Guest essay by Robert A Cook, PE
Annually, the President is required to address the nation and report on the State of the Union. Other writers here regularly report on the oceans and El Nino/ENSO conditions, the duration and status of the extended “pause” in global warming we now are enjoying, and the global average satellite temperature anomalies. Thus, let us plan on summarizing, multiplying, dividing, and discussing the status of the world’s remaining sea ice on or about the twenty-second day of each month.
In particular, for the twenty-second of each month, we will calculate and present for discussion:
- that day’s solar radiation level at top of atmosphere (TOA),
- that day’s declination angle (the tilt of the earth’s axis towards or away from the solar plane),
- that day’s average Antarctic and Arctic sea ice area and extents,
- an estimate of the latitude of the edge of that day’s Antarctic and Arctic areas,
- at the edge of the sea ice for that day, estimate the total reflected and absorbed solar radiation into open water and sea ice for a clear day. (This requires an estimate of the sea ice albedo for that day, the solar elevation of the sun for each hour of that day, an estimate of the open ocean water albedo each hour at each solar elevation angle, and an estimate of the atmosphere’s clarity that day, and the air mass attenuating the sun’s energy each hour of that day at that latitude. )
- an estimate of the average additional heat losses each hour on that day from the open ocean and from the sea ice.
Why regularly discuss sea ice area?
Well, with the “pause” now extending 18 years – 3 months, and with every other CAGW prediction regularly failing as CO2 steadily increases, Arctic sea ice loss is just about the only defense left of the CAGW’s basic predictions. It is regularly hyped and used, so you need to know the details of why they think it is important, and the limits to that assumed importance. (Certainly, the CAGW proponents will not tell you of any limitations or constraints Arctic sea ice poses to their theory of Arctic amplification!) Antarctic sea ice, on the other hand, is failing every assumed CAGW result, and is just uniformly ignored. On the other hand, because it disproves the basic CAGW predictions, you need to know the details of Antarctic sea ice, the problems it poses, and the threats it poses.
Why the twenty-second of each month?
It is a convenient and exciting (well, interesting at least) day for almost all of the changes in all areas we need to look at through the year: solar radiation levels, the earth’s declination, the Antarctic and Arctic sea ice minimums and maximum areas.
The summer and winter solstices (longest day and longest night of the year occur on or about the 22 Dec and 22 June each, the fall and spring equinox fall 90 days later on 21-22 March and 21-22 September each year.
The Antarctic sea ice maximum occurs during the two weeks after 22 Sept each year, the Arctic sea ice minimum occurs a few days earlier: now it is averaging 15-20 Sept. The Antarctic sea ice minimum occurs around 22 Feb each year, the Arctic sea ice maximum occurs a the weeks after 22 March.
Solar radiation is not quite as convenient scheduled, but it is at least completely predictable: maximum solar TOA occurs halfway between 22 Dec and Jan 22 each year, solar TOA minimum occurs 5 July, halfway between 22 June and 22 July.
Antarctica first?
I will usually mention Antarctic sea ice first for several reasons.
First, it is almost always ignored by the CAGW press agents because the Antarctic sea ice reflects badly on several of their predictions about the effects of CO2 in particular and global warming in general. As observers of the global warming debate, you need to know what is happening all over, not just what the press agents want you to know, and what they don’t want you to know.
As important as that is, you will find through the next few months just how much more important the Antarctic sea ice area actually is to the world’s heat balance: The much-hyped Arctic amplification is a very real effect. But it does NOT only occur in the limited area of the Arctic (where sea ice has been receding for several decades) but around the unlimited seas and ever-increasing sea ice surrounding the Antarctica. Down south, where the sun is always higher in the sky and the solar energy reflected back into space much greater, sea ice area really does matter. Up north? Not so much almost all of the year.
Equations.
I will not go into a lot of the equations involved in this first report – there is time for that a bit later. They need to be covered, and the constants and variables need to be looked at in detail. Few “facts” you think you know, very few of the “Wikipedia” constants and textbook assumptions about sea ice really are constant, and almost none of the facts about sea ice, albedos, and solar radiation levels that “everybody knows” are, in fact, actually facts that can stand up to close examinations.
Models and constants and equations?
Challenge any item or equation you disagree with or wish to expand upon. I will in general treat any specific equation sourced from common geometry (such as a conversion of area into latitude, or the solar elevation angle calculated for a day-of-year and hour-of-day and latitude as a specific ‘thing”. It is not a model, nor an approximation. At sea level, the sun really is exactly that high in the sky on that hour of that day of the year at that latitude on earth. If you disagree with an equation, cite your source and justify the difference.
Measured data from field research is a bit different. In general, I will not use error bars or approximations nor will I use purely theoretical data or laboratory approximations such as the Fresnel equations for the albedo of water. (Pure water, in a lab, measured in still air from still water with perfectly aligned parallel and perpendicular light waves? Those conditions do not occur around Cape Horn.)
Everywhere possible, I will quote the experimental data for actual measurements taken in the Antarctic and Arctic itself (sea ice albedo, air temperatures, water temperatures, winds and wind direction, sea ice area, cloudiness and direct/indirect radiation levels); or from the measurements of real seas and real winds and real waves in the open ocean (ocean albedo). I will often approximate experimental results (particularly x,y graphs from old pdf files and graphs) with equations and curve-fit lines. Expect this, and offer better approximations as you see fit and as you can. But the original experiment results ARE the data! You can argue with my approximations (models ?) of each experiment, but you cannot disagree with the real world. Equally, each real world experiment has its own limits and its own assumptions. Again, each source will be discussed in detail over time. Each experimental source will be cited as each detailed equation is discussed – and there will be disagreements between measured results from different sources writing in different journals at different times. Where the source article does present a specific equation or approximation of his or her own work, that equation or constant will usually be used “as-written” for that time frame or those conditions. (For example, in 2001, Dr Judith Curry measured Arctic sea ice albedo as 0.823 That value will be used for all sea ice between January and early May. Her data showed a significant decrease in Arctic sea ice albedo between May and early September, and so her reported values will be curve-fit, and used for all Arctic sea ice albedos between those dates. She has no recorded values for albedo between September and January, so the 0.823 value will be assumed valid after September.)
Solar radiation will usually be addressed pretty much as the measured source data was obtained: in terms of direct radiation only under clear skies with typical Arctic conditions at typical arctic latitudes. Diffuse radiation and cloud cover and relative humidity levels are very important, but we need to get through many other things first. Land area and sea ice area will generally use millions of square kilometers as units (abbreviated as Mkm^2) . Angles are usually in degrees.
Your additions and questions about any value are encouraged of course, but –as Willis requires, always cite exactly what item or quote you question and why you feel it needs to be corrected.
I will not take credit for the basic research results discussed here – all of the hardest field work has already been done years before by many people and many teams from many nations and many institutions, nor of the basic equations and fundamentals used each time. Others deserve that credit, and they will be credited as each detail is discussed. I do acknowledge integrating their work together, and am responsible for the results discussed each time in this series.
Enough talk – You are (probably) even less interested than I in philosophical minutia of the differences between models and equations, between predictions and presumptions and projections and forecasts.
22 January 2015, Day-of-Year (DOY) = 22
Antarctic Sea Ice Area (SIA)
The Antarctic sea ice continues to melt as the year progresses towards its summer minimum in late February. The Antarctic sea ice anomaly is still positiver (more sea ice than “normal”) for this day of year. The Antarctic sea ice anomaly is now just under 1 million square kilometers, representing an area of “excess sea ice” about half the size of Greenland. It has been more than 2 standard deviations above normal for almost 2 years now, and January 2015 only continues that trend towards more sea ice.
Cryosphere (Arctic Climate Research at the University of Illinois)
[Note: There are several other reliable labs and institutions reporting daily sea ice areas and extents. Cryosphere at the University of Illinois is unique in reporting both. All SIA and SIA values differ from each other day by day, so for consistency across both poles, I will only use Cryosphere’s values for area. (Cryosphere data is released one day after processing completes, check the day-of-year values very carefully if you download data files.)]
SIA 1979-2008, DOY 22, = 3.102 Mkm^2, Average this date
SIA 2015, DOY 22, = 4.067 Mkm^2, Actual this date
SIA Anomaly, 2015, DOY 22 = 0.965 Mkm^2, Anomaly this date
Percent increase of Antarctic SIA = 31.1% more Antarctic sea ice than normal for this date
Total Antarctic Ice = 14.0 + 1.5 + 4.1 = 19.6 Mkm^2.
Antarctica’s ice now covers a total area of 19.5 Mkm^2 = 14.0 mkm^2 of continental land ice + 1.5 Mkm^2 of permanent shelf ice plus 4.1 Mkm^2 of total sea ice.
The edge of the Antarctic sea ice is at latitude -67.5 south, very close to the Antarctic Circle at -66.5 south latitude.
General Observations: The Antarctic sea ice continues its annual retreat towards the minium sea ice area in late February. The remaining sea ice tends to be very close to the Antarctic land mass. There is a large open area (polynaya) in the Ross Sea region. This represents an area where the Antarctic sea ice creates an open area between the edge of the sea ice and the Antarctic continent mass, which is unusual. Most of the time in most years, the Antarctic sea ice lies right up close to the coastline, with the sea ice touching the coast (grounded on the beaches) called “fast ice”. (It is held fast by the land.)
Antarctic Sunlight, DOY = 22.
Solar radiation at Top of Atmosphere (TOA) = 1405 watt/m^2, this date (whole earth exposure)
Declination Angle = -0.347, Tau (the Day Angle) = 0.36
At the edge of the Antarctic sea ice, at -67.5latitude, sunrise occurs at 02:00 AM, sunset at 22:00 PM.
At noon, at -67.5 latitude, air mass = 1.482; direct sunlight on a perpendicular surface = 1104 watts/m^2
At noon today, peak radiation on the sea surface = 744 watts/m^2 at a 42.4 solar elevation angle
At noon today, Sea Ice albedo = 0.750; 186 watts are absorbed, 558 watts are reflected into space [rev, 2/3/15]
At noon today, Open ocean albedo = 0.043; 712 watts are absorbed, 32 watts are reflected.
Today, this day of year, for every “excess” meter of Antarctic sea ice, you can see that 558 watts/m^2 are reflected back into space (clear day, at noon). And “sunlight” occurs for 20 of the 24 hours down south at latitude -67.5 today.
Arctic Sea Ice Area (SIA)
22 January 2015, Day-of-Year (DOY) = 22
The Arctic sea ice continues to expand towards its spring maximum in late March. As expected, even as every individual day grows longer after the winter solstice on Dec 22, the Arctic continues to lose heat into space. This heat loss is seen as an increase every day in the Arctic sea ice area.
Today’s Arctic sea ice anomaly remains negative at -0.679 Mkm^2. This continues its decade long negative value, and this value continues the steady negative sea ice anomaly started in early 2013 and continued through all of 2014. However, today’s anomaly is significantly smaller than both 2007 and 2012’s record low sea ice anomaly, and it represents an increase in Arctic sea ice area since 2005. (Today’s sea ice area is larger than most days since 2005, though the difference (the anomaly) remains negative with respect to the 1979-2008 mean area.) Today’s Arctic sea ice anomaly remains within 2 standard deviations of the 1979-2008 mean, and that continues a trend begun in 2013 and continued through most the days since.
Today’s Arctic sea ice anomaly is negative, and represents an area of “lost sea ice” roughly half the size of Hudson’s Bay’s 1.6 Mkm^2.
Cryosphere (Arctic Climate Research at the University of Illinois)
SIA 1979-2008, = 13.131 Mkm^2, Average this date
SIA 2015, DOY 22, = 12.453 Mkm^2, Actual this date
SIA Anomaly, 2015, DOY 22 = -0.679 Mkm^2, Anomaly this date
Percent decrease of Arctic SIA = 5.1% less Arctic sea ice than normal for this date
Total Arctic Sea Ice Area = 12.453 Mkm^2
The edge of the Arctic sea ice lies approximately at latitude 72.0 north, well north of the Arctic Circle at latitude 66.5. (This assumes a circular Arctic sea ice cap, centered at the north pole. The actual Arctic sea ice is only roughly circular, and its geometric center lies closer to the Canadian coast than to the Russian coast.)
Arctic Sunlight, DOY = 22.
Solar radiation at Top of Atmosphere (TOA) = 1405 watt/m^2, this date (same as Antarctica)
Declination Angle = -0.347, Tau (the Day Angle) = 0.36 (same as Antarctica)
At the edge of the Arctic sea ice, at latitude 72.0 north, the sun never rises above the horizon.
(Further south, at latitude 70.1 north, the sun just barely nudges the horizon for a few minutes at noon.)
At noon today, air mass = infinity, solar elevation angle = -1.9 degrees
At noon today, peak radiation on the sea surface = 0 watts/m^2 at -1.9 solar elevation angle
At noon today, sea ice albedo = 0.823, but no energy is absorbed
At noon today, open ocean albedo is meaningless.
Today, this day of year, for every “lost” square meter of sea ice, the open Arctic ocean loses more energy from increased long wave radiation from the open ocean water, from increased convection and conduction losses up to the sea surface, and from increased evaporation losses. In all cases, at this latitude at all hours of the day, more energy is lost from the open Arctic Ocean water than from ice-covered Arctic waters.
Today, this day of year, less Arctic sea ice = more heat loss from the Arctic ocean.
Net Planetary Sea Ice Heat Balance (at noon, this day of year).
Arctic sea ice area anomaly x net solar energy absorbed/m^2 – Antarctic sea ice anomaly x net solar energy reflected /m^2
-.679 Mkm^2 x 0.0 watts/m^2 – 0.965 Mkm^2 x 558 watts/m^2 = -538.5 MWatts reflected back into space at noon, thus cooling the planet.
References and Boilerplate.
Arctic Ice Albedo
1. Curry, J.A. and Schramm, J.L.; Applications of SHEBA/FIRE data to evaluation of snow/ice albedo parameterizations; Journal of Geophysical Research, Vol 106, D14, July 2001.
2. Korff, H.C., Gailiun, J.J. and Vonder Haar, T.H; Radiation Measurements Over a Snowfield at an Elevated Site; Department of Atmospheric Science, Colorado State University, January, 1974.
3. Warren, S.G.; Optical properties of Snow; Review of Geophysics and Space Physics, Vol 20, No. 1; Feb 1982
4. Brandt , R.E., Warren, S.G., Worby, A.P., Grenfell, T.C.; Surface Albedo of the Antarctic Sea Ice Zone, September 2005, Link: http://journals.ametsoc.org/doi/pdf/10.1175/JCLI3489.1
5. Perovich, D.K., Grenfell, T.C., Light, B., Hobb, P.V.; Seasonal evolution of the albedo of multiyear Arctic sea ice; Journal of Geophysical Research, Vol 107, C10, 2002.
[My thanks to reader Matt for recommending two additional references: Brandt 2005 for Antarctic sea ice albedo measurements, and a link to Perovich 2002 with additional photos and errors not available in Curry 2001. Both extend Curry’s measurements for the Arctic ice albedo measurements, but both confirm the similarities and helped eliminate an assumed albedo for the Antarctic spring and summer months on my part. Dr Warren confirmed the values used above for yearly Antarctic albedos, and for winter albedo for both poles.]
