My previous Arctic ice report was limited by technical difficulties, now resolved as shown by the animation above.  So this update comes a week into May, with the animation covering the last three weeks from mid April.   The dramatic melting in the Pacific basins of Bering and Okhotsk (left) sets them apart from the rest of Arctic sea ice. As noted before, those two basins are outside the Arctic circle, have no polar bears and are the first places to become open water in the Spring. Elsewhere sea ice persisted, actually growing in Barents and Greenland seas.

[The staff at National Ice Center were extremely helpful, as usual.  Their work is distinctive, valuable and deserving of your appreciation.  See Support MASIE Arctic Ice Dataset]

The melting effect on NH total ice extents during this period is presented in the graph below.

The graph above shows ice extent mid-April through May 7 comparing 2022 MASIE reports with the 16-year average, other recent years and with SII.  2022 ice extents have tracked the average, going surplus for the last 10 days. .Both 2021 and 2007 are well below average, on day 127 lower than 2022 by 318k km2 and 443k km2 respectively. The two green lines at the bottom show average and 2022 extents when Bering and Okhotsk ice are excluded.  On this basis 2022 Arctic ice was nearly 400k km2 in surplus on May 7, and prior to yesterday, the horizontal line shows little loss of ice extent elsewhere than in the Pacific.

Region	2022127	Day 127 Average	2022-Ave.	2007127	2022-2007
(0) Northern_Hemisphere	13272388	13096082	176306	12954671	317717
(1) Beaufort_Sea	1053640	1059642	-6001	1056022	-2382
(2) Chukchi_Sea	959821	949409	10412	955497	4324
(3) East_Siberian_Sea	1087137	1085912	1225	1081248	5889
(4) Laptev_Sea	897845	892770	5075	870216	27628
(5) Kara_Sea	928813	897443	31370	883059	45754
(6) Barents_Sea	642899	476820	166079	430155	212745
(7) Greenland_Sea	732835	616488	116347	639861	92974
(8) Baffin_Bay_Gulf_of_St._Lawrence	1185073	1140285	44787	1076913	108159
(9) Canadian_Archipelago	854685	845807	8879	845091	9594
(10) Hudson_Bay	1216867	1212411	4456	1192270	24597
(11) Central_Arctic	3248013	3223344	24669	3241053	6960
(12) Bering_Sea	275935	401584	-125649	398914	-122980
(13) Baltic_Sea	14465	13264	1201	10416	4050
(14) Sea_of_Okhotsk	172221	278245	-106023	269684	-97463

The only deficits to average are in Bering and Okhotsk, more than offset by surpluses everywhere else, especially in Barents and Greenland seas, along with Kara and Baffin Bay.  At this point, overall NH sea ice is 88% of last March maximum (15.1M kim2).  All regions are well above 90% of their maxes, except for Barents (81%), Baffin Bay (66%), Bering (33%) and Okhotsk (20%).

 

April 1st Footnote:

It has been a long hard winter, requiring overtime efforts by Norwegian icebreakers like this one:

In addition, cold Spring temperatures led to unusual sightings of Northern creatures:

 

Arctic ice extent changes for the last two weeks are shown in the MASIE animation above. Note that the Pacific basins of Bering and Okhotsk (upper left) melted dramatically.  Meanwhile on the Atlantic side ice persisted, actually growing in Barents and Greenland seas.

The strangeness concerns weirdness in Google Earth Pro treatment of kmz files from MASIE.  Previous I have used these to produce animations like the one below for the month of March.

Today when attempting to do the same for April, this is what was shown.

That is a screen capture since Google Earth could not render an image.  I hope it is just a temporary technical difficulty.  But I can’t help but imagine this depicting some kind of military map with a two-pronged attack by red forces with a single resisting force in red and blue. Is it more virtuous canceling of all things Russian at the expense of scientific inquiry? (The mask with colors was only imposed on the Northern Hemisphere)

The melting effect on NH total ice extents during April is presented in the graph below.

The graph above shows ice extent through April comparing 2022 MASIE reports with the 16-year average, other recent years and with SII.  On average ice extents lost 1.1M km2 during April.  2022 ice extents started slightly lower, then tracked average, ending slightly above average. Both 2021 and 2007 ended  below average, by 200k km2 and 400k km2 respectively. The two green lines at the bottom show average and 2022 extents when Bering and Okhotsk ice are excluded.  On this basis 2022 Arctic was nearly 400k km2 in surplus at end of April.

