On Thermal Expansion & Thermal Contraction - 48

Ocean Areas

I. Forward

The previous post in this series featured latitude "layers" (a horizontal look at variations in ocean water characteristics along latitude bands). 

In today's post, the graphs of TEOS-10 concepts Conservative Temperature, Absolute Salinity, and Thermal Expansion and Contraction are provided for several Ocean areas on an ocean by ocean basis.

Those graphs are contained in three appendices (Arctic/Atlantic; Indian / Southern; and Pacific).

The thirty-three (33) depth 'levels' of each graph reach from the surface to the bottom, but they are separated into three different colors.

Each color-section contains  11 rows of lines, each line representing a particular depth. 

There is an "About" section at the top of each appendix page, pointing out more specifics about the depths.

II. Different Zones

The WOD Zones in the layered approach in the previous post of this series are not the same as those in this per-ocean approach (On Thermal Expansion & Thermal Contraction - 47).

Thus, the lines will not be the same.

They are mean averages of the zones of one ocean area, whereas the layered approach contains zones from different oceans at some locations.

The Southern ocean data will not be the same as the lines in layers 14 and 15 in the previous post's layered approach

III. Same Results

The resulting principles are the same however, which is that thermosteric sea level change is not the major cause of sea level rise, nor is it even a major cause.

The previous post has links to more details about thermal expansion and contraction.

But the basic exercise is to calculate the mass/volume of a depth level, each one of the 33 individual slices of the total WOD Zone, then calculate the expansion and contraction of that slice (length x width x height = volume).

Then apply the temperature changes and thermal expansion coefficient to each volume slice.

Repeat often because change is real (Sea Ice Today).

The next post in this series is here, the previous post in this series is here.

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Indian and Southern

This is an appendix to: On Thermal Expansion & Thermal Contraction - 48

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ABOUT:

depth level volume = length x width x height (h)

I. Red Lines

The 11 red lines (0m to 300m; h=300) on the graphs depict sea water charisteristics at the following depths:

"0m down to 10m",
"11m down to 20m",
"21m down to 30m",
"31m down to 50m",
"51m down to 75m",
"76m down to 100m",
"101m down to 125m",
"126m down to 150m",
"151m down to 200m",
"201m down to 250m",
"251m down to 300m"

II. Blue Lines

The 11 blue lines (400m to 1400m; h=1100) on the graphs depict sea water charisteristics at the following depths:

"301m down to 400m",
"401m down to 500m",
"501m down to 600m",
"601m down to 700m",
"701m down to 800m",
"801m down to 900m",
"901m down to 1000m",
"1001m down to 1100m",
"1101m down to 1200m",
"1201m down to 1300m",
"1301m down to 1400m"

III. Cyan Lines

The 11 cyan lines (1500 to 5500m; h=4000+) on the graphs depict sea water charisteristics at the following depth levels:

"1401m down to 1500m",
"1501m down to 1750m",
"1751m down to 2000m",
"2001m down to 2500m",
"2501m down to 3000m",
"3001m down to 3500m",
"3501m down to 4000m",
"4001m down to 4500m",
"4501m down to 5000m",
"5001m down to 5500m",
"5501m down to the bottom"

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Sea Ice Today

This is an appendix to: On Thermal Expansion & Thermal Contraction - 48

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Antarctic sea ice extent sets a new record low

February 14, 2023

Antarctic sea ice extent appears to have broken the record low set last year. With a couple more weeks likely left in the melt season, the extent is expected to drop further before reaching its annual minimum. Much of the Antarctic coast is ice free, exposing the ice shelves that fringe the ice sheet to wave action and warmer conditions.

Overview of conditions

Figure 1a. This map of Antarctica shows many low areas of sea ice concentration, depicted as darker blues, surrounding the continent, rendering extent likely to decrease in the coming days or weeks. Antarctic sea ice extent for February 13, 2023, was 1.91 million square kilometers (737,000 square miles). The orange line shows the 1981 to 2010 median extent for that day. Sea Ice Index data. About the data

Credit: National Snow and Ice Data Center
High-resolution image

Figure 1b. The graph above shows Antarctic sea ice extent as of February 13, 2023, along with daily ice extent data for four previous years and the record high year. 2022 to 2023 is shown in blue, 2021 to 2022 in green, 2020 to 2021 in orange, 2019 to 2020 in brown, 2018 to 2019 in magenta,and 2013 to 2014 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data.

Credit: National Snow and Ice Data Center
High-resolution image

On February 13, 2023, Antarctic sea ice extent fell to 1.91 million square kilometers (737,000 square miles) (Figure 1a). This set a new record low, dropping below the previous record of 1.92 million square kilometers (741,000 square miles) set on February 25, 2022 (Figure 1b). This year represents only the second year that Antarctic extent has fallen below 2 million square kilometers (772,000 square miles). In past years, the annual minimum has occurred between February 18 and March 3, so further decline is expected.

