APES Flashcards- The Atmosphere Flashcards

Terms Definitions
What compounds is earths atmosphere composed of?
Nitrogen (N2) 78%. Oxygen (O2) 21%, Water Vapor (H20)0-4%, Carbon Dioxide(CO2)<1, Methane (CH4)<1, Nitrous Oxide (N2O)<1, Ozone (O3)<1
atmosphere
the gaseous layer that surrounds the earth
when did the atmosphere form?
over four billion years ago
What are the layers of the atmosphere?
troposphere, stratosphere, mesosphere, and thermosphere.
troposphere
atmospheric layer closest to the earth's surface. It extends about 8 - 16 kilometers from the earth's surface. The thickness of the layer varies a few km according to latitude and the season of the year. It is thicker near the equator and during the summer, and thinner near the poles and during the winter. The troposphere contains the largest percentage of the mass of the atmosphere relative to the other layers. It also contains some 99 percent of the total water vapor of the atmosphere.weather occurs here. temp. decreases with latitude
tropopause
A narrow zone at the top of the troposphere effectively separates the underlying troposphere and the overlying stratosphere. The temperature in the tropopause is relatively constant. Strong eastward winds, known as the jet stream, also occur here.
jet stream
Strong eastward winds. occur in tropopause, extremely strong bands of winds that form in or near the tropopause due to large air pressure differentials. Wind speeds can reach as high as 200 kilometers per hour. In North America, there are two main jet streams: the polar jet stream, which occurs between the westerlies and the polar easterlies, and the subtropical jet stream, which occurs between the trade winds and the westerlies.
stratosphere
This layer extends from the tropopause (roughly 12 kilometers) to roughly 50 kilometers above the earth's surface. The temperature remains relatively constant up to roughly 25 kilometers and then gradually increases up to the upper boundary of the layer. The amount of water vapor in the stratosphere is very low, so it is not an important factor in the temperature regulation of the layer. Instead, it is ozone (O3) that causes the observed temperature inversion.This ozone layer absorbs solar energy in the form of ultraviolet radiation (UV), and the energy is ultimately dissipated as heat in the stratosphere. This heat leads to the rise in temperature.
Chapman Reactions
basic reactions involving only oxygen
production of ozone
absorption of high energy UV radiation (UVA) in the upper atmosphere.
destruction of ozone
by absorption of UV radiation involves moderate and low energy radiation (UVB and UVC
stratopause
upper boundary of the stratosphere, marked by a sudden decrease in temperature.
mesosphere
extends from the stratopause (about 50 kilometers) to roughly 85 kilometers above the earth's surface. Because the mesosphere has negligible amounts of water vapor and ozone for generating heat, the temperature drops across this layer.
thermosphere
extends outward from about 85 kilometers to about 600 kilometers.upper boundary is ill defined. The temperature in the thermosphere increases with altitude, up to 1500º C or more. The high temperatures are the result of absorption of intense solar radiation by the last remaining oxygen molecules. The temperature can vary substantially depending upon the level of solar activity.
ionosphere
lower region of the thermosphere (up to about 550 kilometers)important because it reflects radio waves from the earth's surface, allowing long-distance radio communication. The visual atmospheric phenomenon known as the northern lights also occurs in this region.
exosphere
outer region of the atmosphere, represents the final transition between the atmosphere and interplanetary space. It extends about 1000 kilometers and contains mainly helium and hydrogen. Most satellites operate in this region.
winds
Convecting air masses in the troposphere create air currents known as winds,Winds flow from a region of higher pressure to one of a lower pressure. Global air movement begins in the equatorial region because it receives more solar radiation.
Coriolis Effect.
The general flow of air from the equator to the poles and back is disrupted, though, by the rotation of the earth. The earth's surface travels faster beneath the atmosphere at the equator and slower at the poles. This causes air masses moving to the north to be deflected to the right, and air masses moving south to be deflected to the left.
convection cells
six, Belts of prevailing surface winds form and distribute air and moisture over the earth.
weather
refers to the short term changes in the physical characteristics of the troposphere. temperature, air pressure, humidity, precipitation, cloud cover, wind speed and directionadiant energy from the sun is the power source for weather. It drives the convective mixing in the troposphere which determines the atmospheric and surface weather conditions.
thunderstorm
forms in a region of atmospheric instability, often occurring at the boundary between cold and warm fronts. Warm, moist air rises rapidly (updraft) while cooler air flows down to the surface (downdraft).
Floods
occur when atmospheric conditions allow a storm to remain in a given area for a length of time, or when a severe thunderstorm dumps very large amounts of rainfall in a short time period. When the ground becomes saturated with water, he excess runoff flows into low-lying areas or rivers and causes flooding.
tornado
begins in a severe thunderstorm. Vertical wind shear causes the updraft in the storm to rotate and form a funnel. The rotational wind speeds increase and vertical stretching occurs due to angular momentum. As air is drawn into the funnel core, it cools rapidly and condenses to form a visible funnel cloud. The funnel cloud descends to the surface as more air is drawn in. Wind speeds in tornadoes can reach several hundred miles per hour. Tornadoes are most prevelant in the Great Plains region of the United States
cyclone
area of low pressure with winds blowing counter-clockwise (Northern Hemisphere) or clockwise (Southern Hemisphere) around it. Tropical cyclones are given different names depending on their wind speed. The strongest tropical cyclones in the Atlantic Ocean (wind speed exceeds 74 miles per hour) are called hurricanes.
hurricanes
trongest tropical cyclones in the Atlantic Ocean (wind speed exceeds 74 miles per hour)
upwelling
The less dense (lower salinity) warm water in the equatorial regions rises and moves towards the polar regions, while more dense (higher salinity) cold water in the polar regions sinks and moves towards the equatorial regions. Sometimes this cold deep water moves back to the surface along a coastline in a process known as............This cold deep water is rich in nutrients that support productive fishing grounds.
El Niño
prevents the nutrient-rich, cold-water upwellings along the western coast of South America. It also impacts the global weather conditions. Some regions receive heavier than usual rainfall, while other regions suffer drought conditions with lower than usual rainfall.
La Nina
occurs when tradewinds in the Pacific are unusually strong and equatorial oceanic surface temperatures are colder than normal
precipitation
rainfall or snowfall. Water from the vast salty oceans evaporates and falls over land as fresh water. It is rainfall that provides fresh water for land plants, and land animals. Winter snowfall in mountainous regions provides a stored supply of fresh water which melts and flows into streams during the spring and summer.
condensation nuclei
tiny (less than 1µm) dust or smoke particles, The condensation droplet is small enough (about 20 µm) that it is supported by the atmosphere against the pull of gravity. The visible result of these condensation droplets is a cloud.
Climate
a measure of a region's average weather over a period of time
Factors that influence climate
air mass, air pressure, albedo, angle of sunlight, clouds, distance to oceans, fronts, heat, land changes, latitude, location, moisture content of air, mountain ranges,, pollution, rotarion, wind patterns, human activity
Hadley air circulation cells
Air rises from equator: -rainforest-high humidity-high clouds; Sinks in subtropics: -low humidity-deserts
Ferrel air circulation cells
Develop between 30 an 60 N latitudes Subtropics, to midlatitude. polar air masses collide with tropical air masses
Polar air circulation cells
originate as icy cold dense air originates from the troposphere, meeting with warm tropical air from the troposphere. Low temps
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