Topic: Moisture in the Atmosphere

Water enters the Atmosphere by A) --- Mainly from Ocean 70% Earth’s surface

Factors Effecting Evaporation Rate a) Surface Temperature Increases  ---

b) Surface Area Increases  --- Puddle APuddle B Evaporation

c) Humidity increases  --- Lake Evaporation Air is filled with water, no more evaporation.

d) Wind Speed Increases -> --- Lake

B) --- Evaporation and Transpiration = Evapotranspiration

Water is found in all phases in the atmosphere 1) Solid – Clouds, snow 2) Liquid – Clouds, rain 3) Gas - Water vapor

How do we measure moisture in the Atmosphere How do we measure moisture in the Atmosphere

Humidity

Relative Humidity

Dew Point

What happens when the air temperature and dew point are the same? Condensation

Sublimation / Deposition FROST SNOW

Tools used to find Dew Point & Relative Humidity

Measuring Relative Humidity Today you need your ESRT out

Dew Point & Relative Humidity Charts Best Friend - pg 12

The “Dry Bulb” = Air Temp Don’t let it fool you. It is just a thermometer. Don’t let it fool you. It is just a thermometer. 20°C

The “Wet Bulb” Has a little wet booty tied to the bottom. Has a little wet booty tied to the bottom. Gets cool when water evaporates. Gets cool when water evaporates. 12°C Wet Booty

A Dry Day… A lot of moisture will evaporate. A lot of moisture will evaporate. The wet bulb will be a lot cooler than the dry bulb. The wet bulb will be a lot cooler than the dry bulb. 8°C 20°C Difference between wet bulb & dry bulb is 12 °C. 20°C14°C 12°C

A Humid Day… A little bit of moisture will evaporate. A little bit of moisture will evaporate. The wet bulb will not be much cooler than the dry bulb. The wet bulb will not be much cooler than the dry bulb. 14°C 20°C Difference between wet bulb & dry bulb is 6 °C.

Dry-bulb temperature = air temperature. 20 °C

14 °C

Subtract (the difference) between the dry bulb and wet bulb

14°C 20°C 20-14=6

16°C 18°C 18-16=2

8°C 20°C 20-8=12 Put it all together Relative Humidity = 11%

10°C 14°C 14-10=4 Relative Humidity = 60%

10°C 14°C 14-10=4 Dew Point = 6°C The Dew Point Chart works the same way

Try These. Dry Bulb Wet Bulb R Humidity DPT 26°C 20 °C 14 °C 0 °C -3 °C % °C % %

Dry Bulb Wet Bulb R Humidity DPT 21°C19°C 17 °C 17°C 70°F 60 °F % °C % %