Arctic Inversions and Intrusions

Early-spring sunlight hits ice in the Chukchi Sea near Barrow, Alaska, in March 2009. UCAR

An earlier post Arctic Ice Factors discussed how ice extent varies in the Arctic primarily due to the three Ws: Water, Wind and Weather. There are other posts on the details of Water and Wind linked below at the end, but this post looks at some ordinary and repeating Weather events in the Arctic that influence ice formation. An interesting new study prompted this essay, but first some background on heat exchange observations in the Arctic.

Ice Station SHEBA near the beginning of the drift on 28 October 1997. The Canadian Coast Guard Icebreaker Des Groseilliers served as a base of operations for the field experiment. The huts housed scientific equipment and logistical supplies.

One project in particular has provided comprehensive empirical data on the energy interface between Arctic Sea Ice and the atmosphere.  The SHEBA project collected heat exchange data on site in the Arctic as described in this article SHEBA: The Surface Heat Budget of the Arctic Ocean by Donald K. Perovich and John Weatherly, U.S. Army Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire; and Richard C. Moritz, Polar Science Center, University of Washington, Seattle.

Overview

The combination of the importance of the Arctic sea ice cover to climate and the uncertainties of how to treat the sea ice cover led directly to SHEBA: the Surface Heat Budget of the Arctic Ocean. SHEBA is a large, interdisciplinary project that was developed through several workshops and reports. SHEBA was governed by two broad goals: understand the ice–albedo and cloud–radiation feedback mechanisms and use that understanding to improve the treatment of the Arctic in large-scale climate models. The SHEBA project was sponsored _jointly by the National Science Foundation’s Office of Polar Programs Arctic System Science program and the Office of Naval Research’s High Latitude Dynamics program.

Ice Station SHEBA

On 2 October 1997, the Canadian Coast Guard icebreaker Des Groseilliers stopped in the middle of an ice floe in the Arctic Ocean, beginning the year-long drift of Ice Station SHEBA. For the next 12 months, until 11 October 1998, Ice Station SHEBA drifted with the pack ice from 75°N, 142°W to 80°N, 162°W. At any given time, there were 20–50 researchers at Ice Station SHEBA. During the year over 200 researchers participated in the field campaign, spending anywhere from just a few days to the entire year. Conducting a year-long sea ice experiment provided daunting scientific and logistic challenges: low temperatures, high winds, ice breakup, demanding instruments, and polar bears.

There was an intense measurement program designed to obtain a complete, integrated time series of every possible variable defining the state of the “SHEBA column” over an entire annual cycle. This column is an imaginary cylinder stretching from the top of the atmosphere through the ice into the upper ocean. Observations included longwave and shortwave radiative fluxes; the turbulent fluxes of latent and sensible heat; cloud height, thickness, phase, and properties; energy exchange in the boundary layers of the atmosphere and ocean; snow depth and ice thickness; and upper ocean salinity, temperature, and currents. This year-long, integrated data set provides a test bed for exploring the feedback mechanisms and for model development.

The full set of observations is available in a report entitled Reconciling different observational data sets from Surface Heat Budget of the Arctic Ocean (SHEBA) for model validation purposes

All the detailed measurements are in the report, and the takeaway findings are summarized in Figure 8 below.

Figure 8. (a) Main components of the Surface Heat Budget of the Arctic Ocean (SHEBA) surface energy budget at the Pittsburgh site. (b) Sensible and latent heat fluxes (calculated using bulk formulations). The dashed line indicates the beginning of the summer (1 April), and the dotted line marks the onset of surface melt (29 May). Fluxes are smoothed using a 7 day running mean.

Figure 8a shows how the conductive heat flux in winter (October –March) is controlled by the net longwave radiation. The net longwave radiation has large variability. It is generally high for clear sky conditions, and low for cloudy sky, and constitutes a heat loss from the surface throughout the whole year. The net shortwave radiation (Figure 8a) is steadily growing in spring and early summer with a sudden increase in mid-June when the snow cover starts disappearing and the albedo drops to a lower value. When the surface temperature is at the melting point, the energy surplus is used for melting. This heat flux becomes the major counterbalance of the net solar flux during summer (April –September).

The sensible heat flux (Figure 8b) is usually small except in winter during clear sky conditions when the air temperature is relatively higher than the surface and the wind speed is higher [see Walsh and Chapman, 1998] (see Figure 1). In general, the surface is colder than the overlying air and the sensible heat is downward. During the winter,the sensible heat flux and the net longwave radiation are generally anticorrelated (Figures 8a – 8b). That is, the heat loss from the surface to the atmosphere during clear sky conditions leads to a positive temperature gradient in the air and results in a downward sensible heat flux. The coupling between these two fluxes is discussed in more detail by Makshtas et al. [1999]. The latent heat flux (Figure 8b) is close to zero except after the onset of the melt season when it has several peaks indicating moisture transport from the surface to the atmosphere. Figure 8a shows most components of the surface energy budget together, and the residual from all fluxes.