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RA
Is there a “threshold” latitude near both poles,
above which ice cover decreases heat loss (since more heat is lost from open water, albedo less important) and below which ice cover increases heat loss (due to more insolation with the sun higher in the sky, albedo more important)?
If so what is it approximately?
Thanks.
Good question.
Obviously, we don’t know this year’s results yet, but I will add your recommendation in.
World’s Daily Net Energy Anomaly =
Antarctic sea ice anomaly (Mkm^2) x Net daily Antarctic energy balance/m^2 +
Arctic sea ice anomaly (Mkm^2) x Net daily Arctic energy balance/m^2
Looking back .. For 2014 and 2013, looking only at SW radiation energy gains/m^2
In Sept, Antarctic has 5x the Arctic’s impact.
The edge of the Antarctic sea ice at its maximum receives five times the solar energy that the edge of the Arctic sea ice at minimum does.
October-Nov-Dec-Jan-Feb-March. there are almost no Arctic solar energy gains at all in Oct and March, and zero Nov-Dec-Jan-Feb when the sun is below the horizona the entire month, regardless of Arctic sea ice extents or Arctic sea ice anomalies either positive or negative. The Antarctic dominates completely. The Arctic sea ice is almost continuously in the dark.
April. The arctic begins to dominate in midday, but loses heat overnight if the sea ice anomaly is negative.
May-June-July. The Arctic receives more solar radiation for longer periods of the day than the Antarctic does.
August. Like April, the arctic continues to dominate in midday in early August, but loses heat overnight if the sea ice anomaly is negative. By Aug 22, both Arctic and Antarctic receive the same amount of solar energy.
In the Antarctic data section, should’t ‘SEA’ be ‘SIA’?
Correct. Thank you.
SEA – Solar Elevation Angle (angle of the sun above the horizon at any given hour-of-day)
SIA – Sea Ice Area
SIE – Sea Ice Extent. (15% or more of the ocean is covered by sea ice)
By the way.
When asked directly, the NSIDC told me that they do NOT include fresh water ice (the Great Lakes and inland US rivers) in their Sea Ice Area (nor Sea Ice Extents) numbers for each day. I do not know if the other sea ice agencies (NORSEX, JAXA (Japan) or DMI (Dutch Meteorological Institution) include or exclude fresh water ice.
NSIDC does NOT include the permanent ice shelves around Antarctica or small areas north of Canada is their daily sea ice totals either.
Yes. Now corrected. Thank you.
See the abbreviations above for SEA, SIA, SIE.
An interesting Arctic science observation regarding solar energy is also mentioned here.
Each year when the solar energy drops to 200 W/m2 and below for the first time, cooling occurs suddenly in the oceans/seas.
The illustration below shows what happens over successive years around Iceland soon as 200 W/m2 are reached.
https://imageshack.us/i/0k200wm2sstscoolingp
200 W/m2 is a key ice age value, where if too much of the planets surface near the poles are absorbing equal or less, our inter-glacier climate ends.
This link should work.
Matt G
To confirm your images, if you look at the Iceland’s yearly sea ice plots for their local area, you will see that the dark blue “triangle” you show is the first region around Iceland to freeze up every year, and the last to thaw out each summer.
Both 2003 and 2004 are El Nino years on the MEI.
“The much-hyped Arctic amplification is a very real effect”
I’m possibly wrong, but isn’t (or shouldn’t) that phrase be, “polar amplification”?
Yes. But the CAGW community has to ignore the recent Antarctic sea ice gains to maintain their facade that
1. Arctic Sea Ice loss is caused by Global Warming.
2. Arctic Sea Ice loss is a proof of Global Warming.
3. Arctic Sea Ice loss will contribute to further Global Warming, or even Catastrophic Global Warming.”
The basic Polar Amplification theory (solar radiation will reflect from sea ice, and be absorbed into open ocean waters) is real phenomenon.
The SECOND half of their logic (The extra energy absorbed into the open ocean waters will heat up the water and cause more ice to melt) is NOT correct in all cases at all times of the day under all light conditions every day of the year at every latitude of the world.
See, “how much” extra solar energy is absorbed IS NOT described nor calculated by the CAGW community because it would reveal some very Inconvenient Truths about their assumptions. So we will do those calculations for one day of every month. Now, from today’s sea ice extents, Polar Amplification Theory DOES WORK.
Up north in the Arctic three months of the year.
Down south in the Antarctic latitudes for (roughly) seven months of the year.
And that ominous Antarctic sea ice is increasing every year.
Would I be right in thinking that the shape and position of the ice, as well as its area, would have an effect on albedo?
By way of illustration, would a perfect disc centred on the North Pole have the same albedo as a disc of the same area centred, say, 200 miles south of the North Pole?
Of any approximation that I’ve ever made, I dislike this assumption of a circular “beanie cap” centered over the north pole the least.
But….
Look at this animation of the Arctic sea ice several times. At minimum, that circle of latitude 80 north represents an area just smaller than the record lowest Arctic sea ice (Sept 2012) . The accepted area of the Arctic Ocean is 14.06 Mkm^2, which is also the average area of the Arctic sea ice at maximum.
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticsst_nowcast_anim365d.gif
Can you think of any better approximation? A very few areas are further south (Hudson Bay, Bering Sea, that limited strip to the east of Greenland, the Denmark Strait, a little bit in the St Lawrence River mouth.) The tip of Greenland intruding into the 80th latitude circle is always ice-covered – it will freeze, melt, and reflect solar energy very much like sea ice.
The actual Arctic sea ice tends to be blown away from north Russia and over towards the north coast of Canada. Those north coast islands is the “bulge” where multi-year sea ice tends to accumulate.
So, my approximation will include a few areas where exposed “open ocean” is inside the beanie cap (north of the approximation) like that persistant “wet spot” just beside Svalsbard Island; and omits a few areas where Arctic sea ice is present at latitudes slightly further south (say 73 – 74 degrees) in the late summer when my approximation assumes the edge of the edge is at 76 or 77 degrees.
But, NO Arctic sea ice is south of 71-72 degrees in August-September-October when Arctic sea ice is at its minimum areas. ALL Arctic sea ice in the Bering Sea, Hudson Bay, Kara Sea, Chukchi Sea, south Baffin Bay and Davis Straits is entirely melted by mid-July. So, the presence (or absence) of sea ice earlier in the year does not affect any sea ice calculations later in the year. Its all water. In winter, the land within the approximation is all sea ice. Or ice-covered small islands – which will behave like sea ice in reflecting solar energy.
@RECookPE1978 animation
Wow, look at all that cold water leaking through the Bearing Straits and down the deep basin channel between Greenland and North America! It is exactly what Willis’ ARGO animation shows. The conventional wisdom is that the Bearing Strait is too shallow for that to happen. My own suspicion is that brine rejected saltwater is going down the deep Greenland channel and freshwater runoff is skating through Bearing. Pretty much a thought in progress, but the Arctic is a very “fresh” ocean.
I fully believe the mechanism of Chen and Tung whereby superhaline warm water can be carried to depth. But the reverse should also be true. Zero degree freshwater from the McKenzie river should be able to levitate two degree saltwater over the Bearing Strait.
Same old story nobody wants to hear. The ocean warms the atmosphere, not the other way around. You put an insulator (yes, ice is a solid that blocks convection and evaporation) and the ocean can transmit less energy to the atmosphere. The albedo is lunch money until the Ides anyway.
Albedo is important, but more important are the ocean currents that distribute cold water.
http://www.biomedcentral.com/1471-2148/10/203/figure/F1?highres=y
I think that it’s important to analyse the climatic revolution in the Arctic area and to see in which measure the oceans and the seas determine the climate. I suggest you to take a look here – http://www.arctic-warming.com/?page_id=17. There are many facts about the Arctic and about the warming phenomenon that happened here.
Very well done post. I’ll look forward to the monthly installments, if Anthony allows.
I am personally less interested in the sea-ice, because as far as I am concerned the entire “albedo” question has already been answered, by the behavior of the ice the past ten years. There has been no “death spiral”. There has been no feedback created, where less ice causes less ice. Instead the ice obeys the PDO and AMO, and likely depends on the strength of their cycles. What would be most interesting to study (IMHI) is how the AMO and PDO behaved during the Medieval Warm Period and the Little Ice Age.
One of the best ways for a layman to study the ice is use your own eyes. There are now a number of drifting cameras, and also the visual satellite views. The press seems to lack the time to actually watch the ice, and see what it does, and sometimes makes statements which, if you have been actually watching the ice, are obvious and atrocious balderdash. However you don’t recognize the balderdash as being balderdash unless you’ve been watching, so use your eyes.
In a couple months we will start to get splendid views due to the fact people start to venture out onto the icecap in March. The Russians set up a base where small jets can land, and wealthy explorers cross-country-ski to the Pole. Modern technology allows them post pictures onto Facebook and Twitter on a daily and even hourly basis.
The explorers tend to preach the Alarmist line, as often their funding depends on it, but if you look at their pictures and listen to their comments you can read between the lines. For example, last year the cross-polar-flow piled up huge pressure ridges north of the Canadian Archipelago, and the explorers were muttering about the mini-mountain-ranges they had to clamber over. One fellow who had done a lot of exploring on arctic ice commented “I’ve never seen such pressure ridges before”, and another nicknamed them “crazy ice”. It simply didn’t fit the narrative, which moans and groans, “It’s melting! It’s melting!”
I strongly advise checking out the various explorers, in March. Ignore their politics, because they pull off amazing feats of strength and endurance.
Please provide full study reference for Judith Curry 2001 albedo measurement. I located a 1995 report “Sea-Ice Albedo Climate Feedback Mechanism” which does show a graph indicating albedo around 0.83 derived using a model. However it should be noted that the albedo given is that which would account for snow covered sea ice in winter and may not necessarily reflect summer conditions in Antarctica. This report also shows the albedo decreases to nearly 0.5 for winter months in the Arctic.
Additionally, I located a 2002 report “Seasonal evolution of the albedo of multiyear Arctic sea ice” Perovich et al. which provides direct measurements of summer time albedo in the Arctic indicating lower albedo as expected during warmer months and may be more reflective (no pun intended) of summer conditions in the Antarctic.