Region	2022120	Day 120 Average	2022-Ave.	2007120	2022-2007
(0) Northern_Hemisphere	13623874	13507670	116204	13108068	515806
(1) Beaufort_Sea	1070776	1067739	3036	1059189	11587
(2) Chukchi_Sea	963424	955654	7770	949246	14178
(3) East_Siberian_Sea	1087137	1085485	1652	1080176	6961
(4) Laptev_Sea	897845	889961	7884	875661	22184
(5) Kara_Sea	932842	911757	21084	864664	68178
(6) Barents_Sea	654813	547685	107129	396544	258270
(7) Greenland_Sea	777073	640123	136950	644438	132635
(8) Baffin_Bay_Gulf_of_St._Lawrence	1243689	1205315	38374	1147115	96574
(9) Canadian_Archipelago	854685	848564	6121	838032	16653
(10) Hudson_Bay	1240262	1238267	1995	1222074	18188
(11) Central_Arctic	3247307	3229654	17652	3241034	6272
(12) Bering_Sea	334929	482018	-147089	475489	-140560
(13) Baltic_Sea	22696	20622	2074	14684	8012
(14) Sea_of_Okhotsk	294259	381697	-87438	295743	-1484

The only deficits to average are in Bering and Okhotsk, more than offset by surpluses everywhere else, especially in Barents and Greenland seas. 2007 extents were lower by 516k km2 (half a Wadham)

 

April 1st Footnote:

It has been a long hard winter, requiring overtime efforts by Norwegian icebreakers like this one:

In addition, cold Spring temperatures led to unusual sightings of Northern creatures:

 

Previous posts showed 2022 Arctic Ice broke the 15M km2 ceiling in February, followed by a typical small melt in March.  Climatology refers to the March monthly average ice extent as indicative of the annual maximum Arctic ice extent.  The graph above shows that the March monthly average has varied little since 2007, typically around the SII average of 14.7 M km2.  Of course there are regional differences as described later on.

The animation shows ice extent fluctuations during March 2022. Bering Sea (lower left) gained ice over the month, while ice in Okhotsk (higher left) retreated. At the top Kara and Barents seas lost and then gained ice.  Baffin Bay lower right lost ice during March.  The main changes were Baffin losing ~360k km2 of extent and Okhotsk losing ~260k km2.

The effect on NH total ice extents is presented in the graph below.

The graph above shows ice extent through March comparing 2022 MASIE reports with the 16-year average, other recent years and with SII.  Hovering around 15M km2 the first week, 2022 ice extents dropped sharply mid month, then stabilized and at March end matched the average. Both 2020 and 2021 ended nearly 400k km2 below average. The two green lines at the bottom show average and 2022 extents when Okhotsk ice is excluded.  On this basis 2022 Arctic was nearly 400k km2 in surplus, then declined mid month before ending nearly 200k km2 in surplus to average, except for the ice shortage in Okhotsk.

Region	2022090	Day 90 Average	2022-Ave.	2021090	2022-2021
(0) Northern_Hemisphere	14563095	14616765	-53670	14266634	296461
(1) Beaufort_Sea	1070776	1070116	660	1070689	87
(2) Chukchi_Sea	966006	963906	2100	966006	0
(3) East_Siberian_Sea	1087137	1086102	1035	1087137	0
(4) Laptev_Sea	897845	896958	887	897827	18
(5) Kara_Sea	935023	918083	16941	935023	0
(6) Barents_Sea	748326	645014	103311	602392	145934
(7) Greenland_Sea	616239	652388	-36148	620574	-4334
(8) Baffin_Bay_Gulf_of_St._Lawrence	1441014	1400528	40486	1243739	197275
(9) Canadian_Archipelago	854685	852982	1703	854597	88
(10) Hudson_Bay	1260903	1254217	6687	1260903	0
(11) Central_Arctic	3245216	3232275	12941	3192844	52373
(12) Bering_Sea	785874	720525	65348	549939	235935
(13) Baltic_Sea	52068	63446	-11377	33543	18525
(14) Sea_of_Okhotsk	596190	849221	-253031	942085	-345895

The table shows that the large deficit in Okhotsk is only partially offset by surpluses in Bering and Barents Seas.  All other regions show typical extents at end of March

 

April 1st Footnote:

It has been a long hard winter, requiring overtime efforts by Norwegian icebreakers like this one:

In addition, cold March temperatures led to unusual sightings of Northern creatures:

 

A post last month noted that Arctic ice extent in February unusually exceeded 15M km2 (15 Wadhams).  This was despite slower than usual recovery of ice in Sea of Okhotsk.  That early 2022 peak ice extent has passed and will now stand as 2022 annual maximum. One wonders why the large ice deficit in that basin.  The graph below shows the anomaly.