Conditions in context

Figure 2. This graph shows Antarctic annual sea ice minimum extent, depicted as black diamonds, from 1979 to 2023, based on a 5-day running average
of daily extent. The grey diamond data point depicts the 2023 minimum, which is still preliminary, with further loss expected. The linear trend line is in blue with a 0.9 percent per decade downward trend, which is not statistically significant. A five-year running average is shown in red. As the Antarctic melt season is still in progress, depicted as a grey downward arrow, the linear trend and running average will change slightly.

Credit: W. Meier, NSIDC
High-resolution image

Extent has tracked well below last year’s melt season levels since mid-December. As noted in our previous post, a positive Southern Annular Mode has led to stronger-than-average westerly winds. Along with a strong Amundsen Sea Low, the weather conditions have brought warm air to the region on both sides of the Antarctic Peninsula. This has largely cleared out the ice cover in the Amundsen and Bellingshausen Seas, and reduced the sea ice extent in the northwestern Weddell Sea. Sea ice is patchy and nearly absent over a long stretch of the Pacific-facing coastline of Antarctica.  Earlier studies have linked low sea ice cover with wave-induced stresses on the floating ice shelves that hem the continent, leading to break up of weaker areas.

Antarctic sea ice extent has been highly variable over the last several years. While 2022 and 2023 have had record low minimum extent, four out of the five highest minimums have occurred since 2008. Overall, the trend in Antarctic minimum extent over 1979 to 2023 is near zero. The current downward linear trend in the Antarctic minimum extent from 1979 to 2023 is 2,400 square kilometers (930 square miles) per year, or 0.9 percent per decade, which is currently not statistically significant. Nevertheless, the sharp decline in sea ice extent since 2016 has fueled research on potential causes and whether sea ice loss in the Southern Hemisphere is developing a significant downward trend.

Greenland and Antarctic Ice Sheet Today

Sea Ice Data and Analysis Tools

Arctic and Atlantic

This is an appendix to: On Thermal Expansion & Thermal Contraction - 48

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ABOUT:

depth level volume = length x width x height (h)

I. Red Lines

The 11 red lines (0m to 300m; h=300) on the graphs depict sea water charisteristics at the following depths:

"0m down to 10m",
"11m down to 20m",
"21m down to 30m",
"31m down to 50m",
"51m down to 75m",
"76m down to 100m",
"101m down to 125m",
"126m down to 150m",
"151m down to 200m",
"201m down to 250m",
"251m down to 300m"

II. Blue Lines

The 11 blue lines (400m to 1400m; h=1100) on the graphs depict sea water charisteristics at the following depths:

"301m down to 400m",
"401m down to 500m",
"501m down to 600m",
"601m down to 700m",
"701m down to 800m",
"801m down to 900m",
"901m down to 1000m",
"1001m down to 1100m",
"1101m down to 1200m",
"1201m down to 1300m",
"1301m down to 1400m"

III. Cyan Lines

The 11 cyan lines (1500 to 5500m; h=4000+) on the graphs depict sea water charisteristics at the following depth levels:

"1401m down to 1500m",
"1501m down to 1750m",
"1751m down to 2000m",
"2001m down to 2500m",
"2501m down to 3000m",
"3001m down to 3500m",
"3501m down to 4000m",
"4001m down to 4500m",
"4501m down to 5000m",
"5001m down to 5500m",
"5501m down to the bottom"

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Pacific

This is an appendix to: On Thermal Expansion & Thermal Contraction - 48

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ABOUT:

depth level volume = length x width x height (h)

I. Red Lines

The 11 red lines (0m to 300m; h=300) on the graphs depict sea water charisteristics at the following depths:

"0m down to 10m",
"11m down to 20m",
"21m down to 30m",
"31m down to 50m",
"51m down to 75m",
"76m down to 100m",
"101m down to 125m",
"126m down to 150m",
"151m down to 200m",
"201m down to 250m",
"251m down to 300m"

II. Blue Lines

The 11 blue lines (400m to 1400m; h=1100) on the graphs depict sea water charisteristics at the following depths:

"301m down to 400m",
"401m down to 500m",
"501m down to 600m",
"601m down to 700m",
"701m down to 800m",
"801m down to 900m",
"901m down to 1000m",
"1001m down to 1100m",
"1101m down to 1200m",
"1201m down to 1300m",
"1301m down to 1400m"

III. Cyan Lines

The 11 cyan lines (1500 to 5500m; h=4000+) on the graphs depict sea water charisteristics at the following depth levels:

"1401m down to 1500m",
"1501m down to 1750m",
"1751m down to 2000m",
"2001m down to 2500m",
"2501m down to 3000m",
"3001m down to 3500m",
"3501m down to 4000m",
"4001m down to 4500m",
"4501m down to 5000m",
"5001m down to 5500m",
"5501m down to the bottom"

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