Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
ATMOSPHERE Part 2 Water Cycle Air pressureweight of the atmosphere 1. Caused by gravity 2. 14.7 lbs/ sq.in at sea level Barometer- instrument to measure air pressure MERCURY Two types: ANEROID Clicker • What causes air pressure? a) b) c) d) Gravity Inertia Radiation Friction SMART Response Ques To set the properties right click and select SMART Response Question Object->Properties... Units of Measurement 1.Millibars- unit on national weather map 2.Inches of Mercury on local weather 1.Conversion- 29.92’’= 1013.25 mb Latent heat • Energy absorbed and stored in molecules “hidden” Homework • Define/ research: – Psychrometer Psychrometer Instrument to measure humidity Dry bulb – measures air temp. Wet bulb – has a water soak wick around the bulb – water evaporates – cools the air Psychrometer Dry air - greater evaporation - greater cooling - greater the difference in the 2 temperatures High humidity – no evaporation (saturated air) - temperatures of the 2 bulbs will be the same or very close Chart: things that can change air pressure Humidity The more water vapor in the air the lower the air pressure Dry air is more dense H20 is molecularly lighter than N2, O2 and CO2 Specific Humidity ACTUAL Saturated Air amount of At a steady temperature the water vapor in amount of water vapor is at it’s the air at a peak (maximum) given time and Rate of condensation = Rate of evaporation place Units - g of water vapor / Kg of air • Dependent on air temperature • Higher the air temp. - greater the amount of water vapor in the air Relative Humidity Comparison of the specific humidity and the maximum amