Sea Ice 101 – Beware the Ideas of March! (Was the Arctic Maximum “Early” on March 8-9?)

Guest essay by Robert A. Cook, PE

Last week, in my previous article, several critics noted an apparent decline in their Arctic Sea Ice Extents when it dipped back down from a high point over the March 7-8-9 period.

Was this an “early” Arctic Sea Ice Extent maximum? Was today’s Arctic Sea Ice in a truly irreversible decline towards a future catastrophic sea ice level, or was this (yet another!) example of the beginning of the long-postulated Arctic Sea Ice Decline?

Well, the honest answer is –as it always is with “climate” questions and challenges – “We don’t know. Yet. “

First, look at a few plots from the WUWT Sea Ice Page that illustrate this concern.

NSIDC Arctic Sea Ice Extents dipped, then remained “flat” for several days.

N_stddev_timeseries[1]

http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png

 

DMI (Denmark) Arctic Sea Ice Extents: Dipped down, then bounced back up – but only a little bit.

icecover_current_new[1]http://ocean.dmi.dk/arctic/plots/icecover/icecover_current_new.png

NORSEX/NANSEN Arctic Sea Ice Extents: Also dipped down the first week in March, but bounced up a little bit.

ssmi1_ice_ext[1]http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_ext.png

So, were these fears correct? Had the 2015 Arctic Sea Ice reached its yearly maximum “early” … Visibly lower than ANY previous year in the satellite record?

But, let’s look at a long term Arctic sea ice record by a different lab (Cryosphere, University of Illinois). See the Sea Ice Pages, lowest links, for the full northern and southern Cryosphere links to down load any desired data files from 1979 to 2015. http://wattsupwiththat.com/reference-pages/sea-ice-page/

Then, to look at just the days around the sea ice maximum, let’s isolate and plot only those days whose long-term average (1980-2010) are greater than 13.0 million km^2. That curve is plotted below.

clip_image002

So. First, notice that the Arctic Sea Ice “averages” tell a better tale. The maximum occurs over a 10-15 day span, with small dips and bounces even during the maximum peak. So, are bounces unusual?

No. They are so frequent that even a 40 year “average” cannot create a smooth, even curve when plotted! But the “maximum” curve is so broad, so flat across its top that we will not be able to see the 2015’s “Maximum Arctic Sea Ice” Area until well after it has passed us by and has begun its decline.

What is interesting – and may be important, or may be totally a distraction is the “timing” of that maximum point. Look again across the plots above for Sea Ice Extents. Notice how the Arctic Sea Ice extents have been “peaking” later the past 8 to 15 years? Even the Cryosphere average for 1980 – 2010 peaks significantly earlier than it does the past 10 years. So, each day after the spring equinox that the peak sea ice delays causes more and more solar energy to be reflected (lost form the earth’s heat balance back into space) that it was back in earlier “baseline” years.

 

(Notice also that September’s minimum point is also occurring a little bit later (between 15-20 September) than the longer-term average minimum point of 1979-2000.)

Of course, we have no satellite data for Arctic (or Antarctic) sea ice extents before 1979. What happened before? We don’t know. Observations and tales and the (very few) reports back then just do not cover enough area to know. But I recommend tracking BOTH the Arctic maximum AND minimum points against their longer “average” peaks to see what can be pulled out from the plots. It may be interesting.

It may be totally inconsequential.

In short, the small bounces that were seen last week, that were of so great a concern among some WUWT readers, are typical of the Arctic and Antarctic sea ice around the maximum and minimum points. We are so close to last season’s averages and areas that most of 2015 data points overlap the 2014 point for that day. Last year’s late peak may happen again.

Or it may not. As we write this on March 13, the last survey area was March 11, and Arctic sea ice was back higher at a little over 13.0 Mkm^2. Will it go higher yet up towards 13.14 Mkm^2 over the next 10- 15 days? Probably. It has gone higher before. And will get higher again in the future.

Losing the memory of low extent

 

Now – A second, probably more important observation. Will this week’s Arctic Sea Ice “maximum” matter in the future? Will the Arctic Sea Ice declines affect next year’s Arctic Sea Ice area and extents – leading irreversibly to a “decline” or “Arctic Death Spiral” – to capitalize the seriousness of the charge?

You have heard or read the charge if not once, one or two hundred times: Loss of Arctic sea ice means more solar energy is absorbed into the darker Arctic Ocean waters now exposed to the sun. More heat absorbed means the Arctic Ocean heats up more, which melts more Arctic sea ice, which causes yet more solar radiation to be absorbed, which causes yet more ocean water to heat up and melt more sea ice. The next year, the Arctic sea ice begins from a lower extents, and so has less mass to melt during the 24-hour summer days and so there is less thick (second and third-year ) sea ice – which allows even more Arctic sea ice to melt even faster.

The Royal Society of London reviewed that oft-repeated scenario September, 2014. And rejected it.

http://nsidc.org/arcticseaicenews/2015/01/december-ends/

In September of 2014, the Royal Society of London held a workshop focused on the reduction in Arctic sea ice extent. One outcome of this meeting was a greater understanding of the overall trajectory of September ice extent. In a nutshell, it appears that very large departures from the overall downward trend in September extent are unlikely to persist into the following September. If a given September has very low ice extent, strong winter heat loss results in strong ice growth, so that the “memory” of the low ice September ice extent is lost. If a given September has a high ice extent, winter heat loss is more limited, meaning less ice growth. Consequently, while there can be large departures from year to year from the downward linear trend in ice extent (e.g., September 2012 compared to 2014), the natural tendency is for the large departure to dampen out, so that, overall, ice extent stays on the long-term downward trajectory that will eventually lead to seasonally ice free conditions as the Arctic continues to warm in response to rising atmospheric concentrations of Greenhouse gases.

Now, the NSIDC cleverly inserted a computer graphic and paragraph by Julienne Stroeve distorting this conclusion – and their paragraph should be included as well.

clip_image004

Figure 4. This graph shows future projections of September sea ice extent under various future greenhouse gas emission levels. Limiting the warming in 2100 to about 1 to 2 degrees Celsius (2 to 4 degrees Fahrenheit) under the RCP2.6 emission scenario would help to stabilize ice conditions at levels seen today. The RCP8.5 emission scenario (warming by about 4 degrees Celsius 0r 7 degrees Fahrenheit by the end of this century) would result in a seasonally ice-free Arctic by the end of this century. Credit: Julienne Stroeve

So, the NSIDC carefully used model predictions/projections to assure us (the readers) that Arctic sea ice is actually going to disappear in the near future, and all of the gloomy CAGW-assumptions requiring Catastrophic Artificial Constraints will be necessary after all.

But. What did the Royal Society’s actually conclude in September 2014?

Low Arctic Sea Ice extents in Year_1 will not necessarily cause even lower Arctic sea ice extents in Year_2. Low extents in Year_2 will not cause even greater losses in Year_3. (Overall, the Royal Society did accept an assumed total loss of Arctic sea ice some time in the future. ) Sereze’s long-publicized “Arctic Death Spiral” is rejected. Each year’s arctic sea ice may increase (or decrease) from the preceding year’s total independently.

Unusually LOW sea ice extents in September cause extra heat losses in Oct-Nov-Dec, which often causes unusually HIGH sea ice extents in March = the next season’s maximum.

Unusually HIGH sea ice extents in September mean LESS heat loss over the Oct-Nov-Dec-Jan freezing periods, and thus higher than normal sea ice extents the next March-April.

All sea ice that melted one year will definitely re-freeze the next winter. It may be less thick, but it will all re-freeze. Normal sea ice in September indicate normal sea ice extents in March-April the next year will be likely.

So, is this conclusion by the Royal Society backed by the observed Arctic sea ice plots?

clip_image006

Bluntly, looking at the trends over time? Yes, the Royal Society has verified what we here at WUWT have maintained for a while: High Arctic sea ice extents in September cause greater heat loss over the following winter, and unusually high sea ice extents the next March-April.

Now, why does the opposite actually occur?

Unusually high sea ice extents in March-April often lead to unusually low sea ice extents in September.

I am open to comments and observations. Logically – You would assume greater amounts of solar energy are reflected from the increased sea ice area, less heat is absorbed over the Arctic summer months, and so there is less melting in July-August-September, and so the sea ice area in September is expected to be even higher.

But that scenario does not occur.

Unusually “high” Arctic sea ice extents do not often occur in March-April.  Those spikes that have occurred stand out in the record above.  Logically, one would expect the “extra” sea ice to remain in May-June-July, and so reflect extra sunlight otherwise absorbed into the Arctic Ocean, and thus cause unusually high sea ice extents in September.   But “high” March-April sea ice anomalies are almost never followed by a “high” Arctic sea ice minimum in September.

Why do we not see them?

Or, is that the missing “excess” sea ice in March to blame for the “loss of sea ice” so-often blamed as a symptom of “Global Warming”?

Other questions:

clip_image008

The Arctic sea ice anomaly “2 standard deviation” band changes from month to month – going from a high of +/- 1.0 Mkm^2 in September minimum to a substantially lower +/- 0.5 at maximum in March.

But, from 1979 to early 2000, the Arctic sea ice anomaly declined slowly, but remained within 2 std deviations the entire period. It then took a rapid drop, then oscillated widely but always around an “average” lower level of -1.0 Mkm^2 in 2005-2015.

Why did that happen? Why did it drop so much more rapidly – when global average temperatures have NOT dropped, then, why did it oscillate so much around a lower average level?

Odd, this planet we live on.

Advertisements

85 thoughts on “Sea Ice 101 – Beware the Ideas of March! (Was the Arctic Maximum “Early” on March 8-9?)

    • Meanwhile, in the Southern Hemisphere, sea ice trends for 2015 are already ahead of last year’s pace of growth above the 30-year mean. And last year’s sea ice growth was the highest in the entire 36-year satellite record, breaking the previous record from the year before (2013). In fact, 7 of the last 12 months of sea ice trends in Antarctica have set new monthly records of growth. In January (2015), Antarctica’s sea ice was a whopping 44.6% (!) above the 30-year average, the highest-ever sea ice extent recorded for the month in the entire 36 years of data.
      —-
      http://www.ncdc.noaa.gov/sotc/global-snow/2015/1
      “The January Southern Hemisphere sea ice extent was 7.46 million square km (2.88 million square miles), 2.30 million square km (890,000 square miles), or 44.57 percent, above the 1981-2010 average. This was the largest January Southern Hemisphere sea ice extent on record and surpassed the previous record that occurred in 2008 by 580,000 square km (220,000 square miles), which is approximately the size of Madagascar. Seven of the last 12 months have had record large Antarctic sea ice extent.”
      —–
      http://www1.ncdc.noaa.gov/pub/data/cmb/images/global-snow/2014/12/global_seaice.png
      Also, there was more sea ice coverage on the globe in 2013 and 2014 than there was for multiple years during the early 1980s.

      • I saw a -78F in Antarctic on Saturday. Just another late summer afternoon in an upside down world. For some reason the Chicago song Saturday in the park doesn’t seem appropriate there.

    • Funny how that Re-analyzer Globe shows North USA and the Arctic on the opposite side to both be Hot Spots.
      However the Real Time NewSchool Globe shows both areas to be much colder.
      So who do you believe a re-analysis or Real Time.
      I know which one I will go with.
      The Sea Ice did not melt because the temperatures were obove Zero the extent was reduced by wind pressure.

      • Ryan Maue (Weatherbell) suggested caution when looking at Climate Reanalyzer plots. They’re using climatology from the CFS reanalysis model, and subtracting those “normals” from the temperature in the GFS, which is now a much different model than the old frozen version which ran the CFS.

    • Quite warm meaning +3 degrees from average means what? -25F rather than -28F? Still cold enough to [freeze water]. This is not due to temperature, it is due to winds. Winds have kept the ice consolidated and packed together. While sea ice coverage is low, sea ice VOLUME is higher than it has been for the past several years. The ice is thicker, more consolidated, older, and less likely to melt this summer.
      http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAnomalyCurrentV2.1.png

      • Remeber that this chart is generated by a computer model. I believe the WUWT sea ice page states this fact. Their original model actually showed an exponential decrease in the trend, until they could no longer justify it, and had to adjust it to a linear decreasing trend. I tried to post the original version, but failed. So, I don’t know how accurate their representation is compared to the real world data.

    • Wow this looks terrible. How is this created? Hmmm, I go and look at the anomalies currently shown and it looks nothing like this. Oh, Barry you are doing a good job of throwing propaganda disguised as information.

      • I wouldn’t be so sure about that. There is a good chance that the peak will remain at late February. Right around the beginning of February there was a stream of warm moist air that went straight up the middle of the Pacific, and into the Bering Straits region. There was a similar event going on in the Atlantic at the same time, which also funneled a warm moist stream due north. That was certainly part of the reason for the lower sea ice conditions. Then for the last several weeks there has been a westerly air flow crossing above Greenland, and pushing sea ice south into the north Atlantic. This has further changed in the last several days to a strong circular flow that continues east towards Russia, and then back into the Arctic on the Russian side…http://earth.nullschool.net/#current/wind/isobaric/1000hPa/orthographic=0.29,66.40,671
        That looks to be the main reason for the lower state of the ice.

        • Good analysis of the wind changes in late February, early March, thank you. We shall see what happens.
          All of the recent Arctic sea ice maximums have occurred after today’s date. That might happen again.
          Or it may not. Temp’s are still very, very low up there.

    • Barry, are you sure you want to say ” The Arctic is quite warm now”? If so, it does explain a lot. You seem to have ‘warm’ and ‘bloody freezing’ a bit mixed up.

    • Barry,
      Other distinguished commentators,
      This is weather, largely – perhaps some trends. Or not.
      Most will cancel out over thirty, a hundred, a thousand years.
      We have respectable-to-good records since the 1979 satellite year.
      When we can see three thirty-year cycles, let’s scribble an infant hypothesis.
      So – based on good data – we should not get overly dogmatic before the 2070s, at best.
      Auto

    • Sorry. The cause growth inhibition of ice in February was decomposition of ozone in the stratosphere.

  1. If a decline in Arctic sea ice is indicative of the established “reality of anthropogenic climate change beyond any reasonable doubt,” then why is it true that there were several portions of the last 10,000 years in which the Arctic Ocean was actually *ice free* during the summer months? How could this have happened without humans causing it?
    —–
    http://www.sciencedirect.com/science/article/pii/S0277379110003185
    The combined sea ice data suggest that the seasonal Arctic sea ice cover was strongly reduced during most of the early Holocene and there appear to have been periods of ice free summers in the central Arctic Ocean.
    —–
    http://www.sciencedirect.com/science/article/pii/S0277379114001000
    Several studies suggest that the Early Holocene (∼6000–10,000 years BP) experienced less summer-sea ice than at present (e.g. Polyak et al., 2010, Funder et al., 2011 and Müller et al., 2012) … Stranne et al. (2014) show, using numerical modelling, that the sea ice during the Early Holocene potentially could have moved over to a seasonal regime with sea ice-free summers due to the insolation maxima the Earth experienced at that time.
    —–
    http://www.sciencemag.org/content/333/6043/747.full
    Arctic Sea Ice extent during the Holocene Thermal Maximum 8,000 years ago was less than half of the record low 2007 level. [S]ummer sea-ice cover, which reached its Holocene maximum during the LIA, attained its present (~2000) extent at ~4000 years before present. Multiyear sea ice reached a minimum between ~8500 and 6000 years ago, when the limit of year-round sea ice at the coast of Greenland was located ~1000 kilometers to the north of its present position. The subsequent increase in multiyear sea ice culminated during the past 2500 years.
    —–
    http://www.sciencedirect.com/science/article/pii/S0277379113004162
    Arctic Ocean sea ice proxies generally suggest a reduction in sea ice during parts of the early and middle Holocene (∼6000–10,000 years BP) compared to present day conditions. We show that the increased insolation [solar radiation] during EHIM has the potential to push the Arctic Ocean sea ice cover into a regime dominated by seasonal ice, i.e. ice free summers.
    —–
    http://www.biogeosciences.net/9/5391/2012/bg-9-5391-2012.pdf
    Sea surface temperature (Arctic Ocean) between ∼ AD 1885–1935 are warmer by up to 3°C with respect to the average modern temperature at the coring site. For the period ∼ AD 1887–1945, reconstructed sea ice cover values are on average 8.3 months per year which is 1.1 months per year lower than the modern [2012] values. Moreover, reconstructions of sea-surface parameters for the time-period covered by the core show SSTs and SSSs above modern values during positive phases of the PDO: AD 1886–1912; AD 1925–1946 and AD 1979–1996.