The Effects of Polar Weather Intrusions

With this background understanding of the winter heat flux over Arctic ice, let us consider the implications of the recent study.

An interesting paper analyzes intrusive weather and estimates the connection between such events and ice extents in the Arctic. The paper is:  The role of moist intrusions in winter Arctic warming and sea ice decline in Journal of Climate 29(12):160314091706008 · March 2016 by Cian Woods and Rodrigo Caballero, Department of Meteorology, and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden

FIG. 1. Region with ONDJ SIC > 90% and trend < 2% decade-1 (gray shading). Numbered black dots show the location of the radiosonde stations: 1) Barrow, 2) Resolute, 3) Eureka, 4) Alert, 5) Ny-Ålesund, 6) Bjørnøya (Bear Island), 7) Polargmo (Heiss Island), and 8) Dikson Island. Solid black lines show the Barents Sea box (75°–80°N, 20°–80°E). Dotted lines indicate the 70° and 80°N latitude lines.

Abstract:

This paper examines the trajectories followed by intense intrusions of moist air into the Arctic polar region during autumn and winter and their impact on local temperature and sea ice concentration. It is found that the vertical structure of the warming associated with moist intrusions is bottom amplified, corresponding to a transition of local conditions from a ‘‘cold clear’’ state with a strong inversion to a ‘‘warm opaque’’ state with a weaker inversion. In the marginal sea ice zone of the Barents Sea, the passage of an intrusion also causes a retreat of the ice margin, which persists for many days after the intrusion has passed. The authors find that there is a positive trend in the number of intrusion events crossing 708N during December and January that can explain roughly 45% of the surface air temperature and 30% of the sea ice concentration trends observed in the Barents Sea during the past two decades.

An injection event is defined as a vertically integrated northward moisture flux across 708N in excess of 200 Tg day21 deg21 that is sustained for at least 1.5 days and occupies a contiguous zonal extent of at least 98 at all times.

The case study in Fig. 2 shows that the passage of an intrusion can induce local warming of over 20 K in the central Arctic. Here, we examine the typical thermodynamic impact of intrusions, focusing on the fully ice-covered interior of the Arctic basin—specifically, the region where monthly climatological SIC exceeds 90% and shows negligible trend across the data record. This region is shaded gray in Fig. 1.

FIG. 2. Case study of an intrusion event beginning over northern Norway at 1800 UTC on 27 December 1999. Each panel shows a snapshot at a time relative to the beginning of the event as indicated in the lower-right corner. Gray lines show centroid trajectories with gray dots at 1-day intervals. Shading shows surface air temperature anomaly from a 6-hourly, smoothed seasonal cycle, arrows show 10-m wind, and the heavy black line shows the 15% SIC contour. As a reference, the dashed black line shows the 15% SIC contour 5 days before the beginning of the event. Dotted line is the 70°N latitude line. Thin black lines in the +5 days panel show the Barents Sea box.

An example intrusion event is shown in Fig. 2. The injection occurs over the northern tip of Norway and lasts for 1.75 days, yielding seven centroid trajectories. As the injection event progresses, its centroid shifts slowly eastward, giving some zonal spread in centroid trajectories. The flow field during the event features a large-scale dipole straddling the North Pole, with cyclonic circulation over the Atlantic/North American sector and an anticyclone over Eurasia. The trajectories reflect this structure, heading toward the North Pole after injection and then curving cyclonically to exit the Arctic over North America. The intrusion event is associated with large surface air temperature anomalies in the central Arctic and a retreat of the sea ice margin in the Barents Sea, topics we discuss in detail in sections 4 and 5 below.

To focus on intrusions that reach deep into the Arctic basin, events in which fewer than 40% of the trajectory ensemble members reaches 808N over 5 days are discarded. This leaves us with a final dataset of 359 intrusion events from 1990 to 2012, or ;16 per ONDJ season.

It is clear from Fig. 3 that by far the largest fraction of intrusions enters the Arctic through the Atlantic sector, with smaller numbers entering over the Labrador Sea and Greenland and from the Pacific. Interestingly, intrusions entering via the Atlantic and the Barents/Kara sector typically turn cyclonically toward North America—just as in the case study above—while those entering to the east of the Kara Sea typically turn anticyclonically and exit over Siberia. This suggests that moist intrusions into the Arctic are typically associated with cyclonic anomalies over eastern North America and anticyclonic anomalies over western Siberia, consistent with previous work.

Summary

FIG. 5. (top) Humidity and (bottom) temperature profiles (left) in the ice-covered Arctic Ocean during ONDJ and (right) in the Barents Sea box during DJ. Solid lines show climatologies over the respective regions and seasons (representative of typical conditions in the absence of an intrusion event), and dashed lines show profiles at the time of maximum surface warming during a composite intrusion event (representative of conditions at the peak of the event).

A key feature of the warming trend in the Arctic is that it is bottom amplified (i.e., that it is in fact a trend toward a weakening of the climatological temperature inversion that prevails in ice-covered regions of the Arctic basin in winter). This feature has previously been mostly attributed to increased upward turbulent heat flux due to sea ice loss (Serreze et al. 2009; Screen and Simmonds 2010a,b).

Our results suggest a more nuanced view. The passage of an intrusion affects local conditions by inducing a transition from a “cold clear” state with a strong inversion to a “warm opaque” state with a much weaker inversion, in agreement with recent modeling work (Pithan et al. 2014; Cronin and Tziperman 2015). This yields an overall bottom-amplified local temperature perturbation, owing largely to surface heating by increased downwelling longwave radiation.

An increase in the frequency of intrusions can therefore drive bottom-amplified warming trend even in the absence of sea ice loss. In addition, the intrusions themselves drive sea ice retreat in the marginal zone and thus promote the upward turbulent fluxes that help produce bottom-amplified warming.

Our results agree with other recent work showing a strong impact of poleward moisture flux on Arctic sea ice variability and trends (D.-S. R. Park et al. 2015; H.-S. Park et al. 2015a,b). Since most of the moisture flux into the Arctic occurs in a small number of extreme events (Woods et al. 2013; Liu and Barnes 2015), it is natural to take an event-based approach as we do here, which allows us to study the structure of the intrusion events and their link to dynamical processes in the Arctic region and at lower latitudes.

Predicted surface air temperature trends (Fig. 9f) are greatest in the Barents Sea area extending into the central Arctic in agreement with observations (Fig. 9k), with the average trend predicted in the Barents Sea box approximately 45% of that observed. This localization of the trends arises both because intrusion counts have risen most rapidly in that region (Fig. 8b) and because individual intrusions have the greatest impact in that region (Fig. 9a). The predicted trend has a peak amplitude of about 3 K decade-1, about half of the observed value. For SIC the predicted trend (Fig. 9g) again coincides spatially with the observed trend (Fig. 9l) and peaks at about 10% decade, or about 1/3 the observed value at the same location, with the average predicted trend in the Barents Sea box being approximately 30% of that observed.

PS:

Current wind patterns over Barents and the Atlantic gateway to the Arctic can viewed at nullschool:
https://earth.nullschool.net/#current/wind/surface/level/orthographic=-6.21,74.48,522/loc=33.553,72.930

Footnote:

Arctic Sea Ice: Self-Oscillating System

Arctic Shifts between Cyclonic and Anticyclonic Wind Regimes The Great Arctic Ice Exchange

Arctic Ice Usual Suspects

Drift ice in Okhotsk Sea at sunrise.

Previous posts have noted that in March, all the Arctic seas are locked in ice, the exceptions being Bering and Okhotsk in the Pacific, and Barents and Baffin Bay in the Atlantic. And the seesaw continues, shown in the images below.  Firstly on the Atlantic side, featuring Baffin Bay and Kara, Barents, Greenland Seas.

And on the Pacific side, the only action is in Bering and Okhotsk Seas.

The overall NH extents are down from the 11-year average, and it is mostly due to deficits in the usual places: Barents, Bering and Okhotsk, somewhat offset by a surplus in Baffin. All of them melt out in September, and Bering and Okhotsk basins are effectively outside of the Arctic ocean per se.

As reported previously, 2017 peaked early, rising close to the average on day 53 in February, then losing extent and never achieving the 15M km2 threshold.  14.8 M km2 proved to be the 2017 peak daily ice extent.  2016 also lost extent throughout March, though higher than the current year, and will likely end with a higher monthly average.  2006 and 2017 are virtually tied at this point, though 2017 will likely end up higher on the month.  SII shows about 300km2 less extent for the month, but drawing closer lately.

The Table below presents the ice extents reported by MASIE for day 80 in the years 2017, 2006 and the 11-year average (2006 through 2016).

Region 2017080 Day 080
Average
2017-Ave. 2006080 2017-2006
 (0) Northern_Hemisphere 14306702 14928081 -621379 14340618 -33916
 (1) Beaufort_Sea 1070445 1069983 462 1068295 2150
 (2) Chukchi_Sea 966006 965416 590 962459 3547
 (3) East_Siberian_Sea 1087137 1086906 231 1084627 2510
 (4) Laptev_Sea 897845 897785 60 897773 71
 (5) Kara_Sea 845743 923038 -77295 933929 -88185
 (6) Barents_Sea 512177 624900 -112723 707363 -195187
 (7) Greenland_Sea 666783 636333 30449 635643 31139
 (8) Baffin_Bay_Gulf_of_St._Lawrence 1567538 1514854 52684 1099497 468041
 (9) Canadian_Archipelago 853214 852858 356 852715 499
 (10) Hudson_Bay 1260903 1258471 2432 1238627 22276
 (11) Central_Arctic 3246109 3229176 16933 3246726 -617
 (12) Bering_Sea 629171 819540 -190369 603351 25820
 (13) Baltic_Sea 43534 89187 -45653 153837 -110304
 (14) Sea_of_Okhotsk 647215 940291 -293076 819326 -172111
 (15) Yellow_Sea 0 158 -158 1067 -1067
 (16) Cook_Inlet 9489 7555 1934 7101 2388

The 2017 deficit to average is largely due to Okhotsk and Bering declining early, along with Barents and Kara.  A surplus in Baffin somewhat offsets these, especially in comparison with 2006.

