Weather and Climate Flashcards
Name the four major zones.
1) The Troposphere, where we live and where there is weather
2) The Stratosphere, where there is the ozone layer
3) The Mesosphere
4) The Thermosphere, where there is less than 0.1% of the atmosphere based on pressure
What is the most stable layer of the biosphere?
The Stratosphere
What is evidence of the Stratosphere’s stability?
The contrails of jets don’t dissipate quickly.
99.9% of the atmosphere is below…
50 km.
What percentage of the atmosphere is below 50 km?
99.9%
Where does temperature decrease with height?
The Troposphere
Where does temperature increase with height?
The Stratosphere
Zones where temperature decreases with height allows for ___ and ___ to occur.
Convection, mixing
Why is the temperate “warm” in the Stratosphere?
This is where stratospheric ozone resides. The absorption of shortwave, high energy ultraviolet light causes the temperature of this region to be elevated.
The temperature of the Thermosphere may be high, but why can’t I go there shirtless?
There is very little atmosphere with enough heat capacity.
What is responsible for the formation of clouds and rain?
The change in phase of water from gas to liquid and vice-versa
What are adiabatic processes? Give an example.
Physical processes that occur without the transfer of heat
Ex. If you press the nozzle of a compressed can of air, the can will feel cool to touch. Pressure is changing in the can, so the temperature decreases. This is an adiabatic process, because there was no heat exchange.
Tell me about La Niña.
Air rises near Australia so there is less atmosphere sitting on top of it, it expands and cools. When the temperature gets below the dew point, moisture is collected and a lot of rain occurs in Australia. This air moves to the Americas where it experiences high pressure, lowers, then flows across ocean surfaces, moving water in one direction and prompting deep ocean water to replace it (upwelling). This allows for fisheries to thrive.
Tell me about El Niño.
Precipitation occurs over the ocean and there is less upwelling. This allows for fisheries to collapse.
What are La Niña and El Niño?
These are weather patterns that occur over the Pacific Ocean.
What makes La Niña and El Niño possible?
Adiabatic heating and cooling
Why is it possible for air temperature to decrease with an increase in height even though hot air rises?
While hot air indeed rises, gas expands and cools as it does so. This happens when air is heated up by the ground, because it can’t be heated up directly by sunlight. The hot air headed by the ground rises, the volume of the gas increases and therefore its temperature decreases.
Why do clouds form with lifted air?
As a parcel of air is lifted up into the atmosphere, it is surrounded by less pressure, so the volume expands and the temperature decreases. When the air temperature drops below the dew point, condensation can occur and clouds can then form (so long there is the presence of cloud condensation nucleii – or VOCs!).
When the temperature of an air parcel is greater than that of the air surrounding it…
Unstable thermal stratification occurs.
When the temperature of the parcel is less than that of the air surrounding it…
Stable thermal stratification occurs.
Define orographic precipitation.
Air lifted by a mountain cools, condenses, forms clouds and prompts rain and snow. Rain and snow often allows for the windward side of the mountain to be green, while the leeward side stays dry.
Why are low pressure systems associated with soul weather?
In these systems, convergence happens: air rises, temperature decreases, vapor condenses, clouds form and rain is then possible. This is also made possible because air revolves around the pressure system in a counterclockwise manner.
High pressure is associated with ___. Hence, ___, ___ conditions form under high pressure systems.
Divergence (air sinks → temperature increases → cloud formation is suppressed). Hot, dry.
What leads to ascending air?
The clash of cold and warm fronts. Either a cold front pushes up against a warmer and more buoyant air or a warm front overrides the colder, denser air mass.
What are adiabatic processes responsible for?
Why lifted parcels of air may cool, condense, form clouds and rain.
Lifting of air is caused by four things. What are the four things?
- Fronts
- Convergence around low pressure
- Mountains (orography)
- Unstable thermal stratification (convection)
The sun emits ___ energy, mostly ___. The cooler earth emits ___ ___ radiation.
shortwave, visible, longwave, infrared
Describe the energy balance of the planet.
It starts with solar energy distributed across the hemisphere of the planet. Some of this energy is reflected by clouds or absorbed by atmospheric gas molecules. Some is transmitted through the atmosphere and reaches the surface where it is either absorbed or reflected. Energy absorbed by the air is emitted as longwave.
The amount of longwave energy emitted to space equals…
The amount of solar incoming minus solar reflected.
Warming does not affect the process of the sun’s shortwave energy and the earth’s longwave energy interacting. Rather, it affects ___.
How longwave energy is distributed throughout the atmosphere and how much reaches the surface
The surface is relatively warm compared to the effective sky temperature, because ___.
It receives longwave energy from the sky.
Why do we experience seasons?
The axis of the revolving Earth is tilted relative to the plane on which it revolves around the sun.
How many degrees is Earth’s axis tilted today?
23.5
Differential heating and rotations sets up cells of ___ and ___ air that become associated with the great forests and great deserts of the world.
ascending, descending
Warm air rises at the equator with ___ cells.
Hadley
Cool air descends at the poles with ___ cells.
Polar
Name the cells from the North Pole to the South Pole.
Polar, Ferrel, Hadley, Hadley, Ferrel, Polar
What are Rossby waves?
4-6 quasi-stationary waves that circumnavigate the planet. They have big impacts on the transport of cold air from the Arctic to temperate latitudes.
What is the significance of jet streams?
They steer our weather across the U.S. from west to east.
What would happen if a jet stream steered weather from east to west?
Big weather anomalies, including heat spells, droughts, cold spells and persistent wet periods that are independent of climate warming or cooling
What isotopic value of oxygen has been found to correlate well with temperature, and what is the significance of it?
- This means that temperatures can be reconstructed from ice cores.
Name three climate proxies.
- Paleontology
- Geochemistry
- Sedimentology
When we use paleontology to study the biosphere, what do we use?
Microfossils, forams, diatoms, and dinoflagilates
When we use geochemistry to study the biosphere, what do we use?
Stable isotopes and trace elements
When we use sedimentology to study the biosphere, what do we use?
Deep sea sediments, glacial sediments, ice cores, tree rings
Evaporation favors water with ___ isotopes, while condensation favors ___ isotopes.
Lighter (16O), heavier (18O)
When it is cold and ice is formed, this condensed water is trapped as snow and ice. What is the effect of this?
This causes ocean water to become progressively isotopically heavier and the future rain isotopically lighter.
List external climate forcing mechanisms.
- Solar radiation
- Earth orbital changes
- Asteroid impacts
List internal climate forcing mechanisms.
- Plate tectonics (mountains and weathering, ocean floor spreading, subduction)
- Volcanoes
- Ice sheets
- Ocean atmosphere feedbacks (like La Niña and El Niño)
Tell me about the Precambrian Era.
- Hot House and Ice Box
- Faint Sun Paradox: Earth was able to maintain a habitable environment (above freezing temperatures) for billions of years despite the solar constant being 30% lower than it is today.
- The Earth experienced numerous periods when the surface was frozen and covered in ice. These ages were overcome by CO2 and volcanism.
- CO2 and CH4 rich atmosphere
Tell me about the carbonate-silicate cycle.
- Volcanism injects CO2 into the atmosphere
- Feedbacks with rock weathering and the carbon cycle removes CO2
- Conversion to bicarbonate and transfer from land to sea puts carbon in large and long-lived reservoirs, forming limestone. Then tectonics take place: sea floor is subducted, limestone is metamorphised to CaSiO3 and CO2 is returned to the atmosphere via volcanism.
The rate of weathering ___ with temperature.
Increases
What is a product of weathering?
Bicarbonate
What is evidence of frozen Earth/ice ages?
Markers of glacial deposits, tilt of the Earth and its orbit around the sun, the ability of oceans to take up and release CO2, ocean circulations, ice albedo feedbacks and the impact melting glaciers’ weight has on volcanism
How did frozen Earth happen?
Rise in O2 → O2 reacts with methane → greenhouse warming is reduced
Tell me about the Phanerozoic Era.
- Life on Earth, plants and more advanced life, was most noticeable after this period.
- More advanced forms of life evolved over time across a wide range of climates. This promoted some life forms and caused the extinction of others and the system often restarted when favorable climate resumed.
Tell me about the Paleozoic Era.
- Land plants emerge, lowering planet albedo
- Land was supercontinent Pangaea with large ocean basin
- Volcanism elevated CO2 and warming, elevated temperatures
- Elevated O2 levels allowed for gigantism
- Glacial periods broke up Pangaea
Tell me about Cenozoic climates.
- Early period warmer than today
- Gradual cooling occurred over the most recent 50 million years. The uplift of the Himalayas caused weathering and uptake of CO2, causing Hot House warming
What do Milankovitch Cycles do?
They help explain the initiation and end of the glacial-interglacial periods over the past 800,000 years
Define eccentricity.
A parameter that determines the amount by which its orbit around another body deviates from a perfect circle
Define obliquity.
Axial tilt
Define precession.
The slow movement of the axis of a spinning body around another axis due to a torque (such as gravitational influence) acting to change the direction of the first axis
The greatest seasonality is based on what time scale?
The 100,000 year time scale
When does glaciation occur?
When insolation intensity is weak at high northern latitudes during the summer
What is the depth of the upper crust?
~100 km
What is different between Earth and Venus or Earth and Mars?
Earth has a liquid core; Mars and Venus do not.
What is the force that moves plates and continents?
Internal heat
What is evidence of continental drift?
Similarity of separated coast lines, similarity of fossils near coasts of widely separated continents, discovery of mid-ocean ridges and seafloor spreading
Pangaea broke up into two continents. What are their names?
Laurasia and Gondwanaland
How do plates move?
Convection cells. Heat associated with molten rock in the mantle causes convection, like movement by boiling water in a pot. Warm molten rock rises and cools as it does so. This movement allows for the formation of ridges and the spread of sea floor.
Trench formation is a product of…
Oceanic-continental convergence
Name the three types of rock.
Igneous, Sedimentary, Metamorphic
Name geomorphological processes.
Aeolian/wind, fluvial/floods, glacial/ice, gravitation, tectonic/earthquakes, igneous/volcanic, biological/weathering