Based on these two references, you may need to adjust the numbers in the calculations to better represent seasonal changes.
I noticed that you do not state the day of year 22 for the SIA 1979-2008 average. Is that indeed the average for the 22nd day of January or the average of those years as a whole? I ask only since the values provided after do state day of year. Please clarify.
matt
Valid observations, but – yes, your information is incomplete.
Arctic Ice Albedo
1. Curry, J.A. and Schramm, J.L.; Applications of SHEBA/FIRE data to evaluation of snow/ice albedo parameterizations; Journal of Geophysical Research, Vol 106, D14, July 2001.
2. Korff, H.C.’ Gailiun, J.J. and Vonder Haar, T.H; Radiation Measurements Over a snowfield at an Elevated Site; Department of Atmospheric Science, Colorado State University, January, 1974.
3. Warren, S.G.; Optical properties of Snow; Review of Geophysics and Space Physics, Vol 20, No. 1; Feb 1982.
(Curry has several other reports and articles from her year up across the Arctic sea ice during the SHEBA in-ice experiment, but No. 1 was most valuable because it did NOT require any modeling or approximations. The daily Arctic sea ice albedo was simply measured by her (her team I suppose) and plotted from April 01 through Oct 11. I used the data directly from her plot. (Ice melt started May 9-12 period, and all measurements prior to May 09 are assumed valid back to January 01 (Day-off-year 01). Refreeze was complete by Sept 18-20, and all albedo’s after Sept 21 were again back up to the first-of-year data at 0.823 (She used 0.8228 in this report, I rounded it off to 0.823.)
“Seasonal evolution of the albedo of multiyear Arctic sea ice” Perovich, 2002 reports the same SHEBA experiment that Curry performed. His report is behind a paywall, I will let them two discuss who did what when and why. I have Curry’s plots, and used her results.
[Update. Perovich et al., 2002 “Seasonal evolution of the albedo of multiyear Arctic sea ice” does report on the same SHEBA experiment data as Dr Curry, but Perovich 2002 includes Arctic albedo standard deviation information. It will be added to the reference list.]
My monthly sea ice summaries will use the correct albedo for that day-of-year as it changes through the year. The lowest albedo was 0.386 on DAY = 221 (08-12), but that was an outlier. Curve-fitting through the entire summer shows a better fit of 0.46 on that date. Likewise, she recorded 0.41 on DAY = 208 (07-27) but the smoothed albedo curve passes a little higher on that date at 0.46. (This matches well with your 0.50 for mid-summer.) She reports the melt ponds began to re-freeze on August 12, which we will show marks the beginning of the time of year when the Arctic stops gaining solar energy in open water and begins to lose more heat each day from evaporation, LW radiation, convection and conduction it gains from the sun. Curry’s plot (Figure 1) has no error bars, I will not provide any. Obviously, there are some, and we can discuss those approximations as you see fit. The other articles and references showed no substantive disagreements with Curry’s measurements.
Antarctic sea ice is unanimously reported in all of the few articles and papers that even mention it as cleaner and brighter than Arctic sea ice (no dust, no pollen, no dirt, no carbon soot or particles, no aerosols, less melt water pockets during the melt season); but equally, its albedo has never been measured out on the Antarctic sea ice pack itself. Antarctic sea ice is over 90% first-year ice, and what little sea ice remains from year to year, is trapped up next to the continental rocks in bays and alone the shore. This 5-6% remaining from year-to-year does NOT flow out towards sea, nor is it out away from the continent reflecting solar energy to any great degree. I have used Curry’s 0.823 through the entire year.
Numerically, I will use Curry’s measured sea ice albedo for (for example) day-of-year 206, the area of Arctic and Antarctic sea ice on DOY = 206, find the average latitude for that area of each sea ice pack, and calculate the solar elevation angle for every hour of DOY = 206 at that latitude. From the SEA and latitude, you get the air mass for each HOD, the atmospheric attenuation for that hour, the albedo of the open ocean water for that SEA, and thus how much direct (and indirect or diffuse) solar energy is absorbed and how much is reflected each hour. From air temperature, wet bulb temperature, and wind speed for that latitude for that day-of-year you can estimate the heat transfer film coefficients for each hour for convection and conduction, the latent heat lost through evaporation, and the LW thermal radiation losses out from the ocean surface or ice surface.
The rest is just arithmetic. 8<)
For DOY = 22 (Jan 22 2015) I simply used the data (numbers) directly from the two Cryosphere plots released on that day.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.antarctic.png
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.arctic.png
(Notice that the two plots above will show today’s date and data – NOT the numbers for Jan 22!)
Nothing fancy.
I have digitized their average 2-year plots for Arctic and Antarctic sea ice averages, and have curved-fit their daily average sea ice areas (and the sea ice extents from the other labs) to make it possible to calculate areas, anomalies, and altitudes (etc) for any day-of-year as it becomes convenient) but the we have to wait until the actual day-of-year to make an actual report. Oh well.
Your information is not complete either hence the comment requesting additional information. I saw the title of that Curry report during my search, so first off, thank you for citing as requested, one more PDF to add to the collection. Citation makes it easier for people to check for themselves as is what you would like your readers to do as indicated in the introduction to your post:
“Your additions and questions…are encouraged”
Perovich, no paywall, full PDF link below:
http://scholar.google.ca/scholar_url?url=ftp://ecco2.jpl.nasa.gov/data3/ATN_output/%2Btemp/%2Bseaice/Perovich_2002.pdf.gz&hl=en&sa=X&scisig=AAGBfm0vhqDjNfESZrX0h2Ev9w-mWkBKig&nossl=1&oi=scholarr&ei=nETGVNSVEIawsATy_IKwDA&ved=0CB8QgAMoAjAA
Laine, V. Antarctic Ice Albedo, Temperature and Sea Ice Concentration Trends, 1981-2000, full PDF link below:
https://www.eumetsat.int/website/wcm/idc/idcplg?IdcService=GET_FILE&dDocName=PDF_CONF_P50_S7_10_SILJAMO_P&RevisionSelectionMethod=LatestReleased&Rendition=Web
Brandt et al. Surface Albedo of the Antarctic Sea Ice Zone, September 2005, full text and PDF link on page:
http://journals.ametsoc.org/doi/pdf/10.1175/JCLI3489.1
There were others that came up in the search but I have not had time to read them so will not discuss them.
Stated in your reply:
“Antarctic sea ice is unanimously reported in all of the few articles and papers that even mention it as cleaner and brighter than Arctic sea ice (no dust, no pollen, no dirt, no carbon soot or particles, no aerosols, less melt water pockets during the melt season); but equally, its albedo has never been measured out on the Antarctic sea ice pack itself.”
This is not entirely true with regards to both suspected cleanliness and measurements. “These impurities could be continental dust from the ice-free regions of coastal Antarctica, 83 km away, or (more likely) algae that entered the snow via seawater flooding of the snow/ice interface… There may also have been biological material from seals, penguins, and other birds” (Brandt et al, 2005).
Although Curry et al. (2001) is speaking of the Arctic, she notes in her conclusions, “Fast ice in coastal regions may be associated with lower surface albedos [e.g. Flato and Brown, 1996]. Additionally, regions in the eastern arctic may be exposed to more soot and sediment, which would lower the albedo.”
Stated in your reply:
“all measurements prior to May 09 are assumed valid back to January 01”
OK, so you have assumed that January albedo during winter in the Arctic is the same as the albedo during summer in the Antarctic. Such assumptions in your introduction and the reply are indicated to be unacceptable:
Stated in your post:
“Enough talk – You are (probably) even less interested than I in philosophical minutia of the differences between models and equations, between predictions and presumptions and projections and forecasts.”
Stated in your reply:
“most valuable because it did NOT require any modeling or approximations”
From Figure 1 of Curry et al. (2001), the roughly 0.8 albedo tends to occur prior to the melt season when dry snow cover is present on the sea ice (April-May measurements) and post melt season from freeze up onward (mid-August to end of September). Summer obviously occurred between these two time frames for which Curry took actual measurements, one of which was as low as 0.38. I did not come across any part of the study that classified that measurement as an outlier and thus, that is your opinion. It is a real measurement and just happens to be the lowest collected measurement, that is all. Since January tends to be near the middle of summer for the Antarctic, if Arctic albedo measurements are going to be used for Antarctic albedo then it would follow that mid-summer Arctic albedo measurements should be used in the calculations (ranging from 0.38 at low point to 0.77 collected during the highest melt time in early June). This posting could have been written for a day where a real data point exists rather than relying on the unknown precision of the posters processes. Another curiosity is why the graph of the curve-fitting that has been created is not provided as part of the write-up along with the data set? Anyway, you could simply just use albedo measurements collected by Brandt et al., 2005 during Antarctic summer. The 0.83 albedo also closes in on one of the highest albedos measured in Curry et al., 2001. That is called “cherry picking” data which results in misinformation. Please refrain. If you want to transfer Arctic sea ice albedo or any other data to the Antarctic, please cite references or provide links to the studies that make for such allowances.
Stated in your reply:
“most valuable because it did NOT require any modeling or approximations”
You approximated the 0.83 by using a best fit line or curve-fitting line and, as indicated by your own statement, is unacceptable. There are plenty of data points, choose an appropriate one for the time of year. Also take note of the various types of sea ice that may be present for a given time of year. These various types have different albedo measurements associated with them resulting in varying degrees of absorbed radiation. Instead of the arbitrary reasons for selecting the given day, select a day based on data collected and reported on in real studies.
Please make the necessary corrections in your post.
It should be noted that the Curry study, although they took direct measurements, the purpose was to evaluate different models for sea ice albedo. It seems that, although with margins of error as can be expected, the models are not that far off. Curry does note, “it appears that a simple albedo parameterization tuned to give appropriate results for snow-covered and melting ice can give reasonable results when used in a sea ice model”. Interesting result from the study conducted and indicates that not all models are blatantly wrong or “fudged”.