The 2022 cyan line started March above 15M km2, then declined to day 76 (March 17), ~300k km2 lower than the 16 yr. average.  The dark green line shows Arctic ice extent average after Okhotsk is excluded, while the light green is 2022 Arctic extent without Okhotsk. The table below shows that Okhotsk deficit to average on day 76 is 260k km2, almost the entire Arctic deficit.

Region	2022076	Day 76 Average	2022-Ave.	2021076	2022-2021
(0) Northern_Hemisphere	14641084	14935497	-294413	14769906	-128822
(1) Beaufort_Sea	1070776	1070247	529	1070689	87
(2) Chukchi_Sea	966006	965877	129	966006	0
(3) East_Siberian_Sea	1087137	1087107	30	1087120	17
(4) Laptev_Sea	897845	897837	8	897827	18
(5) Kara_Sea	905846	923576	-17730	935006	-29160
(6) Barents_Sea	554036	648194	-94158	849221	-295185
(7) Greenland_Sea	572046	618979	-46934	601423	-29377
(8) Baffin_Bay_Gulf_of_St._Lawrence	1784542	1534462	250080	1288815	495727
(9) Canadian_Archipelago	854685	853020	1665	854597	88
(10) Hudson_Bay	1260691	1258149	2542	1260471	220
(11) Central_Arctic	3153037	3223013	-69976	3222708	-69671
(12) Bering_Sea	729277	755358	-26081	547775	181502
(13) Baltic_Sea	59785	81419	-21634	62626	-2841
(14) Sea_of_Okhotsk	739183	998164	-258981	1117615	-378432

Most places are close to average, with a large surplus in Baffin Bay offsetting small deficits elsewhere.  The exception is Okhotsk making up most of the total deficit to average, and even a larger deficit to last year

IOW, had Okhotsk extent been average on day 60 (1.08M km2) instead of 852k km2, the surplus would have been even higher.  So why was ice missing in Okhotsk this year?

Firstly, the animation above shows that Okhotsk (and also Bering) sea ice is quite variable year over year. The MASIE record for day 60 shows Okhotsk at 880k km2 in 2006, up to 1230k km2 in 2012, down to 770k km2 in 2015, up to 1080k km2 in 2018, down to  850k km2 in 2022. Notice Okhotsk 2022 is quite similar to 2015, while Bering is about average this year.  What causes these fluctuations on annual, decadal and longer time scales?

The answer illustrates the complexity of natural factors interacting to produce climatic patterns we observe and measure. In Okhotsk in particular, and in the Arctic generally, changes in ice extents are a function of the 3 Ws: Water, Wind and Weather. More specifically, water changes in temperature (SST) and salinity (SSS); wind changes with changes in sea level pressures (SLP); and stormy weather varies between cyclonic and anticyclonic regimes. Below is discussion of these natural mechanisms.

Background on Okhotsk Sea

NASA describes Okhotsk as a Sea and Ice Factory. Excerpts in italics with my bolds.

The Sea of Okhotsk is what oceanographers call a marginal sea: a region of a larger ocean basin that is partly enclosed by islands and peninsulas hugging a continental coast. With the Kamchatka Peninsula, the Kuril Islands, and Sakhalin Island partly sheltering the sea from the Pacific Ocean, and with prevailing, frigid northwesterly winds blowing out from Siberia, the sea is a winter ice factory and a year-round cloud factory.

The region is the lowest latitude (45 degrees at the southern end) where sea ice regularly forms. Ice cover varies from 50 to 90 percent each winter depending on the weather. Ice often persists for nearly six months, typically from October to March. Aside from the cold winds from the Russian interior, the prodigious flow of fresh water from the Amur River freshens the sea, making the surface less saline and more likely to freeze than other seas and bays.

