Meteorology Flashcards

Flashcards covering elements of weather, atmospheric pressure, humidity, and cloud formation.

Weather

Condition of the atmosphere over a certain place within a short period of time, constantly changing with continuous and erratic changes.

Weather Elements

Air temperature, atmospheric pressure, humidity, type of clouds, amount of rainfall, wind speed and direction; a change in any of these can directly change the other.

Atmospheric Pressure

Commonly known as air pressure, defined as the pressure exerted by the weight of air above; force exerted against a surface by continuous collision of gas molecules.

Evangelista Torricelli

An Italian scientist who invented the first mercurial barometer to measure atmospheric pressure.

Mercury Barometer

When atmospheric pressure is higher, the mercury column is pushed taller; when atmospheric pressure is lower, the height of the column of mercury drops.

Aneroid Barometer

A portable device that can measure atmospheric pressure; contains a metal device that is sensitive to pressure difference.

Atmospheric pressure variation with altitude

The higher the elevation above the surface, the lower the pressure, and One half of the atmosphere lies below an altitude of 5.5 km.

Latent Heat

Also known as hidden heat, it's the heat involved during phase changes where addition or removal of this heat on the substance does not involve a change in temperature reading.

Evaporation

The process of converting a liquid into a gas (vapor). Energy is supplied to allow liquid molecules to escape from the surface of the liquid; a cooling process.

Condensation

Occurs when water vapor changes to liquid state; an energy-releasing process important in the formation of fogs and clouds.

Humidity

Moisture of the air; the general term for the amount of water vapor in air. Meteorologists agree that water vapor is the most important gas in the atmosphere when it comes to understanding atmospheric processes.

Vapor Pressure

The part of the total atmospheric pressure that can be attributed to water vapor content.

Mixing Ratio

The mass of water vapor in a unit of air compared to the remaining mass of dry air. Not affected by changes in temperature and pressure but is time-consuming to measure.

Relative Humidity (RH)

The ratio of the air’s actual water vapor content compared with the amount of water vapor required for saturation at that temperature and pressure.

Dew Point Temperature

The temperature to which a parcel of air would need to be cooled to reach saturation; a measure of actual moisture content.

Hygrometer

An instrument commonly used to measure relative humidity. One type of hygrometer is the psychrometer, which consists of two identical thermometers mounted side by side.

Adiabatic Cooling

When air is allowed to expand, it cools; when it is compressed, it warms. Meteorologists call this parcel of air.

Dry Adiabatic Rate

Unsaturated air cools at a constant rate of 10°C for every 1000 m of ascent.

Wet Adiabatic Rate

The slower rate of cooling caused by the addition of latent heat, approximately 5°C to 9°C per 1000 m of ascent.

Orographic Lifting

Air is forced over a mountainous barrier, and as air ascends over a mountain slope, adiabatic cooling often generates clouds and copious precipitation.

Frontal Wedging

Warmer, less dense air is forced over cooler, denser air due to the collision of warm and cold air masses.

Convergence

A pileup of horizontal air flow results in upward movement; a mechanism of forceful lifting responsible to weather associated with middle latitude cyclones and hurricanes.

Atmospheric Stability

A property of air that describes its tendency to remain in its original position (stable) or to rise (unstable).

Clouds

A form of condensation best described as visible aggregates of minute droplets of water or tiny crystals of ice. They provide a visible indication of what is going on in the atmosphere and are classified on the basis of form and height.

Cirrus Clouds

High, thin, and delicate clouds that are also called mares’ tails. Thin and white/made up of ice crystals and are Not considered precipitation makers.

Cirrocumulus Clouds

High clouds that consists of fluffy masses.

Cirrostratus Clouds

High clouds that have flat layers.

Altocumulus Clouds

Middle clouds composed of globular masses that are denser compared to cirrocumulus clouds; generally associated with snow or light drizzle.

Altostratus Clouds

Middle clouds that are a uniform white to grayish sheet covering the sky.

Stratus Clouds

Low clouds that are a uniform fog-like layer of clouds that frequently covers much of the sky and may produce light precipitation.

Stratocumulus Clouds

Low clouds with a scalloped bottom that appears as long parallel rolls or broken globular patches.

Nimbostratus Clouds

Low clouds that are chief precipitation producers and are associated with forced lift, particularly orographic lift.