Chapter 2 Flashcards
Climate
A scientist traveling on a boat from Alaska to Antarctica took daily atmospheric pressure measurements. At which latitudes were the lowest pressures found?
Subpolar (~60) and tropical (~0) latitudes
As air rises over a mountain, it….
cools and tends to lose moisture in the form of precipitation
In contrast with north-facing slopes, south-facing slopes in the Northern Hemisphere are characterized by… (and why?)
Greater soil moisture
Due to warm, wet air from tropics and ocean coming over south-facing slopes and losing moisture via precipitation. This keeps soil moist.
Seasonal variation in solar radiation, temperature, and day length is due to the…
tilt of Earth’s axis
Solar radiation in December is greatest at…
90degree latitude in the Southern Hemisphere
The transformation of water from a liquid state to a gaseous state is called
Evaporation
The two major atmopshere gases that absorb energy from the Sun are
Carbon Dioxide and Water Vapor
Where is temperature variation the greatest?
In the temperate regions
Why do beaches often have less extreme temperature variation than inland areas?
The ocean moderates the temperature
Without the greenhouse effect, the Earth would…
be much colder than it currently is.
Define weather
Occurs at a specific time/place and is the combination of any given atmospheric conditions
Define Climate
Long-term average pattern of weather. Shows patterns presented over decades
Define microclimate
Small regions in climates that may have slight variations from each other.
Define solar radiation
Also known as electromagnetic energy. Are the wavelengths the sun emits (from UV to visible to infrared)
What is the difference between short and long wavelengths?
Shorter wavelengths = higher energy
Longer wavelengths = lower energy / slower
Hotter object = shorter of a wavelength emitted
What can the energy emitted from Earth’s Surface do? (2 things)
- Go back into space (short wavelengths such as visible and UV typically)
- Be absorbed by atmospheric gases (longer waves typically)
What type of wavelengths do greenhouse gases absorb?
Long wavelengths such as thermal radiation (far infrared)
What are the main 3 greenhouse gases
Carbon Dioxide, Water Vapor, Methane
What happens when short wavelengths strike Earth?
Incoming shortwave radiation easily passes through the atmosphere and strikes the Earth. This transmits it’s energy and causes it to lose some of it’s energy -> longer wavelengths.
These longer wavelengths get “stuck” in the greenhouse gases (some does escape) and keeps our planets at a consistent climate temperature.
How can the atmosphere absorb infrared radiation? What does this radiation do to the molecules?
Due to the atmosphere containing electrically charged molecules (e-) and charged molecules (dipoles on water, etc.) which allows them to absorb energy from infrared radiation.
The absorption of infrared radiation causes thes molecules to move and bounce around.
~90% of infrared radiation can be absorbed
Why is there a decrease in the amount of solar (shortwave) radiation hitting Earth’s surface (when u move from the equator to the poles)
Because light travels straight. Essentially, light shoots out from any part of the sun in a straight line and hits the surface of the Earth unevenly. So at higher latitudes, solar radiation hits the surface at a steeper angle -> sunlight is spread over a larger area at the poles than at the equator.
Vernal/Autumnal Equinox
Occurs in Spring/Fall at approx. March and September. When solar radiation falls directly on the equator. Northern & Southern Hemisphere get the same amount o solar radiation.
Summer Solstice
Occurs in June. Solar radiation falls directly on Tropic of Cancer, causing increased input and day length in Northern Hemisphere.
Where is the Tropic of Cancer?
Northern Hemisphere
Winter Solstice
Occurs in December. Solar radiation falls onto Tropic of Capricorn, causing increased input and day length in Southern Hemisphere
Where is the Tropic of Capricorn?
Southern Hemisphere
Certain latitudes have deficits/surplus’ of incoming radiation, what does this cause?
Global patterns of heat redistribution from the equators to the poles due to these imbalances.
Mainly occurs through convection.
How does global heat redistribution from the equators to the poles occur?
Through convection.
Warm air at the equator rises, and flows North/South towards the poles. This air cools and descends to the surface, where it then flows to the equator.
What is the Intertropical Convergence Zone (ITCZ)
Zone near the equator where trade winds converge. This is also the zone in which warm air around the equator tends to rise
What causes the Coriolis Effect?
Earth spinning. Coroilis Effect is caused by the speed of rotation being faster at the equator and slower at the poles.
What does the Coriolis Effect do to winds in the Northern/Southern Hemisphere?