Map of the Sea of Okhotsk with bottom topography. The 200- and 3000-m isobars are indicated by thin and thick solid lines, respectively. A box denotes the enlarged portion in Figure 5. White shading indicates sea-ice area (ice concentration ⩾30%) in February averaged for 2003–11; blue shading indicates open ocean area. Ice concentration from AMSR-E is used. Color shadings indicate cumulative ice production in coastal polynyas during winter (December–March) averaged from the 2002/03 to 2009/10 seasons (modified from Nihashi and others, 2012, 2017). The amount is indicated by the bar scale. Source: Cambridge Core

Basics of Weather and Ice Dynamics

Wind directions are named by which point on the compass the prevailing wind hits you in the face.  Thus, a southerly wind comes from the south toward the north, typically bringing warmer air north, and displacing colder northern air.

Winds arise from differences in surface pressures. Above every square inch on the surface of the Earth is 14.7 pounds of air. That means air exerts 14.7 pounds per square inch (psi) of pressure at Earth’s surface. High in the atmosphere, air pressure decreases.

Pressure varies from day to day at the Earth’s surface – the bottom of the atmosphere. This is, in part, because the Earth is not equally heated by the Sun. Areas where the air is warmed often have lower pressure because the warm air rises. These areas are called low pressure systems. Places where the air pressure is high, are called high pressure systems.

A low pressure system has lower pressure at its center than the areas around it. Winds blow towards the low pressure, and the air rises in the atmosphere where they meet. As the air rises, the water vapor within it condenses, forming clouds and often precipitation. Because of Earth’s spin and the Coriolis effect, winds of a low pressure system swirl counterclockwise north of the equator and clockwise south of the equator. This is called cyclonic flow. On weather maps, a low pressure system is labeled with red L.

A high pressure system has higher pressure at its center than the areas around it. Winds blow away from high pressure. Swirling in the opposite direction from a low pressure system, the winds of a high pressure system rotate clockwise north of the equator and counterclockwise south of the equator. This is called anticyclonic flow. Air from higher in the atmosphere sinks down to fill the space left as air is blown outward. On a weather map, you may notice a blue H, denoting the location of a high pressure system.

When the suns shines on land the air is warmed and rises. And because the earth is rotating, an upward spiral forms. Additionally, over wetlands and the oceans there is evaporation, which also rises, H2O being lighter than N2 or O2. When the water is warmer, the rising air intensifies and resulting in a lower pressure than surrounding areas.  Arctic cyclones disrupt drift ice, creating more open water, and impede freezing.  Arctic anticyclones (HP cells) facilitate cooling and freezing.

The vertical direction of wind motion is typically very small (except in thunderstorm updrafts) compared to the horizontal component, but is very important for determining the day to day weather. Rising air will cool, often to saturation, and can lead to clouds and precipitation. Sinking air warms causing evaporation of clouds and thus fair weather.

The closer the isobars are drawn together the quicker the air pressure changes. This change in air pressure is called the “pressure gradient”. Pressure gradient is just the difference in pressure between high- and low-pressure areas.

The Okhotsk Sea Ice Connection

Toyoda et al. (2022) explain in their paper Sea ice variability along the Okhotsk coast of Hokkaido based on long-term JMA meteorological observatory data.  Excerpts in italics with  my bolds.

Abstract

Long-term sea ice observation data at the Japan Meteorological Agency observatories along the
Okhotsk coast of Hokkaido were analyzed. The observations at the Abashiri Local Meteorological
Observatory largely explained the variations at other sites along much of the Okhotsk coast on a time scale longer than a few days. Interannually, variations of the maximum sea ice areas in the whole and southern Sea of Okhotsk were largely reflected in the yearly accumulated sea ice concentration (SIC) and sea ice duration variations at the observatories.

A comparison with several indices for the North Pacific climate variability suggested that the North Pacific Index (NPI) is a robust indicator of the recent (after the 1980s) sea ice variations in the Sea of Okhotsk on a decadal time scale. Specifically:

♦  variations in the first sea ice appearance date at the observatories resulted from variations in the Aleutian Low with meridional wind anomalies over the Sea of Okhotsk and the air temperature around Japan in January;

♦  variations in the final disappearance date resulted from the Aleutian Low variations, and,

♦  the resulting sea ice cover variations in the Sea of Okhotsk except for the Siberian coast affected the air temperatures in April. These factors influenced the sea ice duration.

