Weather
what you get (Short Term)
Climate
what you expect (Long Term) ; average over a period of time
Troposphere
lower-most atmospheric layer
o Temperature decreases by 6.4 degrees Celsius (average) per 1000 m in the troposphere
o Densest layer of the atmosphere (because gravitational pull weakens as we move father way from the Earth, molecules are more densely pack
Stratosphere
second most atmospheric layer
o Higher altitudes are warmer than lower altitudes because UV radiation reaches the higher altitudes first and warms them
o Ozone forms a layer within the stratosphere
Mesosphere
third most atmospheric layer
Thermosphere
fourth most atmospheric layer
o Blocks UV radiation and harmful X-rays
o Where auroras occur; it contains gas molecules that, when hit by solar energy, begin to glow and produce light, in the same way that a light bulb glows when electricity is applied.
Distances of layers of the atmosphere
Thermosphere - 480 km
Mesosphere - 80 km
Stratosphere - 50 km
Troposphere - 16 km
Explain why there is variation in the angle at which the Sun's rays strike the Earth
o The Sun's rays travel a shorter distance through the atmosphere to reach Earth's surface at the equator
o Therefore, more solar energy reaches the equator than the mid-latitude and polar regions because more solar energy is lost as it passes through the
Explain why there is variation in the amount of surface area over which the Sun's rays are distributed
o When sunlight strikes 90 degrees (equator) there is more solar energy over a smaller surface area there than at higher latitudes; thus tropical regions receive more solar energy per square meter than mid-Latitude and polar regions
o When it strikes at a
some areas of Earth reflect more solar energy than other; what is this called?
o Albedo = the percent of sun's light that is reflect
o Earth's average = 30%
o Asphalt = 5-10%
o Fresh snow = 80-95%
o Forest = 10-20%
o Water = 10-60% (depends on Sun's angle)
o Sea Ice = 50-90%
Mean Annual Net Radiation
Effects of incoming and albedo (outgoing)
- As you move outwards, more solar energy is being reflected (outgoing energy)
- High latitudes - energy deficit
- Poleward - heat transfer moves surplus energy from lower to higher latitudes
- Equator (warm air r
Water Vapor Capacity
o Warm air has higher capacity for water vapor than cold
o That's why hot summer days are associated with high humidity: the warm air contains a lot of water vapor
o Saturation point is the maximum amount of water vapor that can be in the air at a given t
Adiabatic heating
when air sinks towards Earth's surface, the pressure on it increases. The higher pressure forces the air to decrease in volume and this decreases the temperature of the air
Adiabatic cooling
as air rises higher in the atmosphere, the pressure on it decreases. The lower pressures allows the rising air to expand in volume, and this expansion lower the temperature of the air
Latent Heat Release
o When water vapor in atmosphere condenses into liquid water, energy is released
o Means that whenever water vapor in the atmosphere condenses, the air will become warmer, and this warm air will rise
Hadley cells
the convections currents that cycle between the equator and 30 degrees North and South
Intertropical convergence
the area of the earth that receives the most intense sunlight, where the ascending branches of the 2 Hadley cells converge
- Typified by dense clouds and intense thunderstorm activity
- Latitude where it's located is not fixes; moves north and south of th
Polar Cells
these convection currents are formed by air that rises at 60 degrees North and South and the poles (90 degrees North and South)
- At 60 degrees North and South, the rising air cools, and the water vapor condenses into precipitation
- The air dries as it m
Third area of air circulation
between the Hadley and the polar cells
- Air circulation is driven by the circulation of the Hadley and Polar cells
- Wind direction can be quite variable
What causes the Coriolis Effect and what is it?
Because all locations on Earth complete one revolution every 24 hours, and because Earth has a greater circumference near the equator than near the poles, its speed of rotation is much faster at the equator than near the poles
This causes the Coriolis Eff
The prevailing winds of the world are produced by
a combination of atmospheric convection currents and the Coriolis effect
o If the Earth did not rotate, the air within each convection cell would simply move directly north or south and cycle back again
Northeast trade wins
As air travels along Earth's surface toward the equator, Earth's speed increases, which causes the air movement toward the equator to be deflected to the west; this
causes the Hadley cell north of the equator to produce prevailing winds along Earth's surf
Southeast trade winds
As air travels along Earth's surface toward the equator, Earth's speed increases, which causes the air movement toward the equator to be deflected to the west which causes the air movement of the Hadley cell south
of the equator to produce prevailing wind
Westerlies
Closer to 30 degrees, air tends to move along Earth's surface away from the equator
since the Earth is rotating faster at 30 degrees than at 60 degrees, this air movement is deflected to the east
Combined effect of the air currents and the Coriolis effect
Prevailing Wind Directions in the polar regions
Air movement is deflected to the west because the polar cells move air away from the poles and toward 60 degrees latitude and the Earth is rotating faster at 60 degrees
- Because of this, polar winds come out of the northeast in the Northern Hemisphere an
Why do we have seasons?
the tilt of the Earth!
