1. Chapter 4Moisture and Atmospheric Stability

2. Section 4.1: Movement of Water Through the Atmosphere The Hydrologic Cycle (_______________) • amount of water vapor ____________; impact is enormous • water is a ____________________________ • continuous exchange between _________________________________ (powered by the sun)

3. The Hydrologic Cycle

4. Another Look

5. __________________ – liquid  gas • __________________ – water falls from clouds • __________________ – the flow of water over land • __________________– downward movement of water through soil • __________________ – water enters atmosphere from trees and plants • __________________– accounting for the inputs and outputs of water

6. Section 4.2: Water’s Changes of State • ice, liquid and vapor

7. Latent Heat • __________________– the energy absorbed or released during a change of state • __________________ – solid  liquid • __________________ – liquid  solid • __________________ – liquid  gas • __________________ – gas  liquid • __________________ – solid  gas (no liquid stage) • __________________ – gas  solid (no liquid stage) snow and frost

8. Section 4.3: Humidity – Water vapor in the air • ______________________ - mass of water contained in a unit volume of moist air. • _____________ – amount of water vapor in air • _______________________ – compares the actual amount of water vapor in air to the amount air could hold at that temperature _____

9. on a day with ____________________________, air is holding all the water vapor it can _______________ • the ________ the air, the ____________________ it can hold

10. * if moisture is added to air after saturation – _______________ occurs * if air is cooled after saturation – ________________ occurs (fog, clouds, dew, etc.)

12. Measuring Humidity tool: __________________ 1. _________________ – has __________________ mounted side by side - one (__________), one (__________) - air is fanned past it, so H2O evaporates (the drier the air, the more cooling occurs) 2. _________________ – hair _______________ as humidity increases 3. _________________ - uses moisture absorbing chemical - used in radiosondes

13. Psychrometer

14.  in nature, changes in humidity occur as: 1. _____________________________________ 2. _____________________________________ 3. _____________________________________ ________________ – the temperature to which air has to be cooled for saturation to occur - once it is cooled past that point, ______, _______ and _______ occur (depends on temp. > 0°C or < 0°C) _________________________________!!!

15. * recall… condensation forms when air is saturated a) by H2O being added b) by temperature dropping past dew point fog and dew - form by _______________________ - when air expands_______________ - _______ pressure in upper atmosphere; allows air to ________________________________ – makes clouds

16. Clouds – tend to form from __________________________ • when air expands, its cools, when it is compressed, it heats up • Less pressure, air expands, cools and forms clouds!!

17. - an air mass is cooler than surrounding air - more dense, sinks - no/flat clouds temperature inversion - on clear nights, air near ground cools quickly & stays, trapping pollutants fog - low lying stratus (flat) clouds - an air mass is warmer than surrounding air - less dense, rises - clouds hot summer p.m. - pockets of air heated strongly - rises causing clouds - some towering w. heavy precipitation (convective lift) orographic lift - air forced up mountain, cools - lots of precipitation -causes rain shadow desert (leeward) frontal wedging -cool air a barrier, warm air rises Stable air vs. Unstable air

18. 1. ___________________________ - surface heating causes masses (pockets) of air to be warmed more than the surrounding air and rise 2. ___________________________ - occurs when mountains act as barriers to air flow, air is forced up the slope of mountain and cools (lots of rain and snow) rainiest places – windward side of mountain desert places – leeward side of mountain (called rain shadow deserts)

19. 3. ___________________________ - cool air acts as a barrier over which warmer air rises

20. 4. ___________________________ - occurs where air flows together and result in upward movement - forceful lifting (cyclones, hurricanes)