To summarize, central Arctic seas are locked in ice, while extents have started to decline in the peripheral basins.  As of day 80, extents in 2017 are 4% below average and tied with 2006.

 

 

 

 

 

Honey, I Shrunk the Arctic Ice! Not.

Image is from Honey, I Shrunk the Kids, a 1989 American science fiction family film produced by Walt Disney Pictures.

The notion that man-made global warming causes Arctic ice to melt took a major hit with a recent publication.  The article is Influence of high-latitude atmospheric circulation changes on summertime Arctic sea ice by Qinghua Ding, Axel Schweiger, Michelle L’Heureux, David S. Battisti, Stephen Po-Chedley, Nathaniel C. Johnson, Eduardo Blanchard-Wrigglesworth, Kirstin Harnos, Qin Zhang, Ryan Eastman & Eric J. Steig.  (Warning: Reliability of published papers diminishes as numbers of co-authors increases.)

The paper was published online by Nature Climate Change on 13 March 2017. It is behind a paywall, but the reactions to it are revealing.  The abstract says:

The Arctic has seen rapid sea-ice decline in the past three decades, whilst warming at about twice the global average rate. Yet the relationship between Arctic warming and sea-ice loss is not well understood. Here, we present evidence that trends in summertime atmospheric circulation may have contributed as much as 60% to the September sea-ice extent decline since 1979. A tendency towards a stronger anticyclonic circulation over Greenland and the Arctic Ocean with a barotropic structure in the troposphere increased the downwelling longwave radiation above the ice by warming and moistening the lower troposphere. Model experiments, with reanalysis data constraining atmospheric circulation, replicate the observed thermodynamic response and indicate that the near-surface changes are dominated by circulation changes rather than feedbacks from the changing sea-ice cover. Internal variability dominates the Arctic summer circulation trend and may be responsible for about 30–50% of the overall decline in September sea ice since 1979. (my bolds)

Announcements of the finding were welcomed by skeptics and lukewarmists as an indication that climatologists were taking off their CO2 blinders and at last admitting to natural forces internal to the climate system.  Some responses were:

Arctic Ice Loss Driven by Natural Swings

Arctic ice loss driven by natural swings, not just mankind

Study in journal Nature: HALF of Arctic ice loss driven by natural swings — not ‘global warming’

Arctic Ice Alarmists are finding themselves skating on thin ice, as evidenced by their articles attempting to control the damage.  Some of these titles are:

We Deserve Half the Blame for Declining Arctic Sea Ice (Discover)

Humans to blame for bulk of Arctic sea ice loss: study (Phys.org)

Human activity is driving retreat of Arctic sea ice (from the misnamed Skeptical Science blog)

Why Alarmists are Twisting in the Wind

The full paper is behind a paywall, but we have description of the method and content by the lead author in an article at Popular Science Up to half of the Arctic’s melt might be totally natural–But climate change is still responsible for the rest.  He begins with his profession of faith:

“Anthropogenic forcing is still dominant — it’s still the key player,” said first author Qinghua Ding, a climate scientist at the University of California Santa Barbara. . .”But we found that natural variability has helped to accelerate this melting, especially over the past 20 years.”  A colleague adds:  “The results of Ding et al. do not call into question whether human-induced warming has led to Arctic sea-ice decline – a wide range of evidence shows that it has”.

This is the shibboleth demanded from any and all scientists who do not wish to be called “deniers” and cast into the outer darkness.

Note: A shibboleth is an old belief or saying that is repetitively cited but untrue.  This meaning evolved from its earlier significance as a word or custom whose variations in pronunciation or style are used to distinguish members of ingroups from those of outgroups, with an implicit value judgment based on familiarity with the shibboleth.(Wikipedia)


“The tribe has spoken.  Time for you to go!”

What Ding et al. Studied

Ding goes on to describe the nature of their analysis. (From Popular Science)

“There is a mismatch between the model’s output and the observation,” said lead author Qinghua Ding, a professor in the Geography Department at the University of California Santa Barbara. “Observation shows very fast, very abrupt sea ice melting, whereas the climate model cannot capture the fast melting.”

To understand why, Ding and his team focused on the connection between September sea-ice extent (or how much of the Arctic sea had at least 15 percent sea ice) and the preceding summer’s (June-August) atmospheric circulation. Ding knew from earlier work that tropical circulation can affect seasonal variability of sea ice in the Arctic.

“In the model we turned off all CO2 forcing,” said Ding, or all climate changes that were “forced” by the addition of carbon dioxide into the atmosphere. “And we still got some sea ice melting, that was very similar to the observation.”