Earth's axis tilt = 23.5 degrees
Orbit is more circular not more....
elliptical; so seasons isn't about where you are in the orbit (i.e. - the farther you are from the sun, the less sunlight you get and that's winter) but if your hemisphere is titled toward or away from the sun
Explain the water and slope of the tropics
Tropics receive most sunlight and thus their waters are generally warm; this warm water, like warm air, expands and rises. This raises the tropical surface about 8 cm higher in elevation than mid-latitude waters; this slight slope is sufficient for the fo
Gyres
large-scale patterns of water circulation
o Each of the 5 major ocean basins contains a gyre driven by trade winds in the tropics and the westerlies in the mid-latitudes
o The result is a clockwise circulation pattern in the NH and a counter-clockwise cir
What do Gyres redistribute?
heat in the ocean
- cold water from the polar regions moves along the west coasts of continents and the transport of cool air from immediately above these waters causes cooler temperatures on land
- warm water from the tropics move along the east coasts o
Thermohaline Circulation
Another oceanic circulation that drives the mixing of surface water and deep water
Scientists believe this is crucial for moving heat and nutrients around the globe
Explain how thermohaline circulation works
- The sinking of dense, salty water in the North Atlantic drives a deep, cold current that moves slowly around the world
- Warm water flows from the Gulf of Mexico to the North Atlantic, where some of it freezes and evaporates
- The remaining water, now s
Heat Transport; what is it and give an example =
Ocean currents can affect the temperature of nearby land masses
For example, the ocean current known as the Gulf Stream originates in the tropics near the Gulf of Mexico and flows northeast across the Atlantic Ocean toward western Europe; as it transports
Concern about global warming with relation to thermohaline circulation
is that increased air temperatures could accelerate the melting of glaciers in the NH, which could make the waters of the North Atlantic less salty and less likely to sink; this could shut down the thermohaline circulation and stop the transport of warm w
Examples of Rain Shadows
Olympic Peninsula and Cascade Mountain Range in Washington State
Hawaii (the main island)
Name some comparable climates
Moscow and AA
China and DC
Phoenix and Cairo
Scotland and Seattle
Auroras
glowing, moving lights that are visible at high altitudes in both hemispheres are the product of solar radiation energizing the gases of the thermosphere
List the processes that affect weather and climate on a global scale
� Unequal heating of Earth by the Sun
� Atmospheric Convection Currents
� Rotation of the Earth
� Earth's orbit around the Sun on a tilted axis
� Ocean currents
Three primary causes of unequal heating of the earth by the sun
Variation in the angle at which the Sun's rays strike the Earth, Variation in the amount of surface area over which the Sun's rays are distributed, Some areas of Earth reflect more solar energy than other
Variations in Climate Determine
the Dominant Plant Growth forms of Terrestrial Biomes
Upwelling
Upward movement of water toward the surface
- Along the west coasts of most continents, for example, the surface currents diverge and cause the upwelling of deeper and more fertile water; this supports large populations of producers which support large po
Atmospheric convection currents
global patterns of air movement that are initiated by the unequal heating of the Earth
Formation of Convection Currents
1. At the ITCZ (intertropical convergence zone) the Sun heats the moist, humid air; this decreases its density and causes it to rise
2. The rising air experiences lower atmospheric pressures and adiabatic cooling, which causes water vapor to condense into
Air has 4 properties that determine its movement
density, water vapor capacity, adiabatic heating/cooling, latent heat release
Density of air
Density of air determines its movement
o Less dense air rises
o Denser air sinks
o At a constant atmospheric pressure, warm air has a lower density than cold air; therefore:
warm air rises and cold air sinks
Arctic oceans - get warmer when sea ice melts because of less reflection of solar energy, causing more ice to melt; is this a positive or negative thing?
