and sea turtles.

Only a small amount of light penetrates beyond this depth.

The zone between 200 meters (656 feet) and 1,000 meters (3,280 feet) is usually referred to as the “twilight” zone, but is officially the dysphotic zone. In this zone, the intensity of light rapidly dissipates as depth increases. Such a minuscule amount of light penetrates beyond a depth of 200 meters that photosynthesis is no longer possible.

https://oceanservice.noaa.gov/facts/light_travel.html

some more details on what controls the depth here:
https://en.wikipedia.org/wiki/Photic_zone

ETA this might be interesting too:
https://nsidc.org/cryosphere/seaice/characteristics/brine_salinity.html

[Phoenix]

Thank you very much Kassy, those links you share corroborate what I found in my poking around these topics yesterday.

An understanding of these factors has the potential to illuminate (pun intended) our understanding of the relationship between bathymetry and Arctic melting processes.

[binntho]

I have a question and an observation for board comment.

Put "penetration depth of solar radiation into the ocean" into google and read the answers.

[Phoenix]

I have a question and an observation for board comment.

Put "penetration depth of solar radiation into the ocean" into google and read the answers.

Perhaps you can enlighten me on the etiquette as to when this thread should be used. 

[oren]

Feel free to ask any relevant question, especially if you are a newbie or rarely post, with no repercussions or snark. If you are an experienced poster google should certainly be your friend as you turn to this thread, but it's not a must. If people don't care to answer, they can simply skip the question.
In any case binntho's implied snark is in the wrong, though his response may be useful in finding the answer.

[Tom_Mazanec]

If I were trying to answer that question I do not think I would have thought to put that eight word query into Google.

[binntho]

Feel free to ask any relevant question, especially if you are a newbie or rarely post, with no repercussions or snark. If you are an experienced poster google should certainly be your friend as you turn to this thread, but it's not a must. If people don't care to answer, they can simply skip the question.
In any case binntho's implied snark is in the wrong, though his response may be useful in finding the answer.

Snarkily implied at that! Usually I enjoy googling for people and distilling what I read and then telling them what conclusions I've come to. It's the educator in me that likes to be stroked every now and then. But ignorant arrogance tends to stroke it the wrong way.

[igs]

But ignorant arrogance tends to stroke it the wrong way.

While I know exactly what you mean and would tend to the same views, it's worth to consider that:


1) We are all ignorant, just not all in the same fields.


2) People with a vast range of knowledge often tend to impatience, anger and sometimes
.   arrogance while the first two can easily make them look arrogant while perhaps they are not.


3) Who denies point 1) above is ignorant and arrogant himself by definition.


This means all is well but it has to be put into account that in relation to all the knowledge that
exists we are all extremely ignorant, not to say stupid. The only difference is that some are a bit more and others a bit less stupid.


BTW anger is NEVER a good approach which does not mean I'm never angry myself but
claiming a RIGHT to be angry is a form of arrogance IM not so H opinion.

[binntho]

Thanks igs for your reminder that ignorance is a shared characteristic, one we all suffer from!

Differently in different areas, of course. And if you've taken courses and read books with names like "How to fake expertise" and "How to write meaningless drivel" and then think that you can apply the methods learned in a forum of people who, while ignorant, are not stupid, does tend to diminish ones rights to polite and considerate treatment.

[blumenkraft]

But ignorant arrogance tends to stroke it the wrong way.

The thread title strongly implies that there is no question too stupid to be asked here.

Literally!

[binntho]

But ignorant arrogance tends to stroke it the wrong way.

The thread title strongly implies that there is no question too stupid to be asked here.

Literally!

Indeed! Absolutely!

Ignorant arrogance or arrogant ignorance is still not a good combination if you expect questions to be answered.

[oren]

Binntho, I thought I made it clear that your snark was in the wrong, and yet you continue with more interpesonal mayhem. Maybe you dislike arrogance, you are certainly arrogant yourself as I am sure you are aware, I can be arrogant too, but that is not the point of this thread. The point is to answer stupid and not stupid questions helpfully, or not answer. If you dislike something, just take a deep breath and don't answer.
I have been lax, more unhelpful posts will be snipped.