A strong linkage was found between variations in the local sea ice (along the Hokkaido coast) and large-scale fields, which will help improve our understanding of the sea ice extent and retreat variability over the Sea of Okhotsk and its linkage to the North Pacific climate variability.

Among several climate indices, the NPI is a robust indicator of recent (after the 1980s) sea ice
variations in the Sea of Okhotsk. We also examined the differences between the start and end date variations, which determine the durations. Variations in the start date at the Okhotsk coast sites resulted from the variations in the Aleutian Low strength, the air temperature around Japan in January, and partly the SST along the Soya warm current in December. Variations in the end date resulted from the Aleutian Low variations; the sea ice cover variations affected the air temperatures over the Sea of Okhotsk in April, in contrast to the sea ice cover variations in January resulting from the air temperature variations.

Sea Ice Tourism from Hokkaido, Japan

Taking a boat trip from Hokkaido Island to see Okhotsk drift ice is a big tourist attraction, as seen in the short video below.  Al Gore had them worried back then, but hopefully not now.

Previous posts reported how Arctic ice was growing faster than average as well as last year.  Remarkably, several regions have already exceeded their maximum ice extents last March, and overall, Arctic ice is 98% of 2021 maximum with six weeks of freezing season remaining.

The animation shows ice growing the second half of January, notably reaching 1.32M km2 in Baffin Bay, right center, exceeding 2021 max.  Greenland Sea, center top, added 144k km2 to reach 710k km2, also greater than last year’s max.  And at bottom left Bering Sea reached 741k km2, 116% of last years max.

This year began with a surplus and ended January still 230k km2 higher.  The gap over 2021 is 465k km2, nearly half a Wadham. SII dipped and then rose to match MASIE before a drop yesterday.

Region	2022031	Day 31 Average	2022-Ave.	2021031	2022-2021
(0) Northern_Hemisphere	14599079	14368396	230683	14133494	465586
(1) Beaufort_Sea	1070776	1070282	494	1070689	87
(2) Chukchi_Sea	966006	965968	38	966006	0
(3) East_Siberian_Sea	1087137	1087049	89	1087120	17
(4) Laptev_Sea	897827	897821	6	897827	0
(5) Kara_Sea	934844	917081	17763	934952	-108
(6) Barents_Sea	695583	572672	122910	690363	5220
(7) Greenland_Sea	724418	594443	129976	621098	103321
(8) Baffin_Bay_Gulf_of_St._Lawrence	1322799	1336538	-13738	1008582	314217
(9) Canadian_Archipelago	854685	853253	1433	854597	88
(10) Hudson_Bay	1260903	1260753	151	1260471	432
(11) Central_Arctic	3226420	3210376	16045	3203312	23108
(12) Bering_Sea	741202	650072	91130	545486	195717
(13) Baltic_Sea	62895	64264	-1369	52787	10108
(14) Sea_of_Okhotsk	720277	826161	-105884	900121	-179843

The table shows that surpluses in Barents, Greenland and Bering seas more than offset a deficit to average in Okhotsk.  In the latter case, ice has finally begun to build up toward a normal extent for this period. With an overall extent of 14.6M km2, prospects are good for maxing higher than 15M km2 by mid March.

 

 

The animation focuses on the two Pacific basins since most of the ice action is seen there.  The seesaw refers to a frequent observation that Bering and Okhotsk Seas often alternate growing and receding ice extents during both melting and freezing seasons.  This month Bering on the right is seen adding ice steadily from 387k km2 to 664k km2, now at 104% of its last March maximum. Meanwhile Okhotsk on the left starts at 466k km2, waffles back and forth, growing to 554k km2 before retreating to match the beginning.

The graph below shows daily ice extents for January 2022 compared to 16 year averages, and some years of note.

The black line shows during January on average (2006 to 2021 inc.) Arctic ice extents increased ~1.3M km2 from ~13.1M km2 up to ~13.4M km2.  The 2022 cyan MASIE line started the year 261k km2 above average and on day 15 retained a surplus of 84k km2.  The Sea Ice Index in orange (SII from NOAA) started with the same deficit, then lagged behind in the first two weeks, before ending yesterday the same as MASIE. 2021 and 2020 started below average but made up most of the difference by mid month.

