Feb. 2021 Polar Vortex Hits Okhotsk Ice

 

Update Feb. 19, 2021 to previous post

This update is to note a dramatic effect on Okhotsk Sea ice coincidental with the Polar Vortex event that froze Texas and other midwestern US states.  When Arctic air extends so far south due to the weak and wavy vortex, warmer air replaces the icy air in Arctic regions.  In this case, the deficits to sea ice extent appear mostly in the Sea of Okhotsk in the Pacific.

The graph below shows a sharp drop in ice extent the last three days.

A closer look into the regions shows that Okhotsk peaked at 1.1M km2 on day 37, and lost 217k km2 down to 0.9M km2 yesterday.  That loss along with Bering flat extent makes up 70% of the present deficit to average.

Some comments from Dr. Judah Cohen Feb. 15 from his AER blog Arctic Oscillation and Polar Vortex Analysis and Forecasts  Excerpts in italics with my bolds.

I have been writing how the stratospheric PV disruption that has been so influential on our weather since mid-January has been unusual and perhaps even unique in the observational record, so I guess then it should be no surprise that it’s ending is also highly unusual. I was admittedly skeptical, but it does seem that the coupling between the stratospheric PV and the tropospheric circulation is about to come to an abrupt end.

The elevated polar cap geopotential height anomalies (PCHs) related to what I like to refer to the third and final PV disruption at the end of January/early February quickly propagates to the surface and even amplifies, peaking this past weekend. And as I have argued, it is during spikes in PCH when severe winter is most likely across the NH mid-latitudes, as demonstrated in Cohen et al. (2018).

But rather than the typical gradual influence from the stratospheric PV disruption over many weeks, maybe akin to the drip, drip, drip of a leaky faucet, the entire signal dropped all at once like an anchor. This also likely contributed to the severity of the current Arctic outbreak in the Central US that is generational and even historical in its severity. But based on the forecast the PV gave all it had all at once, and the entire troposphere-stratosphere-troposphere coupling depicted in Figure ii is about to abruptly end in the next few days.

I am hesitant to bring analogs before 2000 but the extreme cold in Texas did remind me of another winter that brought historic Arctic outbreaks including cold to Texas – January 1977. It does appear that the downward influence from the stratospheric PV to the surface came to an abrupt end at the end of January 1977 . . . Relative to normal, January 1977 was the coldest month for both Eurasia and the US when stratosphere-troposphere coupling was active. But the relative cold did persist in both the Eastern US and northern Eurasia in February post the stratosphere-troposphere coupling. By March the cold weather in the Eastern US was over but persisted for northern Eurasia.

See also No, CO2 Doesn’t Drive the Polar Vortex

Background from Previous Post

In January, most of the Arctic ocean basins are frozen over, and so the growth of ice extent slows down.  According to SII (Sea Ice Index) January on average adds 1.3M km2, and this month it was 1.4M.  (background is at Arctic Ice Year-End 2020).  The few basins that can grow ice this time of year tend to fluctuate and alternate waxing and waning, which appears as a see saw pattern in these images.

Two weeks into February Arctic ice extents are growing faster than the 14-year average, such that they are approaching the mean.  The graph below shows the ice recovery since mid-January for 2021, the 14-year average and several recent years.

The graph shows mid January a small deficit to average, then slow 2021 growth for some days before picking up the pace in the latter weeks.  Presently extents are slightly (1%) below average, close to 2019 and 2020 and higher than 2018.

February Ice Growth Despite See Saws in Atlantic and Pacific

As noted above, this time of year the Arctic adds ice on the fringes since the central basins are already frozen over.  The animation above shows Barents Sea on the right (Atlantic side) grew in the last two weeks by 175k km2 and is now 9% greater than the maximum last March.  Meanwhile on the left (Pacific side)  Bering below and Okhotsk above wax and wane over this period. Okhotsk is seen growing 210k km2 the first week, and giving half of it back the second week.  Bering waffles up and down ending sightly higher in the end.

The table below presents ice extents in the Arctic regions for day 44 (Feb. 13) compared to the 14 year average and 2018.