[binntho]

Binntho, I thought I made it clear that your snark was in the wrong, and yet you continue with more interpesonal mayhem. Maybe you dislike arrogance, you are certainly arrogant yourself as I am sure you are aware, I can be arrogant too, but that is not the point of this thread. The point is to answer stupid and not stupid questions helpfully, or not answer. If you dislike something, just take a deep breath and don't answer.
I have been lax, more unhelpful posts will be snipped.

Heard and understood!

[Istari]

Is there  a reson that som lakes has  lost the ice but others hasn’t ?
Locking at a few years there defiantly are som randomness in it, but from a small sample there also seams to be some trends

[blumenkraft]

Not an expert, but i could imagine the depth of the pond is a variable to consider. Also the temperature of the surrounding soil. I can even imagine last year's summer temperatures could be represented here?

[oren]

Adding more guesses, it could depend on local obstructions from the south, such as tall trees near the water or some hill. Since the sun is quite low in the spring, any obstructions can delay melt-out. In addition, incoming water in the spring could make a difference, so it would depend on local snow cover and vegetation. Still, lake depth should be the biggest variable.

[binntho]

Difference in depth is probably the biggest reason. I seem to remember reading that the Siberian lakes would freeze several meters down, and if it reached bottom, the ice would slowly contract in the middle, exposing the sides and even enabling a bit of ice-pick fishing.

So a shallow lake will have a lot less ice to melt than a deep lake.

[Sebastian Jones]

From my experience, living close to this kind of environment, I have observed the difference in break up of ponds and lake to be dependent on:

• The thickness of the ice which is dependent on the depth of the water and the presence of ground water flow
• The size of the water body

But mostly it depends on if there is any water flow through the pond.
 Moving water erodes/melts ice much faster than still water.

[Phoenix]

Why have sea levels declined in the most recent measurements? According to NASA, the level declined by 3.5mm from Sep 3, 2019 to Jan 30, 2020. NASA posts the data ~ 120 days in arrears.

https://climate.nasa.gov/vital-signs/sea-level/

I don't see a data thread for SLR. Perhaps I should start one?

[binntho]

Why have sea levels declined in the most recent measurements? According to NASA, the level declined by 3.5mm from Sep 3, 2019 to Jan 30, 2020. NASA posts the data ~ 120 days in arrears.

https://climate.nasa.gov/vital-signs/sea-level/

I don't see a data thread for SLR. Perhaps I should start one?

Sea level changes with amount of precipitation over land, and in this part of the world it's certainly raining a lot these days, with widespread flooding in the Horn. But I think that generally sea level falls in NH summer because of significantly more rainfall in the tropics in summer  than winter.

[oren]

Sea level has always been discussed in "SLR and the social cost of carbon".

[Phoenix]

Why have sea levels declined in the most recent measurements? According to NASA, the level declined by 3.5mm from Sep 3, 2019 to Jan 30, 2020. NASA posts the data ~ 120 days in arrears.

https://climate.nasa.gov/vital-signs/sea-level/

I don't see a data thread for SLR. Perhaps I should start one?

Sea level changes with amount of precipitation over land, and in this part of the world it's certainly raining a lot these days, with widespread flooding in the Horn. But I think that generally sea level falls in NH summer because of significantly more rainfall in the tropics in summer  than winter.

Thanks binntho, your pointing out precipitation led me to this thread.

https://forum.arctic-sea-ice.net/index.php/topic,2876.msg256883.html#msg256883

Apparently, the water content in the northern hemisphere snow pack was very high this winter. So, that looks like largely a timing issue with a lot of that melted snow water heading backing to the ocean.

[SteveMDFP]

But mostly it depends on if there is any water flow through the pond.
 Moving water erodes/melts ice much faster than still water.

Ah, so "still waters run deep."