Why is this important?  All the claims of global climate emergency depend on dangerously higher temperatures, lower sea ice, and rising sea levels.  The lack of additional warming is documented in a post UAH Confirms Global Warming Gone End of 2021.

The lack of acceleration in sea levels along coastlines has been discussed also.  See Inside the Sea Level Scare Machine

Also, a longer term perspective is informative:

The table below shows the distribution of Sea Ice on day 015 across the Arctic Regions, on average, this year and 2021.

Region	2022015	Day 15 Average	2022-Ave.	2021015	2022-2021
(0) Northern_Hemisphere	13851226	13767662	83564	13709295	141931
(1) Beaufort_Sea	1070776	1070247	529	1070689	87
(2) Chukchi_Sea	966006	965889	117	966006	0
(3) East_Siberian_Sea	1087137	1087131	6	1087120	17
(4) Laptev_Sea	897827	897837	-10	897827	0
(5) Kara_Sea	935023	908782	26242	860326	74697
(6) Barents_Sea	710507	509307	201200	479880	230628
(7) Greenland_Sea	584670	600334	-15664	649983	-65313
(8) Baffin_Bay_Gulf_of_St._Lawrence	1084523	1158194	-73671	1060873	23650
(9) Canadian_Archipelago	854685	853209	1476	854597	88
(10) Hudson_Bay	1260903	1254880	6024	1260471	432
(11) Central_Arctic	3199791	3209964	-10173	3183652	16140
(12) Bering_Sea	664148	535155	128993	503676	160473
(13) Baltic_Sea	44692	42101	2591	31534	13157
(14) Sea_of_Okhotsk	466605	629910	-163305	765767	-299162

The overall surplus to average is 84k km2, (0.6%).  Note large surpluses of ice in Barents and Bering Seas. The main deficit to average is in Sea of Okhotsk, as noted at the top.

Illustration by Eleanor Lutz shows Earth’s seasonal climate changes. If played in full screen, the four corners present views from top, bottom and sides. It is a visual representation of scientific datasets measuring Arctic ice extents.

Remarkable Arctic ice recovery continued in December as seen in the animation below:

The month of December 2021 shows Hudson Bay (lower right) starting with only some shore ice and ending virtually ice covered, adding in that basin 925K km2, nearly a full Wadham. Just above Hudson, you can see the Gulf of St. Lawrence icing over, and Baffin Bay adding ice as well, adding 257k km2 to the total.

At the extreme left Okhotsk Sea also starts with shore ice and grows 435k km2, reaching down to Japan.  At the top Kara freezes over and Barents and Greenland Seas add ice to their margins. The graph below shows the December ice recovery

Note the average year adds 2M km2 and 2021 exceeded that by ~200k km2, maintaining its surplus position.  Other years starting far behind drew closer to average by the end.  SII has not yet reported its estimate of day 365.

The table below shows year-end ice extents in the various Arctic basins compared to the 14-year averages and some recent years.

Region	2021365	Day 365 Average	2021-Ave.	2020365	2021-2020
(0) Northern_Hemisphere	13340119	13052148	287971	12765491	574628
(1) Beaufort_Sea	1070776	1070324	452	1070689	87
(2) Chukchi_Sea	966006	964420	1586	966006	0
(3) East_Siberian_Sea	1087137	1087132	5	1087120	17
(4) Laptev_Sea	897827	897841	-14	897827	0
(5) Kara_Sea	932872	883615	49256	879232	53640
(6) Barents_Sea	653611	423352	230260	371122	282489
(7) Greenland_Sea	620509	579341	41168	592839	27671
(8) Baffin_Bay_Gulf_of_St._Lawrence	873269	1003682	-130413	867509	5760
(9) Canadian_Archipelago	854685	853276	1409	854597	88
(10) Hudson_Bay	1245910	1236600	9311	1257919	-12009
(11) Central_Arctic	3221247	3203619	17628	3159881	61366
(12) Bering_Sea	358002	408726	-50724	249522	108481
(13) Baltic_Sea	61428	30674	30755	7986	53443
(14) Sea_of_Okhotsk	478257	382234	96023	479972	-1715

This year’s ice extent is almost 300k km2 or 2% above average.  Only Baffin Bay and Bering Sea are in deficit to average, more than offset by surpluses elsewhere, especially in Kara, Barents and Okhotsk seas.