Region 2021044 Day 044 Average 2021-Ave. 2018044 2021-2018
 (0) Northern_Hemisphere 14546503 14678564 -132061 14140166 406337
 (1) Beaufort_Sea 1070689 1070254 435 1070445 244
 (2) Chukchi_Sea 966006 965691 315 965971 35
 (3) East_Siberian_Sea 1087120 1087134 -14 1087120 0
 (4) Laptev_Sea 897827 897842 -15 897845 -18
 (5) Kara_Sea 934988 906346 28642 874714 60274
 (6) Barents_Sea 837458 563224 274235 465024 372434
 (7) Greenland_Sea 645918 610436 35482 529094 116824
 (8) Baffin_Bay_Gulf_of_St._Lawrence 1057623 1487547 -429924 1655681 -598058
 (9) Canadian_Archipelago 854597 853146 1451 853109 1489
 (10) Hudson_Bay 1260471 1260741 -270 1260838 -367
 (11) Central_Arctic 3206263 3211892 -5630 3117143 89120
 (12) Bering_Sea 559961 674196 -114235 319927 240034
 (13) Baltic_Sea 116090 94341 21749 76404 39686
 (14) Sea_of_Okhotsk 1027249 930357 96892 911105 116144
 (15) Yellow_Sea 9235 28237 -19002 33313 -24078
 (16) Cook_Inlet 223 11137 -10914 11029 -10806

The table shows that Bering defict to average is offset by surplus in Okhotsk.  Baffin Bay show the largest deficit, mostly offset by surpluses in Barents, Kara and Greenland Sea.

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.

Feb. 2021 Arctic Ice Stays the Course

In January, most of the Arctic ocean basins are frozen over, and so the growth of ice extent slows down.  According to SII (Sea Ice Index) January on average adds 1.3M km2, and this month it was 1.4M.  (background is at Arctic Ice Year-End 2020).  The few basins that can grow ice this time of year tend to fluctuate and alternate waxing and waning, which appears as a see saw pattern in these images.

Two weeks into February Arctic ice extents are growing faster than the 14-year average, such that they are approaching the mean.  The graph below shows the ice recovery since mid-January for 2021, the 14-year average and several recent years.

The graph shows mid January a small deficit to average, then slow 2021 growth for some days before picking up the pace in the latter weeks.  Presently extents are slightly (1%) below average, close to 2019 and 2020 and higher than 2018.

February Ice Growth Despite See Saws in Atlantic and Pacific

As noted above, this time of year the Arctic adds ice on the fringes since the central basins are already frozen over.  The animation above shows Barents Sea on the right (Atlantic side) grew in the last two weeks by 175k km2 and is now 9% greater than the maximum last March.  Meanwhile on the left (Pacific side)  Bering below and Okhotsk above wax and wane over this period. Okhotsk is seen growing 210k km2 the first week, and giving half of it back the second week.  Bering waffles up and down ending sightly higher in the end.

The table below presents ice extents in the Arctic regions for day 44 (Feb. 13) compared to the 14 year average and 2018.

Region 2021044 Day 044 Average 2021-Ave. 2018044 2021-2018
 (0) Northern_Hemisphere 14546503 14678564 -132061 14140166 406337
 (1) Beaufort_Sea 1070689 1070254 435 1070445 244
 (2) Chukchi_Sea 966006 965691 315 965971 35
 (3) East_Siberian_Sea 1087120 1087134 -14 1087120 0
 (4) Laptev_Sea 897827 897842 -15 897845 -18
 (5) Kara_Sea 934988 906346 28642 874714 60274
 (6) Barents_Sea 837458 563224 274235 465024 372434
 (7) Greenland_Sea 645918 610436 35482 529094 116824
 (8) Baffin_Bay_Gulf_of_St._Lawrence 1057623 1487547 -429924 1655681 -598058
 (9) Canadian_Archipelago 854597 853146 1451 853109 1489
 (10) Hudson_Bay 1260471 1260741 -270 1260838 -367
 (11) Central_Arctic 3206263 3211892 -5630 3117143 89120
 (12) Bering_Sea 559961 674196 -114235 319927 240034
 (13) Baltic_Sea 116090 94341 21749 76404 39686
 (14) Sea_of_Okhotsk 1027249 930357 96892 911105 116144
 (15) Yellow_Sea 9235 28237 -19002 33313 -24078
 (16) Cook_Inlet 223 11137 -10914 11029 -10806

The table shows that Bering defict to average is offset by surplus in Okhotsk.  Baffin Bay show the largest deficit, mostly offset by surpluses in Barents, Kara and Greenland Sea.