[Hefaistos]

Corona lockdowns has given massively reduced aerosols.

We expect to get increased warming because less aerosols mean less masking of radiative fluxes.

My question is how this might be detected at the TOA? Will it be a decline of emitted thermal radiation (ETR), e.g. in the form of OLR, or will it be an increase in absorbed solar radiation (ASR)? Or maybe both?

Is there any commonly accepted, scientifically specific expected increase in forcing from aerosol reduction?

[Jump]

A more detailed response to the "June elbow", using the regional NSIDC extent graphs:
* Okhotsk and Bering mostly melt in April and early May.
* Kara and Laptev only start melting in June, the same applies to the Beaufort and Chukchi.
* The landlocked and huge Hudson (forgotten in my earlier response) also starts melting only in June, but then has extensive and predictable losses.
* The only seas losing extent linearly during May are Barents, Greenland and Baffin.

Thus when the main engines die out but the other haven't begun we get the May slowdown, in turn causing the June "elbow".
I get the feeling that if Hudson Bay was taken out of the stats, that elbow could disappear.

Thank you very much for your detailed response, this certainly seems to make sense 😀

[gerontocrat]

A more detailed response to the "June elbow", using the regional NSIDC extent graphs:
* Okhotsk and Bering mostly melt in April and early May.
* Kara and Laptev only start melting in June, the same applies to the Beaufort and Chukchi.
* The landlocked and huge Hudson (forgotten in my earlier response) also starts melting only in June, but then has extensive and predictable losses.
* The only seas losing extent linearly during May are Barents, Greenland and Baffin.

Thus when the main engines die out but the other haven't begun we get the May slowdown, in turn causing the June "elbow".
I get the feeling that if Hudson Bay was taken out of the stats, that elbow could disappear.

Thank you very much for your detailed response, this certainly seems to make sense 😀

Once upon a time, the "* Kara and Laptev only start melting in June,". But as the years rolled by, melt gradually commenced earlier and earlier in May - especially in the Kara. It's that pesky AGW + Polar Amplification wot's dunnit.

ps: You can see how area loss is a leading indicator of melt getting underway in the attached graphs.

[Hefaistos]

Corona lockdowns has given massively reduced aerosols.

We expect to get increased warming because less aerosols mean less masking of radiative fluxes.

My question is how this might be detected at the TOA? Will it be a decline of emitted thermal radiation (ETR), e.g. in the form of OLR, or will it be an increase in absorbed solar radiation (ASR)? Or maybe both?

Is there any commonly accepted, scientifically specific expected increase in forcing from aerosol reduction?

I found the answer for the last question. The IPCC has -0,5 W/sq.m for aerosols.
Some recent research has twice bigger values.

My main question remains unanswered:

How might the massive reduction in aerosols due to corona lockdowns be detected at the TOA? Will it be a decline of emitted thermal radiation (ETR), e.g. in the form of OLR,
or will it be an increase in absorbed solar radiation (ASR)? Or maybe both?

[Glen Koehler]

     I do not have a clear understanding of why a dipole weather pattern over the Arctic is so influential for ice melt.  Here are my guesses:

     1.  High pressure system over the Pacific side of the Arctic creates clear skies and thus higher insolation and thus greater direct exposure of ice surface to solar radiation and thus greater surface melt.

     2.  High pressure over Arctic results in downward moving air mass with warming temperatures reaching the surface.

     3.  Low pressure system paired with high pressure system creates a wind tunnel where the two systems meet.  When oriented to create a strong Pacific to Atlantic wind field, this pulls ice away from the Pacific side and into the Atlantic side where it is closer to export out of the Arctic.
Ice already on the Atlantic side is pushed toward exit via the Barents Sea and out the Fram Strait into rapid melt zones?

      4.  Strong wind field disrupts (what is left) of the Beaufort Gyre nursery for growth of multi-year ice. 

      5.  A strong coherent wind field caused by a dipole creates more Ekman pumping, reduces thermocline layering, and brings heat from deeper levels to the surface?