“If the circulation changes are caused by anthropogenic greenhouse warming (or other human or natural external forcings such as ozone depletion, aerosol emissions, or solar activity) this pattern of atmospheric change should emerge as a clear signature when averaging together many climate model simulations of this period,” Neil Swart, a Research Scientist with Environment and Climate Change Canada who wasn’t involved in the new study, wrote in an accompanying article.

But when Ding averaged the climate models together, the air circulation changes cancelled each other out—like a balanced equation. They only data that remained in the models was responding to external forcings, like greenhouse gas emissions. In other words, Ding found that between 30-50 percent of the arctic melting is due to these unforced, or non-climate change caused variations—and that with this factored in, the climate models were generally accurate. The increased rapidity of Arctic melting was due to natural variations outside of the scope of the climate change models.

What Can Be Learned from Ding et al.

First note that they are climate modelers studying the behavior of models when parameters are manipulated.  It is encouraging that they notice the incompleteness of their models leads to discrepancies from reality.  This is a step in the right direction.

Second, note that the CO2 forcing is actually their term for all external forcings, including solar, aerosols etc.  They seem to be blind to oceanic multi-decadal and multi-centennial oscillations.  They make a leap of faith when they attribute every factor outside of atmospheric circulation to CO2.

Others more comprehensive in their research have concluded that fluctuations in the ocean water structure drive both ice extent changes and atmospheric circulations. See Arctic Sea Ice: Self-Oscillating System featuring the work of V. F. Zakharov and others at the Arctic and Antarctic Research Institute in St. Petersburg.

Summary

Some climate modelers are undermining core beliefs even while using a flawed methodology based on studying models rather than nature itself. Alarmists are forced into scrambling to continue blaming humans for declining Arctic Sea Ice. When the effects of oceanic circulations are added to atmospheric effects, there is little influence left for CO2.

Spinning the papers to keep the narrative alive.

Footnote:

The abstract mentions downwelling longwave radiation, a theoretical effect that in practice is overwhelmed by massive heat transfers upward into space.

In the Arctic (and also at the South Pole), the air is in direct contact with an infinite heat sink: outer space. The tropopause (where radiative loss upward is optimized) is only 7 km above the surface at the poles in winter, compared to 20 km at the equator. There is no door to open or close; the air is constantly convecting any and all energy away from the surface for radiation into space.

Instead of an open door, Arctic ice melts when the sun climbs over the horizon. Both the water and air are warmed, and the ice cover retreats until sundown in Autumn.

Most people fail to appreciate the huge heat losses at the Arctic pole. Mark Brandon has an excellent post on this at his wonderful blog, Mallemaroking.

By his calculations the sensible heat loss in Arctic winter ranges 200-400 Wm2.

The annual cycle of sensible heat flux from the ocean to the atmosphere for 4 different wind speeds

As the diagram clearly shows, except for a short time in high summer, the energy flow is from the water heating the air.

“Then the heat loss over the 2×109 m2 of open water in that image is a massive 600 GW – yes that is Giga Watts – 600 x 10^9 Watts.

If you want to be really inappropriate then in 2 hours, that part of the ocean lost more energy than it takes to run the London Underground for one year.

Remember that is just one component and not the full heat budget – which is partially why it is inappropriate. For the full budget we have to include latent heat flux, long wave radiation, short wave radiation, energy changes through state changes when ice grows and decays, and so on. Also large heat fluxes lead to rapid sea ice growth which then insulates the ocean from further heat loss.”

 

 

 

 

Arctic Ice High Jump

For ice extent in the Arctic, the bar is set at 15M km2. The average in the last 11 years occurs on day 73 at 15.07M before descending. Most years are able to clear 15M, except for 2006, 2007 and 2015 who topped out below that height.

Yesterday, March 2, 2016 cleared 15M, but will not reach that level again. 2016 will now drop down to 14.6M, rise to day 84 average of 14.9M, then start the descent into spring and summer. Typically, Arctic ice extent loses 67 to 70% of the March maximum by mid September, before recovering the ice in building toward the next March.

arctic-ice-2017061

As reported previously, 2017 rose to the average in February, then lost extent for two days and is now increasing again.  The next two weeks will be interesting. The average year in the last eleven gained about 20k km2 from now to mid March. But the variability ranged from 2015 losing 350K while 2010 gained 300k km2. What will the ice do this year?  Where will 2017 rank in the annual Arctic Ice High Jump competition?

Drift ice in Okhotsk Sea at sunrise.

As reported previously, Arctic ice extents are solid in most seas, but continue to fluctuate at the margins. In the latter part of February 2017 there was a great leap upward for nine days, nearly reaching average and surpassing 2016, before falling back after day 53. The surplus over 2006 is now 500k km2. SII reports about 360k km2 less extent than MASIE.

arctic-ice-2017058

The Atlantic upward leap and back in Barents and Baffin.

output_fxzrvq

Note both Barents and Baffin pulled back slightly.

The Pacific shifting up and down in Bering and Okhotsk.

output_xhr2x3Note that Okhotsk continued to gain while Bering pulled back since day 53.

While the seesaws are tilting back and forth on the margins, the bulk of the Arctic is frozen solid. And with limited places where more extent can be added, the pace of overall growth has slowed.

The table below shows ice extents in the seas comprising the Arctic, comparing 2017 day 058 with the same day average over the last 11 years and with 2006.

Region 2017058 Day 058
Average
2017-Ave. 2006058 2017-2006
 (0) Northern_Hemisphere 14652502 14960594 -308093 14148072 504430
 (1) Beaufort_Sea 1070445 1070111 334 1069711 734
 (2) Chukchi_Sea 966006 965342 664 961796 4210
 (3) East_Siberian_Sea 1087137 1087095 43 1086702 435
 (4) Laptev_Sea 897845 897835 10 897773 71
 (5) Kara_Sea 933720 927244 6476 899871 33849
 (6) Barents_Sea 550872 612576 -61704 466622 84251
 (7) Greenland_Sea 595616 638641 -43025 575532 20084
 (8) Baffin_Bay_Gulf_of_St._Lawrence 1496540 1472634 23906 1290424 206116
 (9) Canadian_Archipelago 853214 852984 230 852715 499
 (10) Hudson_Bay 1260903 1260333 571 1257077 3827
 (11) Central_Arctic 3218090 3221265 -3176 3181409 36681
 (12) Bering_Sea 547532 742754 -195222 549141 -1609
 (13) Baltic_Sea 70844 117633 -46789 111391 -40547
 (14) Sea_of_Okhotsk 1048295 1043395 4900 877854 170441
 (15) Yellow_Sea 1420 13921 -12501 8431 -7011
 (16) Cook_Inlet 9940 9665 275 4686 5254

The table shows that 2017 ice extent exceeds 2006 by about 500k km2 at this date. Surpluses are sizeable in Barents, Baffin and Okhotsk, with only the Baltic showing a deficit.  Baffin and Okhotsk are now average, and the 300k km2 deficit to average comes from Bering in the Pacific, and Barents and Greenland Seas on the Atlantic side

The big picture compares this day in 2017 with 2006.  Not much change overall, but a slight increase of 500k km2.

output_4fhczm

 

Arctic Ice Cresting at Feb. End

Drift ice in Okhotsk Sea at sunrise.

As reported previously, Arctic ice extents are solid in most seas, but continue to fluctuate at the margins. In the latter part of February 2017 there was a great leap upward for nine days, nearly reaching average and surpassing 2016, before falling back after day 53. The surplus over 2006 is now 500k km2. SII reports about 360k km2 less extent than MASIE.

arctic-ice-2017058

The Atlantic upward leap and back in Barents and Baffin.

output_fxzrvq

Note both Barents and Baffin pulled back slightly.

The Pacific shifting up and down in Bering and Okhotsk.

output_xhr2x3Note that Okhotsk continued to gain while Bering pulled back since day 53.

While the seesaws are tilting back and forth on the margins, the bulk of the Arctic is frozen solid. And with limited places where more extent can be added, the pace of overall growth has slowed.

The table below shows ice extents in the seas comprising the Arctic, comparing 2017 day 058 with the same day average over the last 11 years and with 2006.

Region 2017058 Day 058
Average
2017-Ave. 2006058 2017-2006
 (0) Northern_Hemisphere 14652502 14960594 -308093 14148072 504430
 (1) Beaufort_Sea 1070445 1070111 334 1069711 734
 (2) Chukchi_Sea 966006 965342 664 961796 4210
 (3) East_Siberian_Sea 1087137 1087095 43 1086702 435
 (4) Laptev_Sea 897845 897835 10 897773 71
 (5) Kara_Sea 933720 927244 6476 899871 33849
 (6) Barents_Sea 550872 612576 -61704 466622 84251
 (7) Greenland_Sea 595616 638641 -43025 575532 20084
 (8) Baffin_Bay_Gulf_of_St._Lawrence 1496540 1472634 23906 1290424 206116
 (9) Canadian_Archipelago 853214 852984 230 852715 499
 (10) Hudson_Bay 1260903 1260333 571 1257077 3827
 (11) Central_Arctic 3218090 3221265 -3176 3181409 36681
 (12) Bering_Sea 547532 742754 -195222 549141 -1609
 (13) Baltic_Sea 70844 117633 -46789 111391 -40547
 (14) Sea_of_Okhotsk 1048295 1043395 4900 877854 170441
 (15) Yellow_Sea 1420 13921 -12501 8431 -7011
 (16) Cook_Inlet 9940 9665 275 4686 5254

The table shows that 2017 ice extent exceeds 2006 by about 500k km2 at this date. Surpluses are sizeable in Barents, Baffin and Okhotsk, with only the Baltic showing a deficit.  Baffin and Okhotsk are now average, and the 300k km2 deficit to average comes from Bering in the Pacific, and Barents and Greenland Seas on the Atlantic side

The next two weeks will be interesting. The average year in the last eleven gained about 100k km2 from now to mid March. But the variability ranged from 2015 losing 300K while other years gained 400k km2. What will the ice do this year?