Stated in your post:
SIA 1979-2008, = 3.102 Mkm^2, Average this date
SIA 2015, DOY 22, = 4.067 Mkm^2, Actual this date
To simplify the question, why do you not state “DOY 22” for the 1979-2008 average but you state it for the value that follows. I do not question that Cryo has reported the data (along with NSIDC, &c.). More of a curiosity in the write up. I am wondering if it is that you are not sure how Cryo calculated the number and so there is a lack of confidence or perhaps some other reason? Please clarify or give reasoning and update your post to that effect so that everyone who reads is clear on the matter.
And here is a link just so that everyone is clear that no one is hiding anything, there is no conspiracy. This article states clearly that antarctic sea ice has been increasing and the arctic decreasing.
https://nsidc.org/cryosphere/sotc/sea_ice.html
More over, recent studies (not going to list them) have indicated that the science community does not completely understand the processes taking place in the Antarctic so putting words in their mouth or incorrectly interpreting studies serves only to make people look foolish and to undermine the hard work of real scientists that yes, get paid for doing their jobs just like you, me or anyone else. It should be noted that one cannot apply the same logic to both the Arctic and Antarctic for the simple reason that the Antarctic has land mass situated at its centre whereas the Arctic does not never mind the sheer size difference between the two, altitude, wind patterns, ocean currents, air, surface water and depth water temperatures and the list goes on even to include particulates ejected by volcanic eruptions for which may settle in these regions and much more.
1A. No. As stated earlier, Perovich only duplicates the data that Curry reported (though it does provide std deviation points for the albedo – which may help later efforts.) Thank you for providing the gzip file.
No. Laine’s data does have Antarctic sea ice albedo values – but they are reported only as a single average albedo for the entire spring and summer. There is no day-to-day information at all. Further, the data of every one of his plots ends in 2001, and the trend of every one of his plots was a sharp increase in Antarctic sea ice albedo – up from 0.63 in the early 1980’s to 0.76 in 2001. Thus, his information is not accurate now on a daily basis for Antarctic sea ice, particularly since the trend for all of the Antarctic sea ice albedo’s in every different region he reported on began increasing substantially in 1992. Every trend was increasing, the last values of single-point averages for albedo were 0.73 – 0.76. Also, his final albedo for 2001 is not that much different than the daily measured values of 0.823 from Curry and Perovich.
Provide measured daily Antarctic sea ice albedo measurements and I will use them. Otherwise, no. Antarctic sea ice albedo will be approximated at 0.823, with the reservations and cautions I already expressed.
2. Stated in your post:
SIA 1979-2008, = 3.102 Mkm^2, Average this date
SIA 2015, DOY 22, = 4.067 Mkm^2, Actual this date
Are you confusing or confounding the two phrases “Average this date” and “Actual this date” ?
I do not see how you can assume the average Arctic sea ice area for day 21-22 is ANYTHING except the reported Cryosphere average area for day 21 or 22. Cryosphere released their information to the public on Jan 22 with those values. You provided one file reportedly from Cryosphere with the same area and anomaly values listed, but your file had a date = 2015.055 for an anomaly of 0.679 – for the Arctic.
The values in your data file were for the ARCTIC sea ice.
The values reported were the values printed on Cryosphere’s plots on Jan 22 for the Antarctic sea ice area on Jan 22, Antarctic sea ice average area for Jan 22, and the Antarctic sea ice anomaly for Jan 22.
Cryosphere has not returned my phone calls asking about this matter. When they reply with verified information, we can decide if you want to talk about day 21 or 22 information. But please, keep the numbers for Arctic and Antarctic separate.
The equations for the solar elevation angle, axial tilt, hour angle, air mass, air attenuation, and thus energy absorbed and energy reflected from two areas of sea ice at any two latitudes across the globe are identical.
The values returned from each equation depend on hour of day and latitude.
Now, tell me why the Antarctic sea ice is going to reflect and absorb heat differently from the Arctic sea ice.
3. You appear to have great objections to sea ice albedo values, apparently assuming for some reason that I will use the same value for every day of the year.
What is your background in statistical process measurement, QA, field measurements, and data trend analysis? When measured data is changing over time, what classes and training do you have in processing and analyzing that changing data?
Keep writing, I need to figure out how better to resolve your concerns.
Brandt et al. Surface Albedo of the Antarctic Sea Ice Zone, September 2005, full text and PDF link on page:
http://journals.ametsoc.org/doi/pdf/10.1175/JCLI3489.1
Brandt 2005 has some good points within it, and needs serious consideration as a primary source of Antarctic sea ice albedo. On the whole, it supports fully the approximation of assigning a winter-month long albedo of 0.823 for sea ice on both poles. It does not contradict Curry’s measurements of Arctic sea ice albedo of 0.823 for direct sunlight (clear Arctic/Antarctic daylight hours) for modestly thick, fully frozen sea ice (> 0.7 thick) even in the antarctic summer “freezing” months of DJF (Dec-Jan-Feb), but does justify a lower value (which is logical) for (snow-covered) Antarctic sea ice during the “melting” months of SON (Sept-Oct-Nov).
to repeat, you have made several good points, and have provided independent validation of the importance of measured sea ice albedo rather than “Wikipedi-accurate” averages. Equally, you have no invalidated the nhumbers assigned, and so we will specifically address all of them separately in Sea Ice 101 – “Reflections on the Albedo of Sea Ice.”