    • I don’t have a url handy, but a large number of DMI historical maps were found a few years back and are available online. It’s hard to directly compare them, but they do show extensive melting in some areas, which changes from year to year.
      That said, it is my belief that arctic ice extent is controlled mainly by ocean temp, and since most of the actual weather stations are near the oceans, they are showing excess warming from that.
      I will also note, I believe that for almost all of the year, open water north 65–70 latitude loses more heat to space than it receives, and a death spiral is just impossible (at least under the current orbit).

  2. Meh. Aside from the Barents, which has been slightly below the ave, virtually all of the ‘missing’ ice has been caused by the warm N Pacific this winter preventing ice formation in the Bering and Othotsk Seas. In the Arctic Basin itself, the severe and continued cold has increased the thickness of ice on the Canadian side significantly. No ‘death spiral’ yet.

      • I saw those photos of the sea ice that came ashore in that area. I imagine there might be more bergs than usual in the N. Atlantic this spring.

    • Yes. Most of the ‘missing’ ice is missing from the Sea of Okhotsk and the Bering Sea. This is the key.
      The Sea of Okhotsk is completely separated from the Arctic Ocean and a lack of ice there will have no influence on the ice in the Arctic Ocean.
      Although the Bering Sea is not completely separated from the Arctic Ocean, I suspect it is sufficiently separated to have very little effect on the ice in the Arctic Ocean.

      • J Calvert N(UK)

        Although the Bering Sea is not completely separated from the Arctic Ocean, I suspect it is sufficiently separated to have very little effect on the ice in the Arctic Ocean.

        There is very, very little movement of the surface-floating ice through the narrow Bering Straits. Deep water flow. But very, very little surface movement of ice compared to the total areas involved. And all of this southern ice melts out quickly between April and the end of May.

  3. “Will it go higher yet up towards 13.14 Mkm^2 over the next 10- 15 days? Probably. It has gone higher before. And will get higher again in the future.”
    Probably not with the North Atlantic Oscillation shifting negative.
    “But, from 1979 to early 2000, the Arctic sea ice anomaly declined slowly, but remained within 2 std deviations the entire period. It then took a rapid drop, then oscillated widely but always around an “average” lower level of -1.0 Mkm^2 in 2005-2015.
    Why did that happen? Why did it drop so much more rapidly – ”
    Increases in negative NAO. While increased forcing of the climate increases positive NAO.

  4. It’s rather a distraction, really. Even if Arctic ice is shrinking, all that says is that temperatures are higher in the Northern Hemisphere than they have been during most of the period of observation. But, this is not a subject of contention. Everyone knows that temperatures rose during the last century. The question is why?
    Add to that the fact that Antarctic ice is at record levels, and all you are left with is a muddle of information which is being employed selectively to promote a particular viewpoint.

  5. The clue lies not in the Arctic but Hudson Bay. All previous Ice Ages began glaciation there, not at the North Pole itself. The oceans were still warmer than land and land got to be VERY cold especially the parts furthest from ocean currents.