The big picture compares this day in 2017 with 2006.  Not much change overall, but a slight increase of 500k km2.

output_4fhczm

Arctic Ice Great Leap Upward

arctic-ice-2017050

Recent posts on Arctic ice talked about an ice dance and seesaws in both Atlantic and Pacific basins.  But the fluctuations are over, and ice is forming fast.

In just six days Arctic ice extent grew 455k km2, now tied with 2016.  Ice extent in 2006 has fallen 490k behind at this date, and will go lower by month end.  Sea Ice Index from NASA@NSIDC also shows ice increasing, but still lags behind by ~400k km2.

Here are images of the great leap upward in the last week, from day 44 to day 50 (Feb. 19, 2017)

Ice growing in the Atlantic seas:

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Ice growing in the Pacific seas, and showing 2006 day 050 as a reference.

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The table below shows this year compared to the 11-year average and to 2006.

Region 2017050 Day 050
Average
2017-Ave. 2006050 2017-2006
 (0) Northern_Hemisphere 14743198 14851871 -108673 14251849 491349
 (1) Beaufort_Sea 1070445 1070111 334 1069711 734
 (2) Chukchi_Sea 966006 964552 1454 954122 11884
 (3) East_Siberian_Sea 1087137 1087038 99 1086081 1056
 (4) Laptev_Sea 897845 897835 10 897773 71
 (5) Kara_Sea 928805 918103 10702 902175 26631
 (6) Barents_Sea 508018 600373 -92355 488506 19512
 (7) Greenland_Sea 606503 635799 -29296 572979 33525
 (8) Baffin_Bay_Gulf_of_St._Lawrence 1517595 1446871 70725 1286797 230799
 (9) Canadian_Archipelago 853214 852984 230 852715 499
 (10) Hudson_Bay 1260903 1260391 512 1257433 3470
 (11) Central_Arctic 3238980 3214106 24874 3207097 31882
 (12) Bering_Sea 717887 771682 -53796 649938 67949
 (13) Baltic_Sea 52798 114323 -61525 93848 -41050
 (14) Sea_of_Okhotsk 957006 954616 2390 852621 104386
 (15) Yellow_Sea 15475 22222 -6747 13586 1889
 (16) Cook_Inlet 9671 11778 -2107 9530 141

The only deficit to 2006 is in the Baltic, while major surpluses are in Baffin, Bering and Okhotsk.  2017 is slightly below average in Barents, Bering and the Baltic, partly offset by being above average in Baffin and Central Arctic.

 

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Arctic Ice Seesaw

Mid February is about a month away from the annual maximum Arctic ice extent, and measurements continue to seesaw in the two dynamic places where freezing and drifting cause gains and losses in sea ice. In each region, the gains and losses teeter-totter between two basins.

Here is the Atlantic seesaw with Barents and Baffin.

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And here is the Pacific seesaw with Bering and Okhotsk.

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While the seesaws are tilting back and forth on the margins, the bulk of the Arctic is frozen solid. And with limited places where more extent can be added, the pace of overall growth has slowed.

arctic-ice-2017044
The graph shows that 2017 and 2006 are virtually tied at this date. It shows both years are below average by about 450k km2, and SII adds a further deficit by showing 2017 averaging in February ~400k km2 lower than MASIE.

The table below shows ice extents in the seas comprising the Arctic, comparing day 044 2017 with the same day average over the last 11 years and with 2006.

Region 2017044 Day 044
Average
2017-Ave. 2006044 2017-2006
 (0) Northern_Hemisphere 14287848 14759423 -471575 14318694 -30846
 (1) Beaufort_Sea 1070445 1070111 334 1069711 734
 (2) Chukchi_Sea 966006 965614 392 966006 0
 (3) East_Siberian_Sea 1087137 1087131 6 1087103 35
 (4) Laptev_Sea 897845 897835 10 897773 71
 (5) Kara_Sea 908380 908367 12 932924 -24545
 (6) Barents_Sea 363927 581052 -217125 507771 -143844
 (7) Greenland_Sea 565090 633257 -68167 592221 -27131
 (8) Baffin_Bay_Gulf_of_St._Lawrence 1564353 1451561 112792 1209203 355150
 (9) Canadian_Archipelago 853214 852984 230 852715 499
 (10) Hudson_Bay 1260903 1260476 427 1257433 3470
 (11) Central_Arctic 3209792 3215238 -5446 3178718 31074
 (12) Bering_Sea 564241 759583 -195342 889465 -325224
 (13) Baltic_Sea 59994 105815 -45822 68543 -8549
 (14) Sea_of_Okhotsk 834828 895634 -60806 720201 114628
 (15) Yellow_Sea 17654 31061 -13407 20909 -3255
 (16) Cook_Inlet 9131 12083 -2952 9530 -399

The table indicates some differences in locations of ice surpluses and deficits. Bering Sea has been the largest deficit this year, while Barents is now matching it by losing ~100k in the last week. Greenland Sea is also down slightly compared to average and to 2006. Baffin Bay is the largest surplus to average and to 2006. Okhotsk lost more than 200k km2 in recent days, but still exceeds 2006 by 115k.

