Topic 10: Earth's Atmosphere and Terrestial Water Flashcards
Describe the Earth’s energy budget and the mechanism utilized to achieve balance
At the equator we are gaining more energy than we emit, at the poles we are losing more than we are gaining.
Movement of the atmosphere and oceans redistribute this heat energy to adjust such natural imbalance.
Identify and describe the temperature and pressure gradient in layers of the atmosphere
4 layers: troposphere, stratosphere, mesosphere, thermosphere
- Temperature:
+ Earth’s surface absorbs heat –> heat up the air above it –> air hotter, expands, less dense, further particles –> unable to retain heat –> decreasing as going up in the troposphere
+ Increases again in the stratosphere (where ozone layer absorbs UV radiation)
+ Particles spread out again –> decreases in the mesosphere
+ Particles very spread out in the thermosphere but they interact strongly with the energy from the Sun to the Earth –> increasing temperature - Pressure: decreasing as going up
+ air molecules below are compressed by those above
+ related to density (increasing density means the particles are more densely packed)
Explain why trace gases are profoundly important for the habitability of our planet
Greenhouse gases help to trap and reflect some radition from the Sun, help creating a nice, warm, balmy atmosphere.
Greenhouse effect: short-wave light goes through the layers of greenhouse gasses because these gases cannot absorb short-wave light
+ some is reflected but most is absorbed by the Earth. converted to long-wave and infrared radition
+ this can be reaborbed by greenhouse gases or reemitted –> warming of the earth’s surface and troposphere –> warm, balmy atmosphere
+ natural process, but amplified by increase in GHG
What is the Keeling Curve?
Daily record of global atmospheric carbon dioxide concentrations initiated at Mauna Loa since 1958.
What is Coriolis force?
This is a force acting on objects that are in motion (like wind and water) relative to a rotaing reference frame (the Earth in this case), causing them to deflected.
Explain how air moves in general
As air gets hotter at the surface at the equator (most energy), it rises and pushes all the air molecules up, ending up with low pressure below and high pressure above.
Up there, air expands, then cools down, so pressure starts to go down as air travels at higher latitude.
Cool air then sinks, pushes the air molecules down, resulting in high pressure at the surface.
High pressurized air then flow back to the equator where air pressure is lower.
Identify and describe the three cell global circulation model and how it affects the climate at different latitude
- Hadley cell: between equator and 30 degree latitude
+ Air rises at the equator –> low pressure at the surface, higher above –> wet climate, rain forests
+ Air sinks at the 30 degree latitude –> high pressure at the surface, lower above –> dry climate, deserts
==> thermoly directed - Polar cell: between 60 degree latitude and pole
+ Air rises at 60 degree latitude –> lower pressure at the surface, higher above –> wet climate
+ Air sinks at pole –> higher pressure at the surface, lower above –> dry climate
==> thermoly directed - Ferrel cell: affected by 2 other cells
+ Air sinks at 30 degree latitude –> higher pressure at the surface, lower above
+ Air rises at 60 degree latitude –> lower pressure at the surface, higher above
What is salinity and how is it altered in the oceans?
Salinity is a measure of the sea saltiness. Mostly Na+ and Cl- ions (NaCl - table salt)
- Adding salt:
+ chemical weathering (break down rocks and minerals –> detrital materials on coastline and dissolved components –> runoff to oceans and add salts)
+ from dusts. volcanic explosion
+ underwater volcanoes - Removing water:
+ evaporation
+ solidification of ice (capture ions) - Removing salt:
+ sulphate reduction
+ formation of carbonate –> remove ions
+ absorbed into minerals
+ biological processes - Adding water:
+ precipitation
+ ice melting
+ runoff from land
What are halocline and thermocline and how are they related to the vertical stratification of Earth’s ocean?
- Halocline: zone of large salinity change
- Thermocline: zone of large temperature change
- As going down, salinity increases –> saline water is more dense than fresh water
- As going down, temperature decreases –> cold water is more dense than hot water
What is deeper water circulation driven by?
Deeper water circulation is driven by differences in water density, which is controlled by differences in salinity and temperature.
What are some factors that could slow down the water current and reduce/prevent deep ocean water production?
- Increasing temprature
- More glaciers melting –> more fresh water, preventing slinity factor to drive circulation
Identify and describe factors affecting deep and surface ocean currents
- Deep ocean currents: driven by density which are affected by differences in salinity and temperature
- Surface ocean currents: wind patterns and coriolis force
+ As wind moves along the surface, it drags water
+ Ekman spiral: coriolis force –> water currents deflect as going down –> spiral with decreasing intensity(realistic)
+ Ekman transport: in general, the net water transport can be describes as perpendicular to the direction of wind
+ In the Northern hemisphere, Ekman transport direction is away from coastline –> water moving away from coastline, sinking and moving upwards again at coastline –> surface water at coastline: cold, salty, nutrient rich
+ In the Southern hemisphere, Ekman transport direction is towards the coastline –> water moving towards the coastline, sinking, and moving upwards in the ocean –> surface water at coastline: warm, fresh, nutrient poor
+ gyres: clockwise in Northern, counterclockwise in Southern
How does ocean acidification occur?
As more CO2 is absorbed by the ocean, the equation is moving towards producing more H+ and CO3(2-). More hydrogen ions means lower pH.
The system will try to restore equilibrium by pushing backwards to take more CO3(2-) to react with H+ and make more HCO3- –> increase in H+ and less CO3(2-) available for organisms to build skeletons or protective layers, especially ones that are important in photosynthesis process.
How does Coriolis force drive the direction of wind and water in the two hemispheres?
- Northern Hemisphere: to the right –> clockwise
- Souther Hemisphere: to the left –> counterclockwise
Why are oceans important?
- Global water cycle - evaporation and transpiration
- Store and transport heat
- Life and biodiversity
- Oxygenate atmosphere and recycle nutrients
- Carbon sink
