Environmental Science

Humidity Moisture content of the atmosphere Relative Humidity ? the percentage of saturation of the air. 50% humidity means that the air is holding half of the water it is capable of holding 100% humidity is when the air is holding all of the water vapor it can possibly hold ? air is fully saturated and probably precipitating This represents a parcel of air 20 ?C 0 ?C 10 ?C This is moisture 20 ?C HOW FULL IS IT? How could this air mass become 100% full? 10 ?C 0 ?C 20 ?C Drop its temp! What are two ways that nature changes R.H.? What is the Dew Point Temperature? The temperature to which the air mass must drop down to so that R.H is 100% At this point the air is said to be SATURATED

What are 3 major variables that affect our weather? WATCH THE VIDEO! Factors that affect Temperature What is moisture? Water found in one of its three forms: 1. SOLID (ICE/SNOW) 2. LIQUID (RAIN) 3. GAS (WATER VAPOR) Precipitation is moisture that FALLS from the atmosphere above. Precipitation cleans the atmosphere of condensation nuclei Why does precipitation occur? Air can only hold a certain amount of water vapor before it will overfill and condense This is known as capacity ROOM FOR ONE MORE???? What temp. air can hold more W.V.? Warm air can hold MORE water vapor WHY????? Cold air holds LESS water vapor Every 10 degree Celsius increase doubles the air?s capacity Every 10 degree Celsius decrease cuts capacity in half * * * * * * * * * * * * *

What about clouds? What are clouds? Large masses of millions of water droplets suspended in air Water evaporates from lakes, streams, and oceans and enters into the air Transpiration ? the loss of water from plants through their leaves Evapotranspiration ? combines evaporation and transpiration Example of Transpiration: Cloud Forest Steps involved in cloud formation: ?..Warm, MOIST air RISES ?.a drop in air pressure causes?.. ?.Expansion and the air Cools .... Water vapor then?.. ??..Condenses on?? ?..Condensation Nuclei (a surface upon which condensation droplets can stick on. Ex: dirt, salt, smoke) ??..Clouds form!!! Condensation Nuclei Size comparison between raindrop and condensation nuclei Cirrus clouds ? High altitude clouds Cumulus Clouds