Science Quiz Fronts and Weather 5/13 – Flashcards

High pressure, low pressure In general, worldwide movement of surface air from the poles toward the equator.

Temperature, pressure

Coriolis effect

Which occurs when winds are deflected by Earth's rotation. The processes that affect air movement also influence storms

A large body of air throughout which temperature and moisture are similar. Air masses that form over frozen polar regions are very cold and dry. Air masses that form over tropical oceans are warm and moist.

stationary If the air remains stationary or moves slowly over a uniform region, it takes on the characteristic temperature and humidity of that region.

source regions.

The source regions determine the temperature and the humidity of the air masses. The source regions for cold air masses are polar areas. The source regions for warm air masses are tropical areas.

Air masses that form over oceans. Maritime air masses are moist.The combination of tropical or polar air and continental or maritime air results in air masses that have distinct characteristics.

Continental tropical air masses form over the deserts of the southwestern United States. These air masses bring dry, hot weather in the summer. They do not form in the winter.

Air masses that form over land Continental air masses are dry. Continental air masses form over large landmasses, such as northern Canada, northern Asia, and the southwestern United States. Because these air masses form over land, the level of humidity is very low. An air mass may remain over its source region for days or weeks. However, the air mass will eventually move into other regions because of global wind patterns. In general, continental air masses bring dry weather conditions when they move into another region. There are two types of continental air masses: continental polar (cP) and continental tropical (cT). Continental polar air masses are cold and dry. Continental tropical air masses are warm and dry.

Polar air masses from three regions— northern Canada and the northern Pacific and Atlantic Oceans—influence weather in North America.

1. Atmospheric pressure 2. Humidity 3. Precipitation 4. Wind 5. Temperature

Measures air pressure, millibars or inches of mercury

Measures humidity Uses hair to measure humidity, hair expands and contracts in response to water vapor content in the air.

Measures humidity Difference between wet bulb and dry bulb used to determine relative humidity

Measures precipitation Simple funnel with marks associated with units: cm or in

Measures precipitation Counts the number of times the bucket fills and tips to determine rain fall or snow fall amounts

Measures temperature in °F and °C Made of two types of metal. Each metal contracts and expands at different temperatures

Measures temperature in °F and °C Usually uses alcohol. Some used mercury. Liquid contracts and expands in the glass tube.

Measures temperature in °F and °C The resistance in the electric current is measured

Measures temperature in °F and °C Measures the progression of temperature over a period of time.

Measures wind km per hour mi per hour

Wind Direction Cardinal units or numerical

Measures Upper-Atmospheric Conditions Carried aloft by a helium balloon Measures upper-atm. Conditions: relative humidity, air pressure, air temperature. Information sent back to scientists via radio...waves

Emits and receives "bounced back" radio waves from larger particles in the atmosphere

Enhanced version of standard radar. Detects subtle shifts of movement in all the particles in the atmosphere Can determine the size of particles allowing scientists to "see" the particles approaching

Carry cameras upper level cloud speed, direct hurricane observations infrared reading of cloud tops

Not as good as people but helpful! compiles information quickly create weather maps 100's of times faster than people

Cirrocumulus, cirrostratus, cirrus, anvil top for a cumulonimbus

Altocumulus, altostratus, cumulonimbus

Nimbostratus, stratus, stratocumulus, cumulus, cumulonimbus

density differences usually keep the air masses separate. A cool air mass is dense and does not mix with the less-dense air of a warm air mass. Thus, a boundary, called a front, forms between air masses.

For a front to form, one air mass must collide with another air mass. The kind of front that forms is determined by how the air masses move in relationship to each other.

Cold fronts A long line of heavy thunderstorms, called a squall line, may occur in the warm, moist air just ahead of a fast-moving cold front.

Warm front The less dense warm air rises over the cooler air. The slope of a warm front is gradual. Because of this gentle slope, clouds may extend far ahead of the surface location of the front.

Sometimes, when two air masses meet, the air moves parallel to the front and neither air mass is displaced. A front at which air masses move either very slowly or not at all.

Usually forms when a fast-moving cold front overtakes a warm front and lifts the warm air off the ground completely

are areas of low pressure that are characterized by rotating wind, which moves toward the rising air of the central, low-pressure region. These cyclones strongly influence weather patterns in the middle latitudes.

is a bend that forms in a cold front or a stationary front. This wave is similar to the waves that moving air produces when it passes over a body of water. However, the waves that form in a cold front or stationary front are much larger.

Over each of Earth's polar regions is a dome of cold air that may extend as far as 60° latitude. The boundary where this cold polar air meets the tropical air mass of the middle latitudes, especially over the ocean, is called the polar front. Waves commonly develop along the polar front.

However, the waves that form in a cold front or stationary front are much larger. They are the beginnings of low-pressure storm centers called midlatitude cyclones or wave cyclone.

the air in an anticyclone sinks and flows outward from a center of high pressure. Because of the Coriolis effect, the circulation of air around an anticyclone is clockwise in the Northern Hemisphere. If an anticyclone stagnates over a region for a few days, it may cause air pollution problems. After being stationary for a few weeks, an anticyclone may cause a drought.