The second half of February will be interesting. The average year in the last eleven gained about 200k km2 from now to month end. But the variability ranged from 2006 losing 170K to 2012 gaining 590k km2. What will the ice do this year?

The polar bears have a Valentine Day’s wish for Arctic Ice.

welovearcticicefinal

And Arctic Ice loves them back, returning every year so the bears can roam and hunt for seals.

Footnote:

Seesaw accurately describes Arctic ice in another sense:  The ice we see now is not the same ice we saw previously.  It is better to think of the Arctic as an ice blender than as an ice cap, explained in the post The Great Arctic Ice Exchange.

Arctic Ice Going and Coming

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As I said previously, most of the Arctic seas are now frozen solid, so all the action is confined to just two places where ice will grow or not, making the difference between this year and others.  There is a lot of fussing from alarmists about a storm bringing warm air from the North Atlantic, and this is indeed affecting the ice extent in Barents Sea, one of the two dynamic places at this point in the year.

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-18.40,68.10,459/loc=2.182,47.571

The wind pattern is visible in the nullschool image link above.  And we can see some ice retreating in Barents at this time.  However, Nature has a way of giving back when she takes away, and in this case, Baffin is growing more than Barents is losing.

In these two weeks, Barents first grew 144k km2 of ice up to 492k km2 extent, besieging Svalbard, then lost 53k km2.  At the same time, Baffin grew steadily to gain 240k km2 in 10 days to arrive at 1523k km2, more than 100k above average.

Similarly, both freezing and melting appear in the other dynamic place, the Pacific seas of Okhotsk and Bering.

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-195.48,46.95,606/loc=143.378,43.684

There a pair of subpolar gyres are diverting southern air away from Bering and Okhotsk, allowing normal freezing to return.

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In the Pacific, Okhotsk grew 154k km2 of ice to reach 1.2 M km2, 25% above the 11-year average, and then gave back 94k.  Meanwhile in the last 16 days, Bering first gained 69k km2, then lost 163k km2, then gained back 90k in the last 5 days, almost the same extent as the beginning.

Summary

The end result of the fluctuations is an overall  gain of 450k km2 in Arctic ice extent despite the influence of weather events.  The only place where Arctic ice extent is down this year is in Bering Sea, more than offset by Baffin and Okhotsk.

Footnote:
The nullschool image shows that Kamchatka Peninsula protects Okhotsk from prevailing wind, and may explain why ice formation is not inhibited there as it is in Bering.

 

 

 

Ice Dance in the Pacific

With the Arctic ice extent maximum due in March, there are only two places where ice will grow or not, making the difference between this year and others.  Yesterday, we looked at one of them Ice Taking Hold in Barents Sea and saw dramatic growth in a single week.

This post features the Pacific seas of Okhotsk and Bering, where a peculiar dance can be seen.  The images come from MASIE showing the difference between Feb. 1 and Feb. 4, yesterday.

pac-ice-day35

In those three days Okhotsk grew 103k km2 of ice, while Bering lost 33k km2.  Bering has the same extent now as on Jan. 19, having gained and then lost 140k km2 over those two weeks.  Okhotsk is now at 1.2 M km2, 25% above the 11-year average.

The only place where Arctic ice extent is down this year is in Bering Sea.

Update February 6

Pethefin provides in his comment an informative link to the current wind patterns over these seas:
https://earth.nullschool.net/#current/wind/surface/level/orthographic=-195.48,46.95,606/loc=143.378,43.684

As the nullschool graphic shows, the polar gyres are pulling southern air up and over Bering Sea.  The Kamchatka Peninsula protects Okhotsk from that pattern, and may explain why ice formation is not inhibited as it is in Bering.

Meanwhile, on the Atlantic side, nullschool shows why Barents has been gaining ice.  The gyre is positioned southwest of Iceland and drawing most of the southern air away from Barents.

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-18.40,68.10,459/loc=2.182,47.571

 

 

Ice Taking Hold in Barents Sea

In just the last week, the progression of ice extents in Barents Sea is impressive.  The first image from MASIE is January 27, 2017.  h/t Pethefin

google-ice-day-27

Then a week later on February 3 we see that Svalbard is almost enclosed.

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In that one week Arctic ice gained 240k km2 up to 14.3 M km2, including Barents Sea adding 145k km2.  Thanks to MASIE we can see Arctic ice growing before our eyes.

One Week in Barents Sea shows Svalbard under siege.

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