  6. The albedo of Earth by Graeme L. Stephens et al. (see it on Judith Curry’s site), found that the albedo of earth varies very very little north to south. It appears regulated by clouds, more when there is less ice and vice versa. I believe what Stephens is saying is that even if all the ice did melt, there would be little or no change in the earth’s overall albedo and hence a minor temperature change in the arctic because of the warmer water, but little or none globally.

    • Understood. The Antarctic sea ice – at 58-64 south it is much closer to the equator than the Arctic sea ice up at 72-90 north – will affect total earth albedo more, even in these “equatorial surveys” by satellite.

    • Geoff

      Much of the reduction in ice is not in the Arctic itself but north of Japan where it has been warmer.

      Good find. Yes, and that area completely melts out every year – so, by the time of September’s minimum Arctic sea ice extents, the presence (or absence) of sea ice earlier in the year is meaningless to the September total. No multi-year ice at all.

  7. I have noticed that this year there have been persistant strong northerly winds to the east and west of Greenland, and the ice east of Greenland has been pushed south at a quite high rate all year into the warmer water, presumably causing the ice to melt.
    Could this be one cause of less ice, like the gales in 2012 pushing lots of ice north from the north coast of Russia was a major element of the low ice area that year?

    • Oldseadog

      Could this be one cause of less ice, like the gales in 2012 pushing lots of ice north from the north coast of Russia was a major element of the low ice area that year?

      To be honest, I don’t know. Haven’t tracked enough far-north Atlantic storms long enough to decide.

    • In the old days, before “science” was perverted by politics, the “anomaly” line would have been called an “average” and been about 1C higher in that chart.

    • Chris Hanley, I agree, it is an obsession. I’ve lost interest in it because it’s so transitory. If you think there’s too little ice, just wait six months. If too much, same advice.

  8. Warmist will now have us believe that Ice which is perfectly happy at minus 25˚C melts at minus 23˚C?
    Anyone who regularly watches the Arctic, (which is wonderfully easy on Nullschool Earth) can see that there have been a series of ferocious cyclones north of Iceland this year which have been actually compressing the Sea Ice, or should I say piling it up. There will be a big increase in multi year Ice this year!

    • Charles nelson

      Anyone who regularly watches the Arctic, (which is wonderfully easy on Nullschool Earth) can see that there have been a series of ferocious cyclones north of Iceland this year which have been actually compressing the Sea Ice, or should I say piling it up. There will be a big increase in multi year Ice this year!

      If it is reported at all!

    • indeed, we were often told it is volume that is important. let us see how it is spun come melt season when the compacted ice stubbornly refuses to melt for the warmists.

  9. Robert Cook, “I am open to comments and observations. Logically – You would assume greater amounts of solar energy are reflected from the increased sea ice area, less heat is absorbed over the Arctic summer months, and so there is less melting in July-August-September, and so the sea ice area in September is expected to be even higher.
    But that scenario does not occur.”
    That is because the solar insolation angle of incidence at higher latitudes is so low.
    The primary energy source warming the poles is ocean currents and atmospheric compression. Atmospheric expansion (cooling) in the tropics results in warming the poles as the air is compressed, above the poles.

    • Genghis

      That is because the solar insolation angle of incidence at higher latitudes is so low.

      You’re right, and I use each hour’s actual solar elevation angle when we calculate the direct solar energy on each ‘excess” or “missing” square meter of sea ice each month on the 22nd. Open Ocean Albedo also changes with solar elevation angle, and sea ice albedo changes with each month – getting substantially lower between May to June – to a minimum in late July, then back up as the sea ice begins its annual re-freeze in mid-August.

