Lecture Notes: CH 18–18.1Water in the Atmosphere

Precipitation - ______of water that falls from a cloud.

Water vapor - ______in the atmosphere.

Solid to liquid - ______in the form of heat (ice melt)

Latent heat - energy ______during a ______in state.

Evaporation is the process of changing a ______.

Condensation – gas (______) changes to a liquid (water).

Sublimation - conversion of a ______without passing through the liquid state.

Deposition - conversion of a ______.

Humidity - ______vapor in air.

Air is saturated when it ______of water vapor that it can hold at any given temp. & pressure.

When saturated, ______water vapor than cold saturated air.

Relative humidity - ______of air’s ______water-vapor content compared with amount of water vapor air can hold at that temp. & pressure.

Relative Humidity ______.

Dew point – temp. to which a parcel of air ______to reach saturation.

Measuring Humidity - ______- measures relative humidity.

Psychrometer - a hygrometer with dry- and wet-bulb thermometers. Evaporation of water from the wet bulb makes air temp. appear lower than the dry bulb’s measurement. The two temps ______.

When the temperature reaches the dew point, what happens? ______

With regards to weather, the most important gas in the atmosphere is ______

18.2 Cloud Formation

Air Compression and Expansion

Adiabatic Temperature Changes (when ______or subtracted) – when air expands  cools

______.

Expansion and Cooling

Dry adiabatic rate - rate of cooling/heating for unsaturated air (______).

Wet adiabatic rate – (after condensation begins)rate of change in saturated air (_____

Processes That ______-______mechanisms cause air to rise:

1)Orographic Lifting - ______act as barriers to the flow of air, forcing ____

(______= rainfall on windward side, no rain on leeward side).

2) Frontal Wedging - Front - ______two adjoining air masses

3) Convergence - air ______& rises.

4) Localized ______lifting - unequal surface heating causes pockets of air to rise __

Stability - Density Differences

Stable air tends to remain in its original position, ______(and fall).

Stability Measurements - The rate of ______of air temp. with height is called environmental lapse rate (______rate).

 Degrees of Stability• Temperature ______- a layer where the temp.______rather than decreases ______.

EX) ______during the summer (hot ______smog)

Condensation - For any form of condensation to occur,______.

Generally, must be a ______for water vapor to condense on to (like a leaf) or …

Condensation ______- ______of particulate ______that serve as surfaces on which water vapor condenses when condensation occurs in the air.

3 things needed to ______:

1. Water vapor 2. Condensation nuclei (______) 3______surface

18.3 Cloud Types & Precipitation - Types of Clouds

Clouds classified based on their ______

Cirrus (cirrus = ______of hair) - high, white & thin.

Cumulus (cumulus = ______) consist of rounded individual cloud masses.

Stratus (stratus = ______) sheets or layers that cover much or all of the sky.

Fog - cloud (base at or ______).

Fog Caused by ______- as air cools, becomes ______areas such as river ______, where thick fog accumulations may occur (______).

Fog Caused by ______- cool air moves ______, moisture may ______from water surface to produce saturation. (______)

Cloud names come from what characteristics? ______