Exam II Flashcards
About what percent of Earth’s water can be found in the oceans?
70%
The amount of water vapor in the air (by volume) usually doesn’t exceed…?
4%
Relative humidity indicates the…?
Nearness to saturation.
Assume that the actual vapor content of the air remains constant over the course of the day. How does the relative humidity at 2pm probably compare to the RH at 5am?
The RH at 2pm is lower.
An instrument used to measure relative humidity?
Hygrometer.
The most common reason why dew forms on the grass at night?
Temperatures are coolest on the grass.
RH depends on the water vapor present in the air and…?
Temperature.
A radiation fog requires what in order to form?
High RH and clear nighttime skies.
The type of fog produced when cold air moves over a warm, moist surface?
Steam fog.
Which type of fog occurs during nights when skies are clear and RH is high?
Radiation fog.
When warm moist air moves over a cold surface, _____ fog may result?
Advection.
As the temperature of the air is reduced to its dew point, what’s most likely to occur?
Condensation.
An air parcel rises over a mountain and cools adiabatically. Which lifting mechanism has acted on this parcel?
Orographic lifting.
Which type of lifting mechanism results from warm air lifting over cold air?
Frontal wedging.
A stable atmosphere is one in which…?
Vertical motions are resisted.
Collision-coalescence is the predominant cause of precipitation in this region?
The Tropics.
Most of the precipitation that falls in the middle latitudes is formed by…?
The Bergeron Process.
The collision-coalescence process occurs when the entire cloud is?
Above freezing.
The raindrops that fall to Earth from a warm cloud contains about 1 million times the water in a typical cloud droplets. This growth from cloud droplets to raindrops occur mainly because of…?
The collision-coalescence process.
The largest form of precipitation is…?
Hail.
Sources of condensation nuclei?
Forest fires, wind erosion of soil and dust from industries and agriculture.
Rain droplets are initially what shape?
Spherical.
The process by which supercooled water droplets freeze onto falling ice crystals is called?
Riming.
Freezing rain…?
Requires a layer of cold air near the surface.
In the western part of N. America, snowfall distribution is primarily dependent upon what?
The presence of major north-south mt. ranges.
Coldest cloud type?
Cirrus.
A raindrop that freezes before reaching the ground is called?
Sleet.
Orographic uplifting is usually associated with the rising air…?
Along the windward side of mt.
Globally, annual precipitation amounts are highest in the…?
Tropical rain forests of S. America and Africa.
Lake effect snowfall requires…?
That the lake be relatively warm.
Lake effect precipitation?
Is caused by the wind blowing over an unfrozen lake surface.
Supercooled water is water which is…?
Still liquid at temperatures below 0 degrees C.
Hail is most commonly associated with?
Cumulonimbus clouds.
The wind belts between 30 and 60 degrees are the…?
Westerlies.
The doldrums refer to the same region as the?
Intertropical Convergence Zone.
The Hadley cell…?
Originates with strong solar heating at the equator.