    • I am inclined to agree, Genghis. Ocean currents are without doubt key as the real source of “heat” in the Arctic isn’t insolation at all, it is heat transport from latitudes where insolation actually does deliver a substantial amount of heat. Even small deviations in the strength or specific trajectory of the primary branches of the Gulf Stream as it moves a river of tropical heat north to warm the Arctic and Europe can have large effects. Also, ice of any sort ends up being freshwater ice because the salt literally melts its way out of the ice and falls into the sea. This can cause a complex oscillation of salinity/density near the surface as ice forms (salting the near-surface water so that its density increases and creates instabilities and vertical turnover) and melts (locally diluting the sea surface even as it moves it through maximum thermal density).
      I hadn’t thought of atmospheric compression as a source of heating (really heat transport) per se and don’t know if this makes sense or not. I don’t have a good feel for the magnitudes involved and air pressure near the poles is often enough low as much as high IIRC, so I’m not sure what differential/average effect this would produce. One thing compression DOES do is increase the opacity of the atmosphere in the LWIR bands, both by increasing local density and by reducing the mean free time between collisions and hence increasing the absorptive linewidths. This in turn should alter the scale height where the atmosphere becomes effectively transparent in radiative transport. But most of these sorts of things seem like weather, not climate, and it is hard for me to see how they would produce a persistent memory effect (needed to explain annual timescale correlations) because of the comparatively low heat capacity of the land surface or atmosphere itself. So I think the explanation needs to be in the high heat capacity, long memory ocean, and the Arctic ocean itself may be the tail being wagged by tropical heat chaotically delivered, not the dog doing the wagging.
      rgb

  10. I just realized that the 2 standard deviation lines shown on these graphs are a bit bogus when used to examine small excursions. With less than 40 data points for any particular date there just isn’t enough data to talk about 2 SD’s.
    To create the curve width they no doubt had to ‘bin’ the data around a range of dates. Therefore when examining any excursion and using the SD’s to judge frequency you have to consider a similar ‘bin’ size.

    • Yes. And, since the actual (plotted) 1 std deviation and 2 std deviation bands on the various daily laboratory reports vary with each day-of-year, the “long-term” plot degrades quickly into overlapping mush.

  11. I am really puzzled, why are the Arctic and Antarctic out of step in the timing of maximum and minimum, why do we get a double peak in the global ice extent graph?

  12. Averaging is not an effective filter, try using a low pass filter. 13day gaussian is probably a minimum and will require about 39days after max to detect it.
    Once the fortnightly ripple ( probably lunar tides ) is filtered out we can see that melting season has shortened notably and is below 6mo since 2010.
    Amazing the way the Royal Soc. manage to identify the negative feedback to ice cover change but then still come back to the “death spiral” mantra.
    https://climategrog.wordpress.com/?attachment_id=964

  13. “All sea ice that melted one year will definitely re-freeze the next winter. “
    What? That doesn’t make sense. Where does the unfrozen ice hang out?
    And an article about variation sea ice extent and no mention of the amt of new sea ice vs multi year ice?
    Amazing.
    And for all you worrying about temps, appreciate the weird thing about sea water (or ice salted at ski areas): it freezes at 27 or 28 F but that ice doesn’t melt until 32 (because the salt is excluded from the frozen ice crystals.)

    • Hysteresis? There’s no way that isn’t a factor in something…
      (but no, it’s all about CO2)
      By the way, as I’ve been saying ever since “death spiral watch” began over a decade ago, it doesn’t matter… not even a little. Sea ice extent is a bad metric to use for anything. Low sea ice is an indication that MORE heat has been brought from the tropics, and thus more heat is leaving the system.
      Low sea ice is not something to worry about, it’s an indication that a gigantic, automatic, in-built temperature control system is working exactly as it has for billions of years. No uncontrolled warming is even remotely possible as long as there is variation between years. Trends don’t even matter.

  14. It is fairly well accepted that there is anti-correlation at 1 year lag in Arctic sea ice. Basically, it tends to bounce from one direction to the other, again this is the strong neg. feedback the RS explain. Then ignore.

  15. Care is needed in fitting “trends”. This is what warmists do all the time, the result usually depends up on your choice of start and end points and very subjective. There seems to be a roughly 5.5y repetitive pattern on top of a longer term reversal:
    http://climategrog.files.wordpress.com/2013/09/art_nh_ice_area_short_anom_2007_final.png
    https://climategrog.wordpress.com/2013/09/16/on-identifying-inter-decadal-variation-in-nh-sea-ice/
    The death spiral is dead:
    http://climategrog.wordpress.com/?attachment_id=972

  16. Pippen Tool says:
    Where does the unfrozen ice hang out?
    On Planet Earth, it’s called ‘water’, and it hangs out in the ocean.
    Where does unfrozen water hang out on your planet?