In Northern, wind deflects towards the East
In Southern, wind deflects toward the West
How do Compression/Deflection and Density affect air movement?
Density of air increases as the latitude increases, and compression/deflection is caused by convection.
Compression and deflection produces cells of air circulation
What latitudes have areas of low pressure? What happens to air in this area?
Equator - warm air rises. Causes the equatorial low. Results in warm air spreading north/south and cooling as it moves up latitudes.
60N and 60S - warm air rises. Warm air spreads north/south and cools as it moves up latitudes. Causes the Ferrel Cell and Westerlies Trade Winds.
What latitudes have areas of high pressure? What happens to air in this area?
30N and 30S - Cool air sinks in this area causing the high pressure. As the cool air sinks, it begins to warm up and spreads north/south close to the surface. Causes Hadley Cell and NE/SE Trade Winds
90N and 90S - Cool air sinks causing the high pressure. Results in the cool air warming as it descends spreading to the poles. Causes Polar Cell and Polar Easterlies
Name the global winds from 90N to 90S
Polar Easterlies -> Westerlies -> NE Trade Winds -> SE Trade Winds -> Westerlies -> Polar Easterlies
Name the air cells from 90N to 90S
Polar Cells -> Ferrel Cell -> Hadley Cell -> Equatorial Low (NO WIND) -> Hadley Cell -> Ferrel Cell -> Polar Cell
Define Currents
Patterns of water movement affected by global wind patterns and land
Define Gyres
Rotating global currents that are the main form of water movement in the oceans.
In Northern Hemisphere - clockwise
In Southern Hemisphere - counterclockwise
How do global winds affect currents?
Trade winds push warm surface water West. This water reaches continents and flows north/south and cools
Westerlies push colder water East. The water reaches the continents and flows towards the equator
Define Maritime Influence
Locations near the coast having small temperature fluctuations during the year and more precipitation
Define Continentality
Locations far from the coast having greater temperature fluctuations during the year (up to 100C in fluctuations)
Why does proximity to coastline influence climate?
Water’s high specific heat allows water to buffer temperature.
What happens as 2 warm air masses converge?
They begin to cool and rise, resulting in water vapor condensing and precipitation occuring.
What role does water vapor play in climate?
Water vapor has weight and exerts pressure.
Evaporation of water into water vapor requires energy to occur (so more solar radiation required)
Condensation of water vapor releases energy.
Saturation vapor pressure (VP) = water vapor capacity of air
What do shifts of the ITCZ cause?
Seasonality of precipitation (AKA rainy/dry seasons)
As distance from equator increases, dry season length increases.
What causes shifts in the ITCZ?
Changes in the Sun’s altitude between the equinoxes and solstices.
How do mountains affect local/regional climates?
As altitude increases, temperature decreases. At higher elevations have lower temps than lower elevations, even at the same latitude, resulting in different precipitation rate, plant life, and overall climates.
How do mountains affect precipitation?
Through its windward and leeward sides
What happens on the windward side of a mountain?
Air rises and cools as it goes up the windward side. It reaches the dew point and precipitation begins occurring at higher altitudes.
*More plant growth and trees at higher rainfall points
Once at the top of the mountain it is very cold and very dry (results in snowcaps!)
What happens on the leeward side of a mountain?
Cool, dry air flows down the leeward side and air begins to warm as it descends. This causes it to pull moisture from the surface resulting in a more arid/dry environment
Less rainfall = less plant growth and more shrubby plants.
What causes irregular variations in climate?
Changes in the shape of Earth’s orbit, changes in the tilt of Earth’s axis, variation in sunspot activity, magnetic storms on sun.
This affects the input/intensity of solar radiation
What is El Niño?
Also known as Southern Oscillation or ENSO, it is when waters in the Eastern Pacific Ocean begin to warm up.
What does El Niño cause? (6major things)
-Sea level pressure to drop
-Western pacific trade winds to weaken (due to rising of air masses decreasing)
-Upwellings in the Eastern Pacific are reduced (due to cold lower ocean layer no longer being pulled from bottom of ocean)
-Increased rainfall in Peru (due to warmer waters)
-Droughts in Australia/Indonesia (due to cooler waters in this area)
-Lower primary production in entirety of pacific ocean
What differences can microclimates have? How small could these microclimates be?
Differences in soil temp, moisture, wind movement, evaporation, vegetation
A microclimate can be as small as the difference between a patch of grass shaded by a tree VS a patch of grass not shaded by a tree within the same 10ft area.