      6.  Strong winds in any direction move the ice around more, creates more wave action, increases fracturing, and thus more surface area exposed to melt through direct contact with sea water?

      7.  Dipole pattern brings in large volume of warmer air from the lower latitudes into the Arctic, displacing normally colder Arctic air mass?

      8.  Dipole pattern also brings in large volume of moist air that has higher heat carrying capacity?

     These are questions, not statements.  Which of them are accurate?
       

[Glen Koehler]

      From NSIDC September 2012 seasonal summary:
http://nsidc.org/arcticseaicenews/2012/10/poles-apart-a-record-breaking-summer-and-winter/

      'Weather conditions prevailing over the summer of 2012 were quite different from those in 2007.  The summer of 2007 featured unusually high sea level pressure centered north of the Beaufort Sea and Greenland, and unusually low pressure along northern Eurasia, bringing in warm southerly winds along the shores of the East Siberian and Chukchi seas (3 to 5 degrees Celsius, or 5 to 9 degrees Fahrenheit above normal), favoring strong ice melt in these sectors and pushing the ice away from the coast, leaving open water.  The pressure pattern also favored the transport of ice out of the Arctic Ocean and into the North Atlantic through Fram Strait.

     In contrast, the summer of 2012 saw unusually low pressure along the Eurasian coastal seas and extending eastward into the Beaufort sea, most prominently over the East Siberian Sea, with unusually high pressure centered over Greenland and the northern North Atlantic. Air temperatures for summer 2012 were above average over most of the Arctic Ocean (1 to 3 degrees Celsius, or 2 to 5 degrees Fahrenheit), most prominently over the Beaufort Sea, where, because of the pressure pattern, winds were anomalously from the south.

     Melt began two to three weeks earlier than average in the Barents and Kara seas, leading to earlier retreat of sea ice in the region; however, air temperatures remained below average during summer in this region. This points to the impact the continued loss of old, thick ice is having on the ability of the sea ice cover to survive summer melt. Other than the August storm, the pressure pattern in 2012 does not appear to have been as favorable in promoting ice loss as was the case in 2007, and yet a new record low occurred."

(Siberia on left side, Greenland on right, Bering Strait at the bottom)

[Glen Koehler]

       RE June 17 pressure system forecast at http://204.197.0.55/MEmodel/ArcticSnowCover18Z2020-06-17.png

Questions for those with meteorological knowledge: 
      What keeps those multiple adjacent low pressure systems on the Russian side from converging into one big low pressure system? 
   
      Or the multiple high pressure systems on the North American /GIS side from converging into one big high pressure system? 
     
      If either set did converge, would the intensity of the resulting combined system be more or less intense? 
     
      And if both the Russian/low and North American/high groups consolidated, would that create a Titanic dipole?

[Tom_Mazanec]

Here is a “stupid” question:
Why are the 48 contiguous states AGW Houdini?
Whenever I see a map of AGW I see swaths of red, brown and maroon with a white or even pale blue blob in the CONUS. We haven’t had a summer like 1988 since, well, 1988. If it were hotter here it would be easier to convince us of AGW.

[Sebastian Jones]

Here is a “stupid” question:
Why are the 48 contiguous states AGW Houdini?
Whenever I see a map of AGW I see swaths of red, brown and maroon with a white or even pale blue blob in the CONUS. We haven’t had a summer like 1988 since, well, 1988. If it were hotter here it would be easier to convince us of AGW.

Several places are warming faster than the global average, many others are not. A few are even cooler. Aside from ocean currents, changes in polar albedo and the myriad of other factors that can have local effects, changes in agriculture can also have an effect. I read recently, I'll try to find the article, that crop changes in the upper mid west- sort of the Dakotas etc, have changed the evaporations-transpiration rate so dramatically that it feels wetter now even though precipitation has fallen.

[Phoenix]

Here is a “stupid” question:
Why are the 48 contiguous states AGW Houdini?

It's all about the Breitbart / Fox News Christian fundamentalist crowd in the US. There's no Houdini act going on.

[oren]

I have pondered the same thought, although I am not sure if it's just an anecdotal impression. Certainly not true in California. But if there is indeed a persistent cool anomaly of parts of the US, it would have to do with the stuck jet stream and drops of frigid polar air. Not good news to anyone.

[binntho]

Tamino has written extensively on the uneven warming in the contigous United States. A good example is [urlhttps://tamino.wordpress.com/2018/02/20/us-warmhole/]"US Warmhole"[/url]

[grixm]

Anyone know what happened with the "gain" setting on Sentinel Hub / EO browser? It used to be useful to increase contrast in ice that would otherwise just look completely white. But now it only reduces the brightness without increasing contrast/clarity at all. Is there a site with proper gain control for sentinel images?

Examples below. A picture from a month ago from another thread, and then how that same date with approximately the same gain settings looks low.

[johnm33]

'Effects' do your search - visualisation -then 4 icons appear on the right of the dataset line zoom-pin-hide-effects.

[grixm]

'Effects' do your search - visualisation -then 4 icons appear on the right of the dataset line zoom-pin-hide-effects.

I'm saying that I have been using these effects but they do not work anymore. The two images I posted have the same effect settings.

[blumenkraft]

Grixm, this looks like Natural color rendering to me. Try a custom one like

return [B8A*1,B03*1,B02*1]

Click 'custom rendering', then the '</>' button, and paste the monospaced code above. Then the 'Refresh' button.

[grixm]

Grixm, this looks like Natural color rendering to me. Try a custom one like

return [B8A*1,B03*1,B02*1]

Click 'custom rendering', then the '</>' button, and paste the monospaced code above. Then the 'Refresh' button.

Thanks, that gives much better contrast

[The Walrus]

Here is a “stupid” question:
Why are the 48 contiguous states AGW Houdini?
Whenever I see a map of AGW I see swaths of red, brown and maroon with a white or even pale blue blob in the CONUS. We haven’t had a summer like 1988 since, well, 1988. If it were hotter here it would be easier to convince us of AGW.

I have seen many attempts to explain this, but all seem to fall short.  Part of the answer may be that the CONUS is compared to other areas which have experienced more extreme changes due to factors that are apart from the U.S., such as deforestation, pollution, and overdevelopment. 

The CONUS is actually behaving much like the theory of AGW states.  Namely, that warming will be most prevalent during the coldest times and places.  Hence, winters have been warmer, nights have been warmer, and the upper Midwest has experienced the most warming.  On the flip side, summers have been slightly cooler and some areas of the south have experienced overall cooling.  The overall temperature rise is not all the different from the global rise.  If you compare winter temperatures, U.S. temperature have risen higher than the average, but that trend does not extent into the summer.  Many people erroneously claim that AGW will lead to an increase in all temperatures, all the time.  This is not so, and the claim that heat waves will be more frequent and severe has led some to dismiss the entire theory.  IMO, the bigger issue is that the temperature rise has not been detrimental to the whole (California may be the exception).  Most people appreciate the warmer winters and similar summers.  The North has become more bearable and the South has not become unbearable.  The increased precipitation and CO2 fertilization has not hurt either.  This combined effect is expected to continue in the near to middle term.

https://www.cnbc.com/2018/09/17/un-report-shows-climate-change-effect-on-farming.html

[KiwiGriff]

2010-2019: A landmark decade of U.S. billion-dollar weather and climate disasters
Author: Adam B. Smith
January 8, 2020

NOAA’s National Centers for Environmental Information (NCEI) tracks U.S. weather and climate events that have great economic and societal impacts (www.ncdc.noaa.gov/billions). Since 1980, the U.S. has sustained 258* weather and climate disasters where the overall damage costs reached or exceeded $1 billion (including adjustments based on the Consumer Price Index, as of January 2020). The cumulative cost for these 258 events exceeds $1.75 trillion.