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.

2021 Arctic Ice Seesaw

In January, most of the Arctic ocean basins are frozen over, and so the growth of ice extent slows down.  According to SII (Sea Ice Index) January on average adds 1.3M km2, and this month it was 1.4M.  (background is at Arctic Ice Year-End 2020).  The few basins that can grow ice this time of year tend to fluctuate and alternate waxing and waning, which appears as a see saw pattern in these images.

Here is the Atlantic seesaw with Barents and Baffin.

The animation above shows the Atlantic side with Barents on the left almost doubling in the last 3 weeks, from 365k km2 ice extent to 690k km2 yesterday (88% of last March maximmum).  Meanwhile Greenland Sea in the center between Iceland and Greenland started with 708k km2 and was 621k km2 yesterday.  Maximum ice extent in this basin was 783k km2 last year.  Baffin Bay below and to the right of Greenland waffles up and down a bit with little change (from 993k km2 to 1000k km2 with last year’s max 1550k).

And here is the Pacific seesaw with Bering and Okhotsk.

The most dramatic teeter-totter comes in the two Pacific basins of Bering Sea and Sea of Okhotsk, shown in the animation above. Okhotsk on the left in 3 weeks grew ice extent from 652k km2 to 900k yesterday, nearly 80% of 2020 max of 1140k km2.  Yet just a few days ago, Okhotsk was at 972k.  Meanwhile Bering Sea is seen fluctuating back and forth while gaining extent from 360k km2 up to 545k, 67% of last year’s max.

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 graph shows the 14-year average gain for January is 1.3M km2.  2020 matched the average while this and other recent years were lower.  SII shows lower extents most of the month before aligning with MASIE at the end. Presently 2021 is ~290k km2 or 2% deficit to average, or lagging about a week behind.

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 Building Ice Inventory Mid January

At this point in the Arctic refreezing phase, LIFO inventory accounting comes into play.  Last-In, First-out is one accepted way to price the value of a company’s inventory.  For Arctic ice, it means that basins that are last to freeze over in winter are the first to melt out in the summer.  For example, in Mid January 2021, total NH ice extent is 91% of last March maximum, so most basins have long been covered with ice.  The last 9% will be added in four places (present % of max is noted):

Bering Sea        62%
Okhotsk Sea     70%
Barents Sea      58%
Baffin Bay         66%

In the Pacific animation above, Bering on the right adds ice extent from 261k km2 to 513k km2 since Jan. 1, while Okhotsk goes from 500k km2 to 800k km2.  Together they will likely add ~650k km2 more by March maximum.  

On the Atlantic side, Barents Sea added only ~100k km2 so far in January.  More interesting on the right side is the Baltic Sea quadrupled from 9K km2 to 42k km2.  While the Baltic extent is not large by comparison, it is already 38% greater than last March maximum, so that is surprising.

Normally, ice in the Yellow Sea is insignificant, but this year is different.  Perhaps you saw reports like this one from gcaptain Sea Ice Slows Ships In North China Ports  Excerpts in italics with my bolds.

By Muyu Xu and Chen Aizhu (Reuters) – Chinese ports and marine safety authorities are on high alert as an expansion of sea ice makes it tougher for ships to berth and discharge at key energy product import terminals along the coast of northern Bohai Bay.

A cold wave sweeping the northern hemisphere has plunged temperatures across China to their lowest in decades, boosting demand for power and fuel to historic highs in the world’s largest energy consumer.

Bohai Bay appears in the upper right corner, with Beijing nearby. Yellow Sea extent doubled in January up to 28,000 km2, which is twice the maximum last March.

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

Bering Sea Ice is Highly Variable

The animation above shows Bering Sea ice extents at April 2 from 2007 to 2020.  The large fluctuation is evident, much ice in 2012 -13 and almost none in 2018, other years in between.  Given the alarmist bias, it’s no surprise which two years are picked for comparison:

Source: Seattle Times ‘We’ve fallen off a cliff’: Scientists have never seen so little ice in the Bering Sea in spring.

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 not now.

Drift ice in Okhotsk Sea at sunrise.

Arctic Ice Year-End 2020

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

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 2019.

