EAS Flash Cards

What are the differences between Absolute and Relative Humidity?

Absolute Humidity is the absolute measure of vapor in the air, measured by the mass of H20 Vapor (in grams) over a given parcel size (in cubic meters)= g/m^3 (measure of density). It indicates how much vapor is in the air and thus how heavy potential rainfall will be.
Relative humidity is the humidity relative to saturation at a given temperature, the ratio of the actual amount of water vapor in the air to the maximum amount of water vapor required for saturation at that temperature (Actual/Saturation Vapor pressure). It tells us how close the air is to saturation or cloud formation.

What is Vapor Pressure

Vapor pressure is a measure of the tendency of a material to change into a gaseous or vaporous state, and it increases or decreases with temperature. It is measured in density (mass over volume).

What do Mercury and Aneroid Baramoters Measure?

Atmospheric pressure, measured in the height of readings based on the pressure applied to the medium (mercury or aneroid cell).

What is the unit of measure for atmospheric pressure?

Pressure is measured in inches of mercury or millibars (mb)

What do hygrometers measure?

Humidity; they can include psychrometers, chilled mirror hygrometers, and home-use hygrometers.

What is Saturation Vapor Pressure (SVP)

SVP is the vapor pressure of a system, at a given temperature, for which the vapor of a substance is in equilibrium with a plane surface of that substance's pure liquid or solid phase; that is, that vapor pressure of a system that has attained saturation but not supersaturation. It increases with Air Temp. Exponentially.

What is Dew Point Temperature and how is it measured?

Dew point temperature is the temperature at which air is saturated by water vapor and dew begins to form, as temperature approaches its dew point, RH closes to 100%. It is measured in degrees using the formula Td=T - ((100-RH)/5)

Define humidity

Humidity is a direct measure of how much moisture is in the air.

How does Temperature affect relative humidity?

Typically, Relative humidity will inversely reflect temperature. Thus, in the early morning, relative humidity may be 83% when temperature is 10 dg C (w SVP=12 mb), and in late afternoon w/ temp = 27 dg C and SVP = 35 mb, RH=29%.

T/F: Air temperature in tropics in summer is more humid than air in artic areas during winder (In an absolute sense)?

True

How is frost formed?

Frost is formed either by cooling (when air is cooled to dewpoint) or by adding water vapor via evaporation.

What is Radiation Fog?

Radiation fog is a type of fog due to radiational cooling cooling air to dewpoint. It typically forms on clear, calm nights when there's a shallow layer of moist air near the surface overlaid by dry air.

How is Advection Fog formed?

Advection fog is formed when warm air moves (advects) over cool surfaces, such as water so that the surrounding air cools to its dew point. An example would be the Golden Gate Bridge.

What clouds are categorized as High Clouds?

Cirrus, Cirrostratus, and Cirrocumulus clouds (roughly 15-30k ft above ground).

Which clouds are categorized as Middle Clouds?

Altostratus and Altocumulus (formed roughly 6-13k feet above ground)

What clouds are categorized as low clouds?

Stratus, Stratocumulus, and Nimbostratus (found 2-4k ft above grounds).

Which clouds have vertical development?

Cumulus and Cumulonimbus (can range from 2-60k ft above ground.

What do high Cirrus clouds look like? Are they associated with precipitation?

They are white, made of ice crystals, whispy, and have tails blown from high winds. They are not associated with precipitation.

What do Stratus clouds look like? Precipitation?

They are uniformly gray and typically cover the whole sky. They are often found over oceans and resemble a fog that does not touch the ground (Low and Dark). They are not associated with heavy precipitation.

What do Cumulus clouds look like?

They look like cotton, have sharp outlines and a flat base, and they are typically very spaced out (bases are typically 3300 ft or 1 km wide).

What do Cumulonimbus clouds look like? Precipitation?

They are towering due to their vertical development (and latent heat release), and are associated with precipitation and storms. They sometimes look like anvils with flat tops and bottoms but thinner middle.

What are Cirrostratus Clouds? They are very high thin transparent clouds that cause the sun to look as if it has a halo around it.

What do Geostationary Satellites record?

They monitor wind direction and speed in cloudy areas. They orbit a fixed spot on the equator at the same rate that Earth spins.

What does GOES stand for?

Geostationary Operational Environmental Satellite

What are polar-orbiting satellites and what do they do?

They are satellites that rotate the Earth parallel to its meridians (longitudinal lines) and monitor polar regions that are distorted by geostationary satellites, as well as observe every point on Earth twice a day.