Albedo-Warming Potential

[Phoenix]

Perhaps Nico can weigh and explain how to interpret some of the figures on his site. See the attached link...

https://cryospherecomputing.tk/awp-region.html

For the CAB chart on the bottom right, it looks like the annual solar input potential is ~ 2,600 MJ / m2 and the actual input  (if I understand the chart correctly) is ~ 500-600 MJ / m2. This would presumably be net of both albedo reflection and also cloud reflection ??

The charts are depicting actual albedo warming in the CAB as ~ 25% of the ice free potential implying 75% average reflection. I guess if I look at those charts a lot, I should try to know exactly what they mean. There is some distance to be reconciled here. Perhaps estimated cloudiness is the difference?

[sedziobs]

This would presumably be net of both albedo reflection and also cloud reflection ??

The charts are depicting actual albedo warming in the CAB as ~ 25% of the ice free potential implying 75% average reflection. I guess if I look at those charts a lot, I should try to know exactly what they mean. There is some distance to be reconciled here. Perhaps estimated cloudiness is the difference?

Look at the y-axis title: clear sky absorption. Clouds are not factored in, which is why it's called Warming "Potential."

In the CAB, it looks like actual absorption is about 20% of ice free absorption until mid-May, which makes sense for 80% snow-covered ice albedo. Then the decadal values start to diverge as melt pond and open water fractions vary. I suspect that actual summer values are slightly underestimated as a result of albedo assumptions for bare ice and melt ponds.

[oren]

It's a result of an assumption about albedo which is true for part of the season but not for other parts of it. Remember the (excellent) tool is for comparison between years, mainly quantifying the latitude and location of open water and the amount of insolation it can receive.

[Phoenix]

It's a result of an assumption about albedo which is true for part of the season but not for other parts of it. Remember the (excellent) tool is for comparison between years, mainly quantifying the latitude and location of open water and the amount of insolation it can receive.

I see what you are saying. But if the tool is really only useful for accurately quantifying the open water AWP and not the areas which are covered by sea ice, it's not very useful for measuring what's going on in the CAB. 

I appreciate your taking the time. Math helps to drill down to the variables in question.

[igs]

It's a result of an assumption about albedo which is true for part of the season but not for other parts of it. Remember the (excellent) tool is for comparison between years, mainly quantifying the latitude and location of open water and the amount of insolation it can receive.

I see what you are saying. But if the tool is really only useful for accurately quantifying the open water AWP and not the areas which are covered by sea ice, it's not very useful for measuring what's going on in the CAB. 

I appreciate your taking the time. Math helps to drill down to the variables in question.

A potiential does not claim to be a good tool for measuring but to compare seasons which is what @Oren just said and there in fact wouldn't be much useful to add to that.

[oren]

I will add, most years albedo, and cloudiness, average out, and since open water has a much lower albedo than anything else, and is often found in more southern latitudes where insolation is accumulated over a longer season, the tool is quite useful even though it skips some of the details. In a weird year such as this, with both low albedo and low cloudiness especially in the center of the CAB, the comparison misses too much of what makes the year unique, but that does not mean the comparison is not useful or has not been useful in the past.

[sedziobs]

Similarly, Slater's model struggles with this season as well because it knows that compact ice in the CAB has historically not melted by September. That will be true until it isn't. All tools have their limits.

[Phoenix]

I will add, most years albedo, and cloudiness, average out, and since open water has a much lower albedo than anything else, and is often found in more southern latitudes where insolation is accumulated over a longer season, the tool is quite useful even though it skips some of the details. In a weird year such as this, with both low albedo and low cloudiness especially in the center of the CAB, the comparison misses too much of what makes the year unique, but that does not mean the comparison is not useful or has not been useful in the past.

Fair enough. Understanding is enhanced by trying to reconcile seemingly conflicting or ambiguous points. In this case about albedo.

You have made a persuasive case which helps to reconcile the ambiguity. Thank you.

"Tell me I forget, teach me I remember, involve me I learn" ~ Benjamin Franklin

[morganism]

Deep Future Climate on Earth: effects of tectonics, rotation rate, and insolation

https://www.essoar.org/doi/10.1002/essoar.10501348.1

https://www.centauri-dreams.org/2020/12/02/deep-future-the-next-supercontinent/

"We know that Earth’s continents used to be packed into a single large land mass called Pangaea, which is thought to have broken apart about 200 million years ago as tectonic plates shifted. Interestingly, we can expect a remote future in which the continents will have once again come together

"The first, occurring in the modeling in about 200 million years, is a merging of all continents except Antarctica around the north pole, forming the supercontinent ‘Amasia.’

The second: The formation of the supercontinent ‘Aurica,’ as all the continents come together around the equator in about 250 million years. The effects are significantly different. The formation of Amasia around the north pole produces a planet about 3 degrees Celsius cooler than the one resulting from the formation of Aurica around the equator. What happens is that the movement of heat from the equator to both poles is disrupted with all the land around the poles.

With heat not being conveyed as efficiently from equator to pole, the poles become colder and remain covered in ice all year long, reflecting significant heat into space. Amasia, according to Way, produces “a lot more snowfall. You get ice sheets, and you get this very effective ice-albedo feedback, which tends to lower the temperature of the planet.”

You also get lower sea levels in the Amasia scenario, with more water trapped in the ice caps. Less land is available for agriculture in a supercontinent with predominantly snowy conditions."

[kassy]

Tealight posted a thread about the future of his website in The Rest. Since not everyone visits that forum here is the link:
https://forum.arctic-sea-ice.net/index.php/topic,3350.0.html

[gerontocrat]

Good Heavens - no-one has posted on this thread since Dec 2020 (including me).

This year AWP anomaly for the whole Arctic is above the 2010's average but well below recent years.
In the High Arctic seas, AWP anomaly is well below the 2010's average - a really slow start.

It is nearly at the Solstice (9 hours to go), so even with very extreme melt from now it is hard to see AWP anomaly reaching the +ve heights of recent years. This tends to imply the freezing season will not be delayed.

3 seas buck the trend, the Laptev, Baffin Bay and the Barents.

[gerontocrat]

One must not forget Nico Sun's data on the Albedo Warming Potential. It is the Cumulative Anomaly that matters.

The overall AWP cumulative anomaly for the Arctic is well above the 2010's average but well below recent years.

But in the High Arctic seas, AWP cumulative anomaly is below the 2010's average - a really slow year to date and we are 16 days after the solstice,

Now this must mean that the AWP anomaly for the Peripheral Seas is very high, (but Nico does not provide the graph for this). This implies high potential for ocean heating in these seas.
So I had a look at SST's. Another speculation bites the dust?

It is well after the Solstice, so even with very extreme melt from now it is hard to see AWP anomaly reaching the +ve heights of recent years. Add to that a lot of cloudy weather at least in the High Arctic and this lends real support to Friv's statements on the melting thread.

3 seas buck the slow trend on AWP, the Laptev by far the most, Baffin Bay and the Barents.

But sea ice losses from maximum this year are. so far, above average.

click images to enlarge
You gave to click the SST image to see it properly

[gerontocrat]

One must not forget Nico Sun's data on the Albedo Warming Potential, sadly neglected this year (including by me). It is the Cumulative Anomaly that matters.

The overall AWP cumulative anomaly for the Arctic is well above the 2010's average but well below recent years.

But in the High Arctic seas, AWP cumulative anomaly is below the 2010's average - a really slow year to date and we are 2 months after the solstice, i.e just about done for the year.

Add to that a lot of cloudy weather at least in the High Arctic and this lends real support to Friv's statements on the melting thread. It's a double whammy - cloudy cool wather slows down melt that reduces AWP that reduces ocean heating that reduces melt.

The Laptev Region bucked the slow trend on AWP by far the most, for the second year. There is a clear correlation in that region between high AWP and high +ve SST anomalies.

click images to enlarge

[gerontocrat]

Hear we are approaching the Northern Hemisphere summer solstice. One must not forget Nico Sun's data on the Albedo Warming Potential (AWP), sadly neglected again this year (including by me). 

I start with NICO's explanation of what AWP is, and why his Solar radiation graph differs from that usually seen;
https://cryospherecomputing.com/doc.html

[size=9t]The Albedo-Warming Potential (AWP) quantifies the additional ocean warming from a lower ice cover at the poles. These calculations don't include cloud cover, therefore it is called "Warming Potential" and not actual warming. However, over the six-month period weather tends to average out and warm areas correlate well with low ice extent in September. The basis of all calculations is a global surface radiation model and NSIDC Sea Ice Concentration data.

Formula per gridcell
AWP Daily = ((1-SIC) * MJ) + 0.15 * MJ * SIC
AWP Accumulated = sum(AWPdaily)
MJ = incoming surface radiation per square meter
SIC = Sea Ice Concentration

The calculated values are arithmetic averages over the whole maximum possible ice extent (shown in light blue). All lakes and some marginal seas (Baltic Sea, Gulf of St. Lawrence) are not considered because their coastline to total area ratio is too high. Coastline measurement errors introduce just random noise.

The graph shows the solar surface radiation per square meter for different latitudes. Unlike "top of the Atmosphere solar radiation" the high latitudes don't experience the highest surface radiation during peak summer. The low angle of solar radiation in high latitudes means more energy is absorbed by the atmosphere. This energy can also raise the surface temperature but is not relevant for surface albedo: ice vs water.[/size]

I also attach the maximum sea ice extent and solar surface radiation graph used in his calculations for the anomaly calculations.

[gerontocrat]

https://cryospherecomputing.com/NRTawp

The attached graphs show that this year AWP to date is low, due to late onset of melt.
This is especially true in the High Arctic.

This obviously reduces the time avaialble for radiation to be applied to open water, as opposed to ice which is in comparison to water highly reflective. Even in a year such as 2012, with extreme sea ice loss from now to minimum, AWP does not catch up with the years of early melt. However, in the High Arctic 2012 melting was not so late, and the accumulated AWP was high.

Note :-By coincidence Nico Sun defines the High Arctic using the same regions as I do, namely the Kara Sea, Laptev Sea, East Siberian Sea, Chukchi Sea, Beaufort Sea, Canadian Archipelago, Central Arctic.

[gerontocrat]

With the melting season entering into high gear here is a look at the Albedo Warming Potential (AWP) so far this year from https://cryospherecomputing.com/NRTawp

The slow start to sea ice area reduction has put a damper on AWP to date, implying a slow start to ocean warming in the Arctic, especially the High Arctic.

Note the word "Potential" - the AWP is based on all days are sunny days.

click images to enlarge

[be cause]

 Worldview , bit of high Arctic : https://go.nasa.gov/3IQ66PL

 with the pack so extensively fractured with open water in the leads , the sun can take advantage of low albedo without melt ponds . Tilt screen to see how 'grey' the image becomes . As the sun shines 24/7 at a low angle this is where it is impacting , not beating down on the top of the 'floes' .   
  btw Do floes cease to be floes at a certain size ? They are certainly smaller than in the past .

[gerontocrat]

Data as at 16th June 2023, Nico Sun's graphs at https://cryospherecomputing.com/NRTawp

Overall Arctic AWP is above the 2010's average, but for the High Arctic well below the 2010's average; reflecting that sea ice melt in the Peripheral seas has been quite strong while sea ice melt in the High Arctic has been quite weak. 

click images to enlarge