As many know, there has been a decline of Arctic ice extent over these 40 years, averaging 40k 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 has been printed about October 2020 being slower than expected to refreeze and add ice extents. 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, October 2020 recorded a lower than average gain, but higher than 2016. The loss in July 2020 was the largest of the year, during the hot Siberian summer.  Note November 2020 ice gain anomaly exceeded the October deficit anomaly by more than twice as much.  December added more surplus so that the anomaly for the year was nothing. The bottom line presents the average anomalies for each month over the period 1979-2020.  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 30 years.

Note: SII daily extents file does not provide complete values prior to 1988.

Year-end Arctic ice extents (last 5 days of December) show three distinct regimes: 1989-1998, 1998-2010, 2010-2019. The average year-end extent 1989-2010 is 13.4M km2. In the last decade, 2009 was 13.0M km2, and ten years later, 2019 was 12.8M km2. So for all the the fluctuations, the net loss was 200k km2, or 1.5%. 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.

 

Arctic Freezing Fast Mid-Dec. 2020

 

As noted in a previous post, alarms were raised over slower than average Arctic refreezing in October.  Those fears were laid to rest firstly when ice extents roared back in November, and now with the Arctic freezing fast in December. The image above shows the ice gains over the last two weeks, from Dec. 5 to 17, 2020.  In November, 3.5 Wadhams of sea ice were added during the month.  (The metric 1 Wadham = 1 M km2 comes from the professor’s predictions of an ice-free Arctic, meaning less than 1 M km2 extent). So far in December a further 1.9 Wadhams have been added with another two weeks to go in 2020.

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 2019.

As many know, there has been a decline of Arctic ice extent over these 40 years, averaging 40k 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 has been printed about October 2020 being slower than expected to refreeze and add ice extents. 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, October 2020 recorded a lower than average gain, but higher than 2016. The loss in July 2020 was the largest of the year, during the hot Siberian summer.  Note November 2020 ice gain anomaly exceeded the October deficit anomaly by more than twice as much.  The bottom line presents the average anomalies for each month over the period 1979-2020.  Note the rates of gains and losses mostly offset, and the average of all months in the bottom right cell is virtually zero.

Combining the months of October and November shows 2020 828k km2 more ice than baseline for the two months and matching 2019 ice recovery.

The average December adds 2M km2 of sea ice according to SII dataset, and in the first 17 days of December 2020 ice increased by 1.9M km2, with 2 weeks of futher freezing to come.

A final observation: The graph below shows the Yearend Arctic Ice Extents for the last 30 years.

Note: SII daily extents file does not provide complete values prior to 1988.

Year-end Arctic ice extents (last 5 days of December) show three distinct regimes: 1989-1998, 1998-2010, 2010-2019. The average year-end extent 1989-2010 is 13.4M km2. In the last decade, 2009 was 13.0M km2, and ten years later, 2019 was 12.8M km2. So for all the the fluctuations, the net loss was 200k km2, or 1.5%. 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.

Arctic Ice Fears Erased in November

As noted in a previous post, alarms were raised over slower than average Arctic refreezing in October.  Those fears are now laid to rest by ice extents roaring back in November.  The image above shows the ice gains completed from October 31 to November 30, 2020. In fact 3.5 Wadhams of sea ice were added during the month.  (The metric 1 Wadham = 1 M km2 comes from the professor’s predictions of an ice-free Arctic, meaning less than 1 M km2 extent)

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 2019.

As many know, there has been a decline of Arctic ice extent over these 40 years, averaging 40k 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 has been printed about October 2020 being slower than expected to refreeze and add ice extents. 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, October 2020 recorded a lower than average gain, but higher than 2016. The loss in July 2020 was the largest of the year, during the hot Siberian summer.  Note November 2020 ice gain anomaly exceeded the October deficit anomaly by more than twice as much.  The bottom line presents the average anomalies for each month over the period 1979-2020.  Note the rates of gains and losses mostly offset, and the average of all months in the bottom right cell is virtually zero.

Combining the months of October and November shows 2020 828k km2 more ice than baseline for the two months and matching 2019 ice recovery.

A final observation: The graph below shows the Yearend Arctic Ice Extents for the last 30 years.

Note: SII daily extents file does not provide complete values prior to 1988.

Year-end Arctic ice extents (last 5 days of December) show three distinct regimes: 1989-1998, 1998-2010, 2010-2019. The average year-end extent 1989-2010 is 13.4M km2. In the last decade, 2009 was 13.0M km2, and ten years later, 2019 was 12.8M km2. So for all the the fluctuations, the net loss was 200k km2, or 1.5%. 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.