  17. Robert, your mystery concerning albedo and its effect on arctic ice at Max and Min is not much of a mystery at all. The angle of incidence of the suns rays are most important. North of 70 in summer, because of the angle of incidence 40-60% of the incident sunlight is reflected (albedo average ~50), in winter, yeah its over 90 but reflected light in summer makes incident sunlight not very warming. Ocean currents, on the other hand melt from beneath the ice and this is the strongest effect.
    http://www.eoearth.org/files/153301_153400/153374/jul_clear_albedo_87_sm.jpg

  18. “But, from 1979 to early 2000, the Arctic sea ice anomaly declined slowly, but remained within 2 std deviations the entire period. It then took a rapid drop, then oscillated widely but always around an “average” lower level of -1.0 Mkm^2 in 2005-2015.”
    That image, particularly lines you drew around it are all wrong.
    The decline did not significantly change before 2002, four years after 1998’s El Nino.
    And there’s definitely no straight line from 2007 to today. That time is rather characterized by wild changes up and down, much wilder than the 2002-2007 decline, just in both directions.
    Also the notion of “wide oscillations” is unfounded. There’s always wide oscillation of the annual cycle, that’s why we calculate anomalies to get rid of them. The change between 2007 and 2013 was a small persistent deviation from the exact form of that oscillation. Recalculating annual cycle using 2007-2013 form returns anomaly with exactly the same amount of noise as the rest of the record.
    http://i.imgur.com/SBk44tQ.png
    Why all this, I’m not sure. But I believe rather than reflecting sunlight, the polar ice serves as a thermal insulator for sea water below it. Sea water in polar region is known to have almost constant temperature all the year long. To keep that temperature, sometimes more, and sometimes less insulation may be needed.

  19. PAcookPE1978 says: “Of course, we have no satellite data for Arctic (or Antarctic) sea ice extents before 1979.”
    ————
    Your statement above just is not true. Satellite data exists from 1974 on. See Steve Goddard’s site for the graph showing it.
    “But it is worse than it seems. Arctic data is cleverly cut off at the 1979 peak, but the 1990 IPCC report showed that there was much less ice in 1974 than in 1979.”
    The above quote is from Steve’s site about the start of knowing ice extent. We need to use the 1974 data.

  20. And what effect does the breaking of ice with the huge atomic powered ice breakers have? We know strong winds break up ice and cause faster melt does the same apply to ice breakers?

  21. I speculate that the 1998 Super El Nino warmed the Arctic ocean reducing sea ice until it stabilized in 2007. I propose the physical mechanism for this Arctic warming is the strengthening of the Westerlies that transport heat from the tropics to the polar region during El Ninos.

  22. what i find striking is that the “whole anomaly” can be reduced to only 2 basins: the sea of ochotsk north of Japan and the Bering sea. for all the rest it is all really like “normal”
    i also suspect warmer sea currents causing this after all we had a few years of much below average tropical cyclone activity. They forget they follow ocean currents and they cool the oceans. Thus less cyclones means more warm tropical water that gets transported polewards….

  23. At high latitudes, does open water absorb more solar or radiate more to space in late summer? If the latter dominates, open water becomes a negative feedback to midsummer warmth (a limited effect anyway, due to incidence angles).

  24. What is interesting – and may be important, or may be totally a distraction is the “timing” of that maximum point. Look again across the plots above for Sea Ice Extents. Notice how the Arctic Sea Ice extents have been “peaking” later the past 8 to 15 years? Even the Cryosphere average for 1980 – 2010 peaks significantly earlier than it does the past 10 years. So, each day after the spring equinox that the peak sea ice delays causes more and more solar energy to be reflected (lost form the earth’s heat BALANCE back into space) that it was back in earlier “baseline” years.
    Interesting then that the maximum this year appears to have been in the middle of February, i.e. earlier than the years you refer to.

Comments are closed.