positive thing
Ocean Currents are driven by a combination of
o temperature,
o gravity,
o prevailing winds,
o Coriolis effect,
o and location of the continent
Tundra
� Low annual temperature and low annual precipitation
� Treeless
� Frozen soil
� Short growing season
� Highest mountain ranges also
� Examples: Himalayas, Andes, Sierras, Greenland
� As earth warms, trees in Alaska will be able to grow in areas of Tundra
Permafrost
underlying subsoil that is an impermeable, permanently frozen layer that prevents water from draining and roots from penetrating; in Alaska, telephone poles tip because as it melts, they tilt; trees work the same way (drunken forests); put Styrofoam in gr
Patterned ground
collapsed ground
Pipelines in Alaska
above ground; radiators take heat from it and pass it upward so permafrost doesn't melt; goes in snake patterns and doesn't attach to cross bars because of expansion/contraction and earthquakes
Boreal Forest
Cold temperature, short season
� Mainly conifers
� Growth limited by temperature not by precipitation
� Just south of the tundra
� 2 seasons - July and Winter
Streams and rivers
characterized by flowing fresh water that may originate from underground springs as runoff from rain or melting snow; fast moving streams and rivers typically have stretches of turbulent water called rapids, where water and air are mixed together
Lakes and ponds
contain standing water; at least some of the standing water is too deep for emergent vegetation to grow
Freshwater wetlands
aquatic biomes that are submerged or saturated by water for at least part of each year, but shallow enough to support emergent vegetation through out; they support species of plants that are specialized to live in submerged or saturated soils
Salt marshes
found along the coast in temperate climes; they contain non-woody emergent vegetation; one of the most productive biomes in the world; many are found in estatuaries
Mangrove swamps
occur along tropical and subtropical coasts; contain trees whose roots are submerged in water and are salt tolerant; provide sheltered habitat for fish and shellfish
Intertidal zones
narrow band of coastline that exists between the levels of high tide and low rids
Coral reefs
found in warm, shallow water beyond the shoreline, represent Earth's most diverse marine biome; when a coral digest the food it captures, it releases CO2 and nutrients...the alge use the CO2 during photosynthesis to produce sugars; the nutrients stimulate
Open Ocean
the deeper water, where no sunlight can reach the ocean bottom; can be divided into several distinct zones
Aquatic Biomes are characterized by
salinity, depth, and water flow
Subtropical Dessert
� 30 degrees North and South with hot temperatures and extremely dry
� Cacti and succulent (water retaining) plants are well adapted
� High temperatures
� 0 precipitation
Tropical Seasonal Forest/Savanna
� Very warm and dry winters
� Some rain in summer
� Grasses and scattered deciduous trees
� Can be farmed due to fertile soils but precipitation is low
Tropical Rainforest
� Average annual temperature > 68 degrees F
� Greatest biodiversity
� Has about 2/3 of terrestrial species (why they must be preserved)
Temperate Grassland/Cold Dessert
� Lowest precipitation of any temperate biome
� Cold harsh winters
� Hot dry summers
� Plants constrained by cold in winter
� Lack of precipitation in summer
Woodland
� Hot dry summers
� Mild rainy winters
� "Mediterranean climate"
� 12 month growing season but summer is limited by precipitation
� Common in San Fran
� Wildfires are common
Temperate Seasonal Forest
� Lower precipitation
� Broadleaf deciduous trees
� Warm Summers
� Nutrient rich soils
Temperate Rainforest
� Coastal, mild, wet, long growing season, very large trees
� Moderate temperature and really wet, high productivity forest with moss and trees
� Cascades, South America, New Zealand, some in Australia
Atmosphere
gaseous envelope surrounding the Earth
o Made up of a series of connecting 'layers'
o Held down by gravity
o Most of its mass is near the surface (density of air decreases with altitude)
o Earth radius = 6400 km
Atmosphere = 99% below 30 km
(2 minutes fly
El Nino - Southern Oscillation
o Every 3-7 years, the interaction of the Earth's atmosphere and ocean cause surface currents in the tropical Pacific Ocean to reverse direction
During most years, trade winds push surface water from east to west; deep water moves upward (upwelling) to re
Example of a local feature that affects climate
rain shadows
Rain shadows
occur where humid winds blowing inland from the ocean meet a mountain range. On the windward (wind-facing) side of the mountains, air rises and cools, and large amounts of water vapor condense to form clouds and precipitation. On the leeward side of the m