GEOG220 Flashcards
How is pressure measured?
From above mean sea level
What direction does air circulate around low and high pressure systems?
Air flows clockwise around low pressure, anti-clockwise around high pressure.
Earth Circumference
40,000km
Earth Diameter
12,740km
Earth Surface Area
510 million km cubed, 70% ocean
Why does the difference between the Earth’s circumference and diameter matter in regards to rotation?
Because the earth rotates and completes a rotation every 24 hours, the equator has much further to travel than higher latitudes.
This creates a rotation speed gradient.
What forms the Coriolis Effect?
Objects at lower latitudes are moving at a greater velocity than objects at higher latitudes, due to the rotation speed gradient. Large-scale horizontal motion results in ‘apparent deflection’ of movement. This gradient creates the Coriolis effect, the deflection of horizontal movement.
Coriolis Effect
Deflection of horizontal movement. Causes air to circulate around high and low pressure systems, storm systems to spin, and different weather patterns and climate across latitudes.
Atmospheric Water (%)
0.001%
Why is atmospheric water important?
Responsible for energy transport (latent heat during phase transition), high heat storage, and is an extreme greenhouse gas - warming the earth.
What forms seasons?
The Earth is rotating on a tilted axis of 23.5* around the sun, meaning incoming solar radiation is targeted towards on hemisphere. When the rotation is perpendicular, neither hemisphere pointed towards or away, the Earth is in equinox to give spring/autumn. This gives us seasons.
True or False, distance from the sun influences seasons?
False, distance has no influence on seasonality.
What causes the tropics to be warmer?
The curvature of the Earth results in the uneven distribution of incoming radiation, with higher concentration at the equator. Tropics receive more direct radiation, giving warm tropics and cold poles.
Solar Zenith Angle
Angle of incoming radiation relative to the vertical. Near zero for direction radiation, near 90* for no radiation. This is why the tropics are warm and the poles are cold.
High Zenith Angle
= low net short-wave radiation = cooler climate
Energy
The ability or capacity to do work on matter.
Heat
Energy being transferred from one object to another because of temperature difference.
Celsius Scale
Based on freezing and boiling of pure water
Specific Heat
Heat energy needed to raise one gram of a substance one *C
Latent Heat
Heat energy required to change the state
Evaporation and Melt
Take in heat and cool surrounding environment
Condensation and freezing
Release heat and warm surrounding environment
Conduction
transfer of heat within a substance (solid).
Convection
transfer of heat by mass movement of a fluid (liquids and gases are able to move freely and form currents). Driven by differences in temperature.
Advection
horizontal transport of heat (warm ocean currents, cold southerlies). Driven by different processes of movement.
Thermal
rising bubble of air that carries heat energy upwards by convection (vertical movement).
Short-wave Radiation
UV, do not feel as heat, 50% absorbed by the earth and is reemitted as long-wave radiation.
Long-wave Radiation
feel as heat. It is reemitted by the earth, and absorbed by atmosphere and greenhouse gases.
Stefan-Boltzmann Law
The higher the temperature of the object emitting radiation:
- The greater the amount of radiation emitted
- The shorter the wavelength (higher the frequency) of the radiation emitted
Black body
perfect absorber and perfect emitter of radiation (incoming solar = outgoing terrestrial).
Hadley Cell - Thermally Direct (Temp Driven)
Circulation created by convection of heated surface air at the equator (ITCZ).
Air rising at equator turns poleward at the stable tropopause (deflected to the east forming westerly sub-tropic jets) –> air sinks/warms near 30*N/S (subtropical high pressure zones - creates deserts) –> surface winds return back to equator (surface trade winds converge at ITCZ).
Subtropic High Pressure Zone (30*N/S)
Thermally direct! Dominated by descending branch of the Hadley cell, producing warm and dry average climate conditions. Weak winds.
Ferrell Cell - Thermally Indirect
Fueled by the meeting and convergence of warm/cold air. Forms westerlies
Polar Cell - Thermally Direct (Temp Driven)
Warm air from tropics meets cold air from poles, different air mass properties create fronts and instability - storms.
Monsoon
land warmer than water
Continents heat (low pressure) and cool (high pressure) much faster than water, giving high pressure belt
Monsoon in NH Summer and Winter
Summer: Continents heat (low pressure) and cool (high pressure) much faster than water, giving high pressure belt. Westerlies move north. WET
Winter: Southward movement of ITCZ, farthest south over areas of continental heating. Westerlies move poleward. DRY
What controls ocean currents?
Wind. Gives rise to Gyres, Thermohaline.
What are the 4 climate types?
- Global
- Macro
- Meso
- Micro
Global Climate
the climate of entire planet
Macroclimate
climate of large area, size of state or country (1000km2)
Mesoclimate
small areas the size of few acres to hundreds kms (forests, valleys, cities, beaches)
Microclimate
very localised climate region (near ground vs metres above ground)
What are the 7 Climate Type Controls
I promise our wet pasta might accelerate.
- Intensity of insolation and variation
- Proximity of land/water
- Ocean currents
- Winds
- Position of high and low pressure systems
- Mountain barriers
- Altitude
Koppen-Geiger System
Classification of world climates based on annual/seasonal averages of temp and precipitation. Related to the distribution and type of vegetation.
Climate Zones - Koppen-Geiger System
(A) tropical moist climates
(B) dry climates (sub-tropical high pressure belt and rain shadows).
(C) moist mid-latitude climates with mild winters (western coasts of large continents and islands).
(D) moist mid-latitude climates with cold winters (interior regions of large continents)
(E) polar climates
Koppen-Geiger System: Moist Tropical Climate (A)
Within 20* latitude of equator. Warm and humid all year, with heavy precipitation.
Koppen-Geiger System: Dry Climate (B)
Cover 35% of Earth. North and South of humid tropical climates, within the descending Hadley Cell sub-tropical dry belt.
Divided into:
Hot (Bwh - BSh), annual temperature >18C
Cold (BWk - BSk), annual temperature <18C
Koppen-Geiger System: Temperate Mid-latitude Climate (C)
Middle latitudes of 40-60*.
Distinct summers and mild winters (never below 0*C).
Influenced by large bodies of water, with prevailing onshore winds.
Wet year-round with weather tied to fronts/mid-latitude storm track.
Koppen-Geiger System: Continental Mid-latitude Climate (D)
Very strong seasonal temperature variations, with hot humid summers and cold winters.
Located far from oceans relative to prevailing wind.
Precipitation year-round, but varies from convective thunder-storms in summer to snow in winter.
Koppen-Geiger System: Polar Climates (E)
Extremely cold winters and cold (short) summers, with warmest average temperature <10*C.
Little precipitation.
Differentiated by temperature alone.
Tundra (ET) - Warmest, 0-10C. Ice cap (EF) - <0C
Problems with Koppen-Geiger System
Too generalised (eg, NZ and topography)
Assumes sharp gradient between climatic zones (is gradual).
Synoptic Climatology
Relating surface climates to their regional atmospheric circulation patters.