earth science

Sea ice thickness

Sea ice thickness is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sea ice thickness rather than just read about it. In short: Sea ice thickness spatial extent, and open water within sea ice packs can vary rapidly in response to weather and climate. Sea ice concentration is measured by satellites, with the Special Sensor Microwave Imager / Sounder (SSMIS), and the European Space Agency's Cryosat-2 satellite to map the thickness and shape of the Earth's polar ice cover.

Key takeaways

Sea ice thickness belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sea ice thickness to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sea ice thickness from memory before moving on to harder problems.

Reference excerpt

Sea ice thickness spatial extent, and open water within sea ice packs can vary rapidly in response to weather and climate. Sea ice concentration is measured by satellites, with the Special Sensor Microwave Imager / Sounder (SSMIS), and the European Space Agency's Cryosat-2 satellite to map the thickness and shape of the Earth's polar ice cover. The sea ice volume is calculated with the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS), which blends satellite-observed data, such as sea ice concentrations into model calculations to estimate sea ice thickness and volume. Sea ice thickness determines a number of important fluxes such as heat flux between the air and ocean surface—see below—as well as salt and fresh water fluxes between the ocean since saline water ejects much of its salt content when frozen—see sea ice growth processes. It is also important for navigators on icebreakers since there is an upper limit to the thickness of ice any ship can sail through.

Measurement

Ice thickness can be measured in various ways, directly by taking an ice core and measuring it, remotely using point measurements from ice mass balance buoys, or more efficiently with satellite measurements. Measurements of ice depth below the waterline (or draft) by submarine sonar or radar systems can give good estimates of ice thickness provided there isn't too much snow (which is less dense than ice) on top. Sea ice freeboard is the difference between the height of the surface of sea ice and the water in open leads. Since 85–95% of snow-free sea ice is usually located below the waterline, the computation of the thickness is fairly simple; however, accurate measurement of ice freeboard is hindered by several factors including snow cover, and modeling of this data is being constantly improved.

Satellites The Ice, Cloud, and land Elevation Satellite (ICESat), measured ice sheet mass balance, cloud and aerosol heights, and land topography and vegetation characteristics, with an active service period from February 2003 to October 2009. The European Space Agency Soil Moisture and Ocean Salinity (SMOS) mission is the first orbital mission to measure salinity of the Earth’s surface and able to show data through most clouds and during darkness. The sea ice volume is calculated with the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS).

Other methods The E-M Bird ice thickness meter, designed by the Alfred Wegener Institute for Polar and Marine Research, is carried aloft by helicopter and measures ice thickness with a combination of a pair of inductance coils that measure the ice-water interface based inductance variations—similar to a metal detector—and a laser altimeter which measures the ice surface. It was used on a small scale in 2007 to supplement microwave radiometer measurements during the Pol-Ice campaign and on a much larger scale during the GreenICE (Greenland Arctic Shelf Ice and Climate Experiment) campaign conducted in 2004 and 2005.

See also Sea ice concentration Sea ice growth processes

References

Worked examples

Example 1 — a first encounter with Sea ice thickness

Start with the simplest possible case. Write down what Sea ice thickness claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sea ice thickness before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sea ice thickness ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sea ice thickness

In research: Sea ice thickness appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sea ice thickness in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sea ice thickness is common in secondary-school and first-year university syllabi. It links to neighbouring topics Climate, Climatology, Radiometry, so understanding it makes those chapters shorter.
In everyday life: Look for Sea ice thickness outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Sea ice thickness in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sea ice thickness means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sea ice thickness out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sea ice thickness in simple terms?

Why does Sea ice thickness matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sea ice thickness?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sea ice thickness.