During 2019, the U.S. experienced a very active year of weather and climate disasters. In total, the U.S. was impacted by 14 separate billion-dollar disasters including: 3 major inland floods, 8 severe storms, 2 tropical cyclones (Dorian and Imelda), and 1 wildfire event. 2019 also marks the fifth consecutive year (2015-19) in which 10 or more separate billion-dollar disaster events have impacted the U.S.

Over the last several years costly disasters have been particularly destructive. The historic 2019 U.S. inland flooding across many Central states follows the historic 2018 and 2017 Atlantic hurricane and Western wildfire seasons, which set new damage cost records. These disasters have impacted dozens of Eastern, Central, and Western states, in addition to Caribbean territories (i.e., Puerto Rico and the U.S. Virgin Islands).

The number and cost of disasters are increasing over time due to a combination of increased exposure (i.e., values at risk of possible loss), vulnerability (i.e., how much damage does the intensity (wind speed, flood depth) at a location cause) and that climate change is increasing the frequency of some types of extremes that lead to billion-dollar disasters (NCA 2018, Chapter 2).

Number of events
The 14 separate U.S. billion-dollar disasters in 2019 represent the fourth highest total number of events (tied with 2018), following the years 2017 (16), 2011 (16) and 2016 (15). The most recent years of 2019, 2018 and 2017 have each produced more than a dozen billion-dollar disasters to impact the United States—totaling 44 events. This makes a 3-year average of 14.6 billion-dollar disaster events, well above the inflation-adjusted average of 6.5 events per year (1980-2019).

On a slightly longer timeframe, the U.S. has experienced 69 separate billion-dollar disaster events over the last 5 years (2015-2019), an inflation-adjusted average of 13.8 events per year. Over the last 40 years (1980-2019), the years with 10 or more separate billion-dollar disaster events include 1998, 2008, 2011-2012, and 2015-2019.
https://www.climate.gov/news-features/blogs/beyond-data/2010-2019-landmark-decade-us-billion-dollar-weather-and-climate

[The Walrus]

According to data from the experts at Munich Re, the main contribution to the upward trend of the losses caused by natural catastrophes comes from socio-economic/demographic factors such as population growth, ongoing urbanization and increasing values being exposed.  Because of such factors influencing the loss trends a clear attribution of at least part of the effects to global warming is very difficult.

https://www.sciencedirect.com/science/article/pii/S2212094715300347

[oren]

Walrus, here you go yet again in your predecessor Klondike Kat's footsteps. So AGW is not expected to increase summer daytime temperatures? Seriously? As GHGs prevent the escape of energy via the top of the atmosphere, pray tell why this would not affect summers or daytime?
Do you have actual data separating summer and/or daytime temperature statistics from the rest? For the US and globally perhaps? So we can learn if there is indeed such an effect as you describe.
And do you have actual science references that say AGW is not expected to affect summer daytime temperatures?

[blumenkraft]

Thanks, that gives much better contrast

Very welcome. Glad that worked for you.

Be sure to also try 'return [B8A*2,B03*1,B02*1]'. Icy stuff appears in pinkish tones. Melt ponds are easy to spot, they appear in bright blue. The darker the blue, the deeper the melt pond.

I bet there are more treasures hidden in this line of code.

[The Walrus]

Walrus, here you go yet again in your predecessor Klondike Kat's footsteps. So AGW is not expected to increase summer daytime temperatures? Seriously? As GHGs prevent the escape of energy via the top of the atmosphere, pray tell why this would not affect summers or daytime?
Do you have actual data separating summer and/or daytime temperature statistics from the rest? For the US and globally perhaps? So we can learn if there is indeed such an effect as you describe.
And do you have actual science references that say AGW is not expected to affect summer daytime temperatures?

Yes, and I have presented the actual scientific data and references on numerous occasions.  During the daytime in the summer, the increased greenhouse gases act to reduce incoming solar radiation (this is established science).  The GHGs still prevent loss of energy, but since it starting from a lower level, its total effect is less that the loss of incoming energy.