Comparing Arctic Ice at End of Years

At  the bottom is a discussion of statistics on year-end Arctic Sea Ice extents.  The values are averages of the last five days of each year.  End of December is a neutral point in the melting-freezing cycle, midway between September minimum and March maximum extents.

Background from Previous Post Updated to Year-End 2021

Some years ago reading a thread on global warming at WUWT, I was struck by one person’s comment: “I’m an actuary with limited knowledge of climate metrics, but it seems to me if you want to understand temperature changes, you should analyze the changes, not the temperatures.” That rang bells for me, and I applied that insight in a series of Temperature Trend Analysis studies of surface station temperature records. Those posts are available under this heading. Climate Compilation Part I Temperatures

This post seeks to understand Arctic Sea Ice fluctuations using a similar approach: Focusing on the rates of extent changes rather than the usual study of the ice extents themselves. Fortunately, Sea Ice Index (SII) from NOAA provides a suitable dataset for this project. As many know, SII relies on satellite passive microwave sensors to produce charts of Arctic Ice extents going back to 1979.  The current Version 3 has become more closely aligned with MASIE, the modern form of Naval ice charting in support of Arctic navigation. The SII User Guide is here.

There are statistical analyses available, and the one of interest (table below) is called Sea Ice Index Rates of Change (here). As indicated by the title, this spreadsheet consists not of monthly extents, but changes of extents from the previous month. Specifically, a monthly value is calculated by subtracting the average of the last five days of the previous month from this month’s average of final five days. So the value presents the amount of ice gained or lost during the present month.

These monthly rates of change have been compiled into a baseline for the period 1980 to 2010, which shows the fluctuations of Arctic ice extents over the course of a calendar year. Below is a graph of those averages of monthly changes during the baseline period. Those familiar with Arctic Ice studies will not be surprised at the sine wave form. December end is a relatively neutral point in the cycle, midway between the September Minimum and March Maximum.

The graph makes evident the six spring/summer months of melting and the six autumn/winter months of freezing.  Note that June-August produce the bulk of losses, while October-December show the bulk of gains. Also the peak and valley months of March and September show very little change in extent from beginning to end.

The table of monthly data reveals the variability of ice extents over the last 4 decades.

The values in January show changes from the end of the previous December, and by summing twelve consecutive months we can calculate an annual rate of change for the years 1979 to 2021.

 

As many know, there has been a decline of Arctic ice extent over these 40 years, averaging 70k km2 per year. But year over year, the changes shift constantly between gains and losses.

Moreover, it seems random as to which months are determinative for a given year. For example, much ado was printed about June and July 2021 melting faster than expected resulting in higher losses of ice extents. But then the final 3 months of 2021 more than made up for those summer losses

As it happens in this dataset, October has the highest rate of adding ice. The table below shows the variety of monthly rates in the record as anomalies from the 1980-2010 baseline. In this exhibit a red cell is a negative anomaly (less than baseline for that month) and blue is positive (higher than baseline).

 

Note that the  +/ –  rate anomalies are distributed all across the grid, sequences of different months in different years, with gains and losses offsetting one another.  Yes, June 2021 lost more ice than the baseline, but about the same as 2017, and not as much as 2012. The gains in Oct.-Dec. 2021 were ~1M km2 above baseline, but were exceeded by the same months in 2019 and 2020.  The bottom line presents the average anomalies for each month over the period 1979-2021.  Note the rates of gains and losses mostly offset, and the average of all months in the bottom right cell is virtually zero.

A final observation: The graph below shows the Yearend Arctic Ice Extents for the last 32 years.

 

 

Year-end Arctic ice extents (last 5 days of December) show three distinct regimes: 1988-1998, 1998-2010, 2010-2021. The average year-end extent 1989-2010 is 13.4M km2. In the last decade, 2011 was 13.0M km2, and six years later, 2017 was 12.3M km2. 2021 rose back to 13.06  So for all the the fluctuations, the net is zero, or a gain from 2010. Talk of an Arctic ice death spiral is fanciful.

These data show a noisy, highly variable natural phenomenon. Clearly, unpredictable factors are in play, principally water structure and circulation, atmospheric circulation regimes, and also incursions and storms. And in the longer view, today’s extents are not unusual.

 

 

Illustration by Eleanor Lutz shows Earth’s seasonal climate changes. If played in full screen, the four corners present views from top, bottom and sides. It is a visual representation of scientific datasets measuring Arctic ice extents.