Exam 1 Review Flashcards
What is the primary source of energy for the earth’s atmosphere?
The sun
What are the most abundant gases in the earth’s atmosphere by volume?
Nitrogen 78% and Oxygen 21%
Which gas is considered a variable gas in the earth’s atmosphere?
Water vapor
What is the only substance found naturally in the atmosphere as a solid, liquid, and gas?
Water
Which process removes carbon dioxide from the atmosphere?
Photosynthesis
What is the primary source of oxygen for the earth’s atmosphere during the past half billion years?
Photosynthetic organisms
What is the atmospheric layer in which we live called?
Troposphere
What is the rate at which temperature decreases with increasing altitude called?
Lapse rate
Which gas absorbs most of the harmful ultraviolet radiation in the stratosphere?
Ozone
At the 500 mb level, how does the amount of oxygen inhaled in a single breath compare to that inhaled at sea level?
Less than sea level
Which latitude would experience the fewest hours of daylight on Dec. 22?
The highest latitude (arctic/atlantic regions)
What is the highest latitude region?
Arctic/Atlantic regions
Why are northern latitudes not warmer than latitudes further south despite 24 hours of sunlight on June 22?
Summer solstice, sun directly above Tropic of Cancer
When does the maximum daytime surface temperature typically occur?
After the earth receives its most intense solar radiation.
What is the main reason summers in the Southern Hemisphere are not warmer than in the Northern Hemisphere?
More ocean coverage in the Southern Hemisphere moderates temperature.
Why is incoming solar radiation in middle latitudes less in winter than in summer?
The sun is lower in the sky and days are shorter.
What would happen if the earth’s tilt increased to 40°?
We would expect more extreme seasons in middle latitudes.
When does the greatest temperature difference between surface air and air several meters above occur?
On a calm, clear day.
Where does the greatest variation in daily temperature usually occur?
Over deserts and dry land areas.
When is the daily minimum temperature usually observed?
Just before sunrise.
How does the temperature of air next to the ground compare to the air above during the night?
Colder than the air above during the night.
How does the temperature of air next to the ground compare to the air above during the day?
Warmer than the air above during the day.
Why might ice crystals (frost) be observed on grass when the minimum temperature is reported as 35°F?
Ground-level temperatures are lower than air temperatures measured higher up.
When would a radiation temperature inversion best be developed?
Early morning, just before sunrise.
What does the lag in daily temperature refer to?
The time lag between peak solar radiation and peak temperature.
What are ideal conditions for a strong radiation inversion?
Clear skies, calm winds, and long nights
On a clear, calm night, how do the ground and air above cool?
Radiation cooling
What is an important reason for the large daily temperature range over deserts?
Low humidity and lack of clouds
Where would you expect to observe the smallest variation in temperature from day to day and from month to month?
Over oceans and near the equator
How does water heat up and cool off compared to land?
More slowly; more slowly
What provides a measure of the average speed of air molecules?
Temperature
What conclusion can be made if the temperature of the air is at absolute zero?
Molecular motion stops completely
What is released as sensible heat during the formation of clouds?
Latent heat of condensation
Which is the poorest conductor of heat?
Air
What is the amount of heat energy required to bring about a small change in temperature called?
Specific heat
How does rising air cool?
Expansion (adiabatic cooling)
At which temperature does the earth radiate energy at the greatest rate or intensity?
At the highest temperature
If the earth’s average surface temperature increases, what happens to the amount of radiation emitted?
Increase; shorter wavelengths
What happens if the amount of energy lost by the Earth to space each year is not approximately equal to that received?
The Earth’s climate would warm or cool.
What is the major process that warms the lower atmosphere?
Absorption and re-radiation of heat by greenhouse gases.
How does perspiration cool the body?
Evaporation.
What occurs if a glass of water is surrounded by saturated air?
No net evaporation or condensation.
When the air is saturated, which statement is NOT correct?
It can still hold more moisture.
How is the density of water vapor in a given parcel of air expressed?
Absolute humidity.
What will increase in a rising parcel of air?
Relative humidity.
What will decrease in a rising parcel of air?
Temperature.
What describes the ratio of the mass of water vapor in a given volume of air to the mass of the remaining dry air?
Mixing ratio.
What happens to the saturation vapor pressure when the air temperature increases?
It will increase.
What is the maximum pressure that water vapor molecules would exert if the air were saturated called?
Saturation vapor pressure.
If water vapor comprises 3.5 percent of an air parcel whose total pressure is 1000 mb, what would be the water vapor pressure?
35 mb.
What does a high water vapor pressure indicate?
High moisture content in the air.
What happens to actual vapor pressure if air temperature increases with no addition or removal of water vapor?
Remain the same
When the air temperature is below freezing, how does the saturation vapor pressure over water compare to that over ice?
Higher than the over ice
Why would a baseball travel farther in warm, humid air?
Lower air density in warm, humid air
Why are Gulf Coast states more humid in summer than Southern California coastal areas?
Warm gulf air vs. Cold pacific currents
What happens to the saturation vapor pressure and relative humidity when very cold air is warmed indoors with no change in moisture content?
Increase, decrease
In what type of climate are evaporative coolers primarily used?
Hot and dry
What will increase the relative humidity in a home during winter?
Using a humidifier or boiling water indoors
Which city has the highest relative humidity according to Exhibit 1?
City B
Which city has the least amount of water vapor in the air according to Exhibit 1?
City B
Which city has the greatest amount of water vapor in the air according to Exhibit 1?
City A
Which city has the highest saturation vapor pressure according to Exhibit 1?
City A
When is dew most likely to form?
on objects near the ground surface when they cool below the dew point temperature.
More likely on clear nights due to increased radiative cooling
What is the main cause of the cooling of the ground that produces dew?
Radiative cooling
What are particles that serve as surfaces for water vapor to condense on called?
Condensation nuclei
When does frost form?
When air reaches saturation below freezing
Why are condensation nuclei important in the atmosphere?
They provide surfaces for condensation
When does radiation fog form best?
Clear nights with shallow moist layer
If the minimum temperature drops to 34ºF on a clear night, what happens the following night if fog forms early?
The minimum temperature will not be as low because fog prevents further cooling
Where is radiation fog most likely to form on a cold winter morning?
Low lying areas (valleys, basins)
If fog is forming at Denver, Colorado, with wind blowing from the east, what type of fog is it most likely?
Upslope fog
What is the fog called that forms when warm rain falls into a cold layer of surface air?
Frontal fog
Which cloud is least likely to produce precipitation that reaches the ground?
Cirrus
What type of cloud is composed of ice crystals and can cause a halo around the sun or moon?
Cirrostratus
What cloud is most often associated with an anvil-shaped top?
Cumulonimbus
What type of cloud is hail usually associated with?
Cumulonimbus
What type of fog typically forms on clear calm nights?
Radiation fog
What causes upslope fog?
Moist Air cools as it flows up a hill or mountain range
What happens when two unsaturated air masses mix horizontally?
The resulting mixture cannot possibly be saturated.
What happens to air pressure inside a parcel if its temperature increases while its size remains the same?
The air pressure inside the parcel will increase.
What is the gas law?
Pressure = density x temperature x constant [PV=nRT]
Do pressure changes occur more vertically or horizontally?
More vertically.
What is constant on an isobaric surface?
Constant pressure.
What do the contour lines on a 500 mb chart represent?
Lines of constant height.
What type of air is normally found associated with high pressure on an upper-level chart?
Warm air.
What direction does the wind tend to blow on an upper-level chart?
Parallel to height contours.
What forces act to change the speed of the wind?
Pressure gradient force, Coriolis force, friction.
What is the amount of pressure change that occurs over a given horizontal distance called?
Pressure gradient.
What are the effects of the pressure gradient force?
Air moves from high to low pressure.
What is the Coriolis force a result of?
Earth’s rotation
What are the attributes of the Coriolis force?
Deflects winds to the right in the northern hemisphere, left in the southern hemisphere
Where do the winds aloft in the middle latitudes of the Southern Hemisphere generally blow?
West to east
What causes surface winds to blow across the isobars at an angle?
Friction
How does the wind blow around a surface high pressure center in the Northern Hemisphere?
Clockwise
What are the assumptions of the single-cell model of the general circulation of the atmosphere?
No rotation, no friction, single basic cell from equator to poles
What is the large thermally driven convection cell that is driven by convective ‘hot’ towers along the equator?
Hadley cell
What is the intertropical convergence zone (ITCZ)?
A region where trade winds converge
Where should areas of surface low pressure be found in the three-cell model of general circulation?
Near the equator and 60° latitude
Which wind belt does the majority of the United States lie within?
Westerlies
Where would the trade winds be observed on a weather map of the Northern Hemisphere?
Between 0 and 30° latitude
Where should the driest regions of the earth be found in terms of the three-cell general circulation model?
Near subtropical high pressure zones, around 30° latitude
How does the position of the Pacific high over the North Pacific Ocean shift in summer and winter?
Shifts south in summer and north in winter
In the Northern Hemisphere, when is the polar jet stream strongest?
In winter, when temperature gradients are greatest.
How does the jet stream flow?
West to east in both hemispheres.
What does the Ekman Spiral describe?
Wind driven ocean currents with depth.
What is upwelling?
Cold water rises to replace warm surface water.
What happens during a major El Niño event?
Warm water spreads eastward, affecting global weather.
What is the condition called when the central and eastern tropical Pacific Ocean turns cooler than normal?
La Niña.
What is the reversal of the positions of surface high and low pressure at opposite ends of the Pacific Ocean called?
Southern Oscillation.
