C18 F1

Any form of water that falls form a cloud

• "hidden heat"
• measured in joules or calories
• stored in liquied water & not released as heat until liquid returns to solid state
• aids in forming towering clouds seen in summer days
• major source of energy for thunderstorms, tornadoes & hurricanes

• The process of changing a liquid to a gas
• takes ~2500J to convert 1gm of water -> gas

Where water vapor changes to the liquid state

The conversion of a solid directly to a gas, without passing through the liquid state

The conversion of a vapor directly to a solid

The general term fot the amount of water vapor in the air

The number of vapor molecules returning to the surface will balance the number leaving

• The temperature to which a parcel of air would need to be cooled to reach saturation
• For every 10^oC increase, amount of water vapor need for saturation doubles, ie: 0^oC contains ¹/₂ water vapor of saturated air of 10^oC & ¹/₄ water vapor of saturated air of 20oC.
• HIGH dew-point temp = moist air
• LOW dew-point temp = dry air

• The device that measures relative humidity
• ex: psychrometer has 2 similar thermometer mounted side-by-side, one w/ wet cloth; it's swung in air---the drier the air, the more moisture evaporates & the lower the temperature of the wet bulb (because it takes the heat from the wet-bulb as the cloth dries, causing temp to drop)--not as accurate.
• Better to use electric hygrometer, which uses electrical conductor coated w/ chemical that absorbs moisture.

• Increase temp = LOWERS humidity = dry air
• Decrease temp = RAISES humidity = moist air

The process of changing state requires that energy is transferred in the form of heat

Relative Humidity is a ratio of the air's actual water-vapor content compared with the amount of water vapor air can hold at that temperature and pressure.

As the temperature goes up, the relative humidity goes down. The warmer the air is, the more water it can hold(the water is in vapor form). Say its 70 degrees outside, and the relative humidity is 50%. This mean that the air is currently holding half of the water it can contain. Say the temperature goes up to 80 degrees, but the actual amount of water in the air stays the same. The warmer air can now hold more water, so the relative humidity would now be under 50%. So if its 70 and there is 80% relavitve humidity, its less humid than if its 80 and there is 80% humidity..

To summarize, when the water-vapor content of air remains constant, lowering air temperature causes an increase in relative humidity, and raising aire temperatures causes a decrease in relative humidity.

Rate of cooling or heating applied to unsaturated air

Slower rate of cooling caused by the addition of latent heat "hidden" which begans at condensation level

When elevated terrains, such as mountains act as barriers to air flow.Precipitation and cloud formation usually happens and all or most of the humidity is lost before they get to the leeward side

Where warm and cold air masses collide.

The outcome of frontal wedging. Here the cooler, denser air acts as a barrier over which the warmer, less dense air rises.

The most stable air: Air temperature is high with altitude

Tiny bits of particulate matter above the ground

When air is allowed to expand, it cools, and when it is compressed, it warms

Four mechanisms that can cause air to rise are orographic lifting, frontal wedging, convergence, and localized convective lifting

Stable air tends to reamis in its original position, while unstable air tends to rise

For any of these form of condensastion to ocuur, the air must be saturated

Clouds are classified on the basis of thier form and height

High,white, and thin clouds

Clouds Consists of rounded individual cloud masses and is a sign of good weather.

Best describes as sheets or layers that cover much or all of the sky

Fog is defined as a cloud with its base at or very near the ground.

For precipitaion to form, cloud droplets must grow in volume by roughly one million times

In warm clouds, the mechanism that forms raindrops.

The type or precipitation that reaches Earth's suface depends on the temperature profile in the lowest of a few kilometers of thhe atmosphere

• water vapor
• ~ 0 - 4% by volume
• atmosphere only holds ~ 2mm deep global layer

0 - 4% by volume of atmosphere

matter changes from solid -> liquid -> gas, which requires the transfer of energy in the form of HEAT

breaking of water molecules in ice crystals, forming noncrystalline subtance: liquid water

• Warm air can hold HIGH water vapor
• Cool air can hold LESS water vapor

• The ratio of the air's water-vapor content to its water-vapor capacity
• The drier the air, the more moisture evaporates, the lower the temp. of the wet bulb

• Relative humidity is simply the amount of water vapor in the air in relation to how much water vapor that air can hold. Colder air cannot hold as much water vapor as warmer air. Thus, as temperature decreases, the relative humidity will increase, and likewise, as temperature increases, the relative humidity will decrease.
• The warmer the air, the more water vapor it can hold, the higher the RH

water vapor, temperature

It is either absorbed or released:

gas (releases heat) ---> liquid (releases heat)---> solid

solid (aborbes heat)-->liquid (absrobs heat --> gas

• COLD air holds LESS water vapor
• HOT air holds MORE water vapor

The warmer the air, the more water vapor it can hold, the higher the RH

The cooler the air, the less water vapor it can hold, the lower the RH

• HIGH dew point temperatures indicate MOIST air
• LOW dwe point temperatures indicate DRY air.

• air COMPRESS = increase temperature
• air EXPAND = decrease temperature

warm air & cold air collide, producing a FRONT

• orographic lifting- mountains acting as barriers to the flow of air, forcing the air to ascend; the air cools adiabatically, and clous & precipitation may result.
• frontal wedging- when cooler, denser air acts as a barrier over which the warmer, less dense air rises.
• convergence- collsion of contrasting air masses forces air to rise.
• localized convective lifting- unequal heating of Earth's surface may cause pockets of air to be warmed more than the surrounding air.

• stable air = remains in is original position
• unstable air = rises

instrument designed to collect weather data high in atmosphere,often carried by air balloons

• stable air = remains in is original position/ resist vertical movent
• unstable air = rises

When stable air is forced above Earth's survace, the clouds that form are widespread & have little vertical thickness when compared to their horizontal dimension. There might be ligth to moderate precipitation, if any.

condensation nuclei: microscopic dust, smoke, & salt particles from ocean...condensation needs a surface; therfore, dust, smoke, etc are good condensation nuclei

• temperature DROPS when EXPANDS
• temperature INCREASES when COMPRESSED

• Stable air tends to remain in its original position
• Unstable air tends to rise

condensation nuclei must exist

• clouds are classified based on their form & height:
• Cirrus (curl of hair)- clouds are high, white & thin
• Cumulus (a pile)- clouds consit of rounded indivual cloud masses; caulifower structure.
• Stratus (layer)- sheets or layers that cover much or all of the sky

• high - 6000 meters; cirrus, cirrostratus(flat layers), cirrocumulus (fluffy): all high clouds are thin & white & often made of ice crystals; when cirrus clouds ared followed by cirrocumulus or cirrostatus clouds & increase coverage, may indicate approaching stormy weather
• middle- 2000 to 6000 m, have prefix alto; rounded mass, clouds are larger & denser (altocumulus, altostratus)...Altostratus clouds create uniform white to grayish sheet covering the sky with the sun or moon visible as a bright spot; infrequent light snow or drizzle may accompany these clouds.
• low- stratus, stratocumulus & nimbostratus; stratus coulds are unifrom, fog-like layer of clouds that frequently covers much of the sky; occaionally, these clouds may produce light preciptation. nimbus (rainy clouds) stratus (layer): nimbostratus clouds are one of the main precipitation makers.

• physically & structurally are no difference b/t fog & cloud.
• Difference is the method & place of formation:
• Clouds result when air rises & cools adiabatically.
• Fogs are result of radiation cooling or the movement of air over a cold surface.
• Fog is defined as a cloud with its base at or very near the ground.
• Fogs caused by cooling: earth's surface cools rapidly by radiation; thin layer of air in contact w/ the ground is cooled below its dew point.

Cloud droplets must grow in volume by roughly one million times

• types of precipitation that reaches Earth's surface depends on the temperature profile in the lowest few kilometers of the atmosphere.
• temperature profile- the air temperature changes w/ altitude.

• physically & structurally are no difference b/t fog & cloud.Difference is the method & place of formation: Clouds result when air rises & cools adiabatically.Fogs are result of radiation cooling or the movement of air over a cold surface.Fog is defined as a cloud with its base at or very near the ground.
• Fogs caused by cooling: earth's surface cools rapidly by radiation; thin layer of air in contact w/ the ground is cooled below its dew point.

• types of precipitation that reaches Earth's surface depends on the temperature profile in the lowest few kilometers of the atmosphere.
• temperature profile- the air temperature changes w/ altitude.

cloud droplets: combination of microscopic particles: dust, smoke, etc