EGS Frank Week 8 Polar Environments Flashcards
1
Q
Overview P1/6
- (1) The polar environments are among the () places on earth but subject to () driven by ().
- (2) The () part of the Cryosphere consists of 1. (), 2. (), and its 3. (), 4. (), 5. (), 6. (), 7. () & 8. ().
- (3) These are not () distributed.
A
- (1) The polar environments are among the least inhabitated places on earth but subject to rapid changes driven by global greenhouse gas emissions.
- The frozen part of the Cryosphere consists of 1. snow, 2. Permafrost, and its 3. active layer, 4. sea ice, 5. ice caps, 6. glacial ice, 7. ice shelf & 8. iceberg.
- These are not equally distributed.
2
Q
Overview P2/6
- (4) The () accumulates the largest () annually, which is roughly () of the earth’s surface.
- (5) The () soils here are () & home to (), which also holds many (), especially ().
- (6) With current () trends, the () is () and releasing () into the ().
A
- (4) The Northern Arctic accumulates the largest aerial extent of snow annually, which is roughly 10% of the earth’s surface.
- (5) The Gelisol soils here are frozen & home to permafrost, which holds many frozen gases, especially methane.
- (6) With current warming trends, the soil is melting and releasing greenhouse gases into the atmosphere.
3
Q
Overview P3/6
- (7) () is also prevalent and subject to (), but also subject to () & () in the () months in the Arctic Ocean.
- (8) This leads to () Arctic Oceans & more ().
A
- (7) Sea ice is also prevalent and subject to strong seasonal cycles, but also subject to warmer summers & ever-decreasing ice cover in the summer months in the Artic Ocean.
- (8) This leads to warming Arctic Oceans & more melting.
4
Q
Overview P4/6
- (9) The Arctic is also home to (), which has a ().
- (10) () enters the () & increases the () of () to the oceans.
- (11) All of these factors contribute to ().
A
- (9) The Artic is also home to Greenland, which has a melting ice cap.
- (10) Meltwater enters the glaciers & increases the flowrates of glacial ice to the oceans.
- (11) All of these factors contribute to sea-level rise.
5
Q
Overview P5/6
- (12) Antartica is a (), the (), ~ () the size of Greenland, and the ().
- (13) It is much () than the Arctic & not subject to () or ().
- (14) Instead, (), which holds back the () & (), are () in () oceans.
A
- (12) Antartica is a continent, the largest ice cap, ~10 times the size of Greenland, and the largest store of global freshwater.
- (13) It is much colder than the Arctic & not subject to surface melting or home to much permafrost.
- (14) Instead, shelf ice, which holds back the glaciers & ice caps are breaking up in warming oceans.
6
Q
Overview P6/6
- (15) This leads to () and ().
- (16) Especially the () is home to breaking ().
- (17) All of these factors combined do () cause by () per year.
A
- (15) This leads to glacial acceleration and sea-level rise.
- (16) Especially the West Antartic Peninsula is home to breaking shelf ice.
- (17) All of these factors combined do currently cause sea-level rise by 3mm per year.
7
Q
What are the main components of the cryosphere?
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
8 points
A
- Snow
- Permafrost
- Active Layer
- Sea Ice
- Ice Cap
- Glacial Ice
- Ice Shelf
- Iceberg
8
Q
Polar Climate P1/2
- (1) Characterized by () due to factors like (), the (), (), & () from () & ().
- (2) These regions experience () & (), with () typically () annually, classifying them as ().
- (3) The () is largely () or in the form of (),
A
- (1) Characterized by Cold temps. due to factors like latitude, the Earth’s tilt, atmospheric paths, & high reflectance from snow & ice.
- (2) These regions experience polar high pressure & dry Arctic air, with rainfall typically less than 250mm annually, classifying them as deserts.
- (3) The available water is largely frozen or in the form of sea ice.
9
Q
Polar Climate P2/2
- (4) Though some () from currents like the ()/() and ()/().
- (5) Summers are () but feature (), with the warmest month potentially reaching up to ().
A
- (4) Though some polar maritime air from currents like the Japanese Current/Bering Current and Gulf Stream/Labrador Current.
- (5) Summers are brief but feature strong radiation, with the warmest month potentially reaching up to 10°C.
10
Q
Polar Soils P1/2
- (1) Polar soils, known as (), are characterized by (), which are found within () of the ().
- (2) These soils experience (), creating () that thaws & refreezes each year.
A
- (1) Polar Soils, known as Gelisols, are characterized by permanently frozen layers of Permafrost, which are found within 100cm of the soil surface.
- (2) These soils experience a seasonal melt, creating an active layer that thaws & refreezes each year.
11
Q
Polar Soils P2/2:
- (3) These soils cover ~ (), primarily in regions like (), (), () and ().
- (4) These soils often show signs of () and/or () in the (), which is the ().
A
- (3) These soils cover ~11 Ma km2, primarily in regions like USA (Alaska), Canada, Russia and Lesotho.
- (4) These soils often show signs of cryoturbation and/or ice segregation in the active layer, which is the seasonal thaw layer.
12
Q
Permafrost: A Carbon Source
- Permafrost is () deep
- Permafrost contains about ()
- Very () for a mineral soil
- Potential () also.
A
- Permafrost is 20-40m deep
- Permafrost contains about 500 Gt of C
- Very high carbon concentration for a mineral soil
- Potential methane gas release also
13
Q
Local Impact of Permaforst disturbance
- Disturbances, such as (), lead to () in the ().
- () results in (), (), () & ().
- These disturbances are often a result of (), (), but also ().
A
- Disturbances, such as the removal of insulation, lead to increases in the active layer.
- Permafrost melt results in Thermal Degradation, Subsidence, Melt Ponds & Thermokast formation.
- These disturbances are often a result of construction, fire, but also climate change.
14
Q
Sea Ice definition
A
Ice which forms @ the sea surface when water temp. falls below 0ºC
15
Q
Sea Ice P1/2
- (1) Sea Ice thickness is ().
- (2) The () thickness is () when () is () by ().
- (3) Its called () when floating freely with wind and currents.
- (4) () does not cause ().
- (5) But () changes ().
A
- (1) Sea Ice thickness is variable
- (2) The equilibrium thickness is 3m when surface melting is equalled by bottom freezing.
- (3) Its called Pack Ice when floating freely with wind & currents.
- (4) Melting does not cause sea-level rise
- (5) But Melting changes earth’s albedo.
16
Q
Sea Ice P2/2
- (6) Less () and () in Summer:→ Less ()→ More ()→ More ()→ () Ocean, Less () and ()→ () Feedback….. Not Good
A
- (6) Less Sea Ice and Snow in Summer:→ Less Reflectance→ More Heat Absorption By Water→ More Heating of Arctic Ocean→ Warmer Ocean, Less Ice and Snow→ Positive Feedback….. Not Good
17
Q
Ice Shelf Definition
A
Floating sheet of ice attached to the coast
18
Q
Ice Shelf
- Nourished by () and () from the ().
- Ice shelf may move by as much as () per year.
- () can be up to () tall.
- Shelf () is () and producing () when ice shelf is ().
- () of Antarctic coast is covered by ice shelves.
- The () Ice Shelf is () deep and () across.
- () → contact between () and ().
A
- Nourished by Snow fall and Glacial inputs from the land
- Ice shelf may move by as much as 1-3km per year.
- Seaward edge can be up to 60m tall.
- Shelf top is flat and producing tabular icebergs when ice shelf is calving
- 30% of Antartic coast is covered by ice shelves.
- The Ross Ice Shelf is 900km deep and 800km across.
- Grounding Line → contact between shelf and bottom
19
Q
Glacial Acceleration after Shelf Loss P1/6
The 4 Stages:
(1)
(2)
(3)
(4)
A
- Stable Glacier & Ice Shelf
- 2 Effects of Warmer Temps.
- Unstable Glacier Front After Ice Shelf Collapse
- Glacier Acceleration
20
Q
Glacial Acceleration after Shelf Loss P2/6
(1) Stable Glacier & Ice Shelf:
* Point:
* Point:
* Point:
A
- Glacier flow is driven by gravity (glacier moves downhill under own weight)
- Ice shelf is supported by a combination of buoyant (hydrostatic) forces @ ice shelf front, which helps keep the shelf in place, particularly @ the grounding line (where the ice meets the ocean floor).
- This buoyant force partially supports the ice shelf’s mass.
21
Q
Glacial Acceleration after Shelf Loss P3/6
(2) 2 Effects of Warmer Temps:
- Point 1:
(2) - Point 2:
(2)
A
-
Meltwater Infiltration:
1. As temp rises, meltwater forms on glacier surface & percolates down thru. glacier, speeding up the glacier’s flow.
- Typically occurs only in summer
-
Water-filled fractures:
1. Warmer temps can cause fractures in ice shelf which water fills, further weakening & destabilizing ice.
- Filled fractures carve thru. ice shelf -> shelf disintergration
22
Q
Glacial Acceleration after Shelf Loss P4/6
(3) Unstable Glacier Front After Ice Shelf Collapse:
- Point:
- Point:
- Point:
A
- Once ice shelf collapses & retreats past grounding line -> buoyant support that helped stabilize the ice shelf is lost.
- Even though support decreases, glacier flow continues, & glacier front starts to calve -> rapid loss of icebergs.
- Glacier becomes more unstable after this collapse
23
Q
Glacial Acceleration after Shelf Loss P5/6
(4) Glacier Acceleration:
- Point:
- Point:
- Point:
- Point:
A
- Ice shelf loss -> glacier acceleration
- Lower part of glacier steepens & speeds up -> increases ice flow to ocean.
- As glacier accelerates, begins to lose mass more quickly -> more rapid iceberg calving.
- Glacier’s surface also changes from its old, stable position to a new, steeper surface, which increases overall movement.
24
Q
Glacial Acceleration after Shelf Loss P6/6
Implications:
(1)
(2)
A
(1) Leads to a feedback loop
(2) This process contributes significantly to sea level rise as more ice flows into the ocean.
25
# Northern Vs Southern Polar Regions P1
* (1) Names
* (2) Hemisphere
* (3) Geography
* (4) Size
* (5) Snow
* (1) (N) **Arctic** & (S) **Antarctic**
* (2) Arctic (**Northern H**) & Antarctic (**Southern H**)
* (3) Arctic (an **Ocean** covered by a thin layer of perennial sea ice & surrounded by **land/continents**) VS Antarctic (a **Continent** covered by a very thick ice cap and surrounded by a rim of sea ice & an **Ocean**)
* (4) Arctic is slightly larger than the Antarctic
* (5) Both have significant snowfall but Arctic (snow on **sea ice** w. **more seasonal melting**) vs Antarctic (snow on **vast, stable ice sheet on land** w. **min. seasonal melting**).
26
# Northern vs Southern Polar Regions P2
* (6) Mountain Ice
* (7) Ice caps
* (6) Forms on high ground & ice caps for both BUT Arctic (**significant seasonal melting**) & Antarctic (**v. little melting**)
* (7)
Arctic:
**Greenland**:
→ **smaller** in size & volume than Antartica,
→ **surface water** in summer,
→ **lakes & rivers** present,
→ **more significant** negative mass balance
&
Antarctic:
**Antarctica**:
→ **larger** in size & volume than Arctic,
→ **no surface water** even in summer,
→ negative mass balance but **more warming in West Antartica** than East
27
# Northern vs Southern Polar Regions P3
* (8) Glaciers
Arctic:
→ Primarily **land-based** but has **sea-ice** too,
→ **smaller** & **less thick** than Antarctic's,
→ **more seasonal melting**,
→ **more prone to retreat**)
&
Antarctic:
→ Primarily **land-based** & part of **Antarctica Ice Sheet**,
→ **larger & thicker**,
→ **less prone to seasonal melting & retreat**
→ BUT **West Antarctica** & **Peninsula** show **increasing** melting/retreat.
28
# Northern vs Southern Polar Regions P4
* (9) Shelf Ice
* (10) Sea Ice
* (11) Permafrost
* (9) Very little shelf ice in Arctic vs Antarctica (Sudden break up noted in recent years since Larsen B as well as other areas)
* (10) Arctic:
→ **16 Ma km2 max. in Winter**,
→**summer min. dropping** &
→**melt seasons getting longer**
&
Antarctic:
→ (**20 Ma km2 max. in Winter**,
→ **slight increase in sea ice cover**
(11) Arctic:
→ **Most of world's** permafrost in the NH.
→ Active layer is natural but also disturbed by direct human impact.
&
Antarctic:
→ **Very little** permafrost in SH
29
# Northern vs Southern Polar Regions P5/5
* (12) Similarities
* Both **contributing to sea-level rise** thru. melting of land-based ice
* **Recent Ice Loss Acceleration**
* **Feedback Mechanisms** (albedo - Arctic & ice shelf collapse - Antarctic) that exacerbate ice loss.
30
# Why is Antartica so cold?
* Point 1
* Point 2
* Point 3
* Point 4
* Point 5
1. Antarctica is a **continent** surrounded by an ocean = **interior areas don't benefit** from the **moderating influence of water**
2. With 98% of its area covered with snow and ice, it **reflects most** of the **sun's light** rather than absorbing it.
3. The **extreme dryness of the air** causes **any heat** that is **radiated back** into the **atmosphere** to be **lost** instead of being absorbed by the water vapor in the atmosphere.
4. During the **winter**, the **size** of Antarctica **doubles** as the surrounding sea water freezes, effectively **blocking heat transfer** from the **warmer surrounding ocean**.
5. Has a **higher average elevation** than any other continent on Earth which results in even colder temperatures.
31
# What are the causes of sea-level rise?
(1)
(2)
(3)
(4)
(5)
(6)
(1) **Glaciers melting** & their increased movement & calving causes sea level rise
(2) **Mountain ice melting** (seasonal melting)
(3) **Ice Shelf Collapse** -> increase glacier movement -> ice flow to ocean -> SLR
(4) **Loss of Sea Ice** -> reduces surface albedo & causes ocean to become warmer -> indirect sea level rise
(5) **Permafrost melting** -> increase in greenhouse gas emissions -> warmer temps -> melting & sea level rise
(6) **Thermal Expansion** -> as ocean water warms -> expands -> SLR