Arctic Adds 3 Wadhams of Ice in November (so far)

After concerns over lackluster ice recovery in October, November is seeing ice roaring back.  The image above shows the last 3 weeks adding 3 M km2 of sea ice.  (The metric 1 Wadham = 1 M km2 comes from the professor’s predictions of an ice-free Arctic, meaning less than 1 M km2 extent) The Russian shelf seas on the left filled with ice early on.  On the CanAm side, Beaufort at the bottom center is iced over, Canadian Archipelago (center right) is frozen, and Baffin Bay is filling from the north down.  Hudson Bay (far right) first grew fast ice around the edges, and is now half iced over.  A background post is reprinted below, showing that in just 23 days, 2020 has added 3.1 M km2, 50% more than an average 30-day November.

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.

Table 1 Monthly Arctic Ice rates of Extent Changes in M km2. Months with losses in pink, months with gains in blue.

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 2019.

As many know, there has been a decline of Arctic ice extent over these 40 years, averaging 40k 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 has been printed about October 2020 being slower than expected to refreeze and add ice extents. 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, October 2020 recorded a lower than average gain, but higher than 2016. The loss in July 2020 was the largest of the year, during the hot Siberian summer.  The bottom line presents the average anomalies for each month over the period 1979-2020.  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 30 years.

Note: SII daily extents file does not provide complete values prior to 1988.

Year-end Arctic ice extents (last 5 days of December) show three distinct regimes: 1989-1998, 1998-2010, 2010-2019. The average year-end extent 1989-2010 is 13.4M km2. In the last decade, 2009 was 13.0M km2, and ten years later, 2019 was 12.8M km2. So for all the the fluctuations, the net loss was 200k km2, or 1.5%. 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.

Arctic Flash Freezing in November

 

After concerns over lackluster ice recovery in October, November is seeing ice roaring back.  The image above shows the last 10 days adding sea ice at an average rate of 215k km2 per day.  The Russian shelf seas on the right have filled with ice in this period.  On the CanAm side, Beaufort at the top left is iced over, Canadian Archipelago (center left) is frozen, and Baffin Bay is filling from the north down.  Hudson Bay (far left) has grown fast ice around the edges.  A background post is reprinted below, showing that in just 10 days, 2020 has added as much ice as an average 30-day November.

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.

Table 1 Monthly Arctic Ice rates of Extent Changes in M km2. Months with losses in pink, months with gains in blue.

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 2019.

As many know, there has been a decline of Arctic ice extent over these 40 years, averaging 40k 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 has been printed about October 2020 being slower than expected to refreeze and add ice extents. 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, October 2020 recorded a lower than average gain, but higher than 2016. The loss in July 2020 was the largest of the year, during the hot Siberian summer.  The bottom line presents the average anomalies for each month over the period 1979-2020.  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 30 years.

Note: SII daily extents file does not provide complete values prior to 1988.

Year-end Arctic ice extents (last 5 days of December) show three distinct regimes: 1989-1998, 1998-2010, 2010-2019. The average year-end extent 1989-2010 is 13.4M km2. In the last decade, 2009 was 13.0M km2, and ten years later, 2019 was 12.8M km2. So for all the the fluctuations, the net loss was 200k km2, or 1.5%. 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.

Arctic October Pent-up Ice Recovery

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.

Table 1 Monthly Arctic Ice rates of Extent Changes in M km2. Months with losses in pink, months with gains in blue.

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 2019.

As many know, there has been a decline of Arctic ice extent over these 40 years, averaging 40k 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 has been printed about October 2020 being slower than expected to refreeze and add ice extents. 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, October 2020 recorded a lower than average gain, but higher than 2016. The loss in July 2020 was the largest of the year, during the hot Siberian summer.  The bottom line presents the average anomalies for each month over the period 1979-2020.  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 30 years.

Note: SII daily extents file does not provide complete values prior to 1988.

Year-end Arctic ice extents (last 5 days of December) show three distinct regimes: 1989-1998, 1998-2010, 2010-2019. The average year-end extent 1989-2010 is 13.4M km2. In the last decade, 2009 was 13.0M km2, and ten years later, 2019 was 12.8M km2. So for all the the fluctuations, the net loss was 200k km2, or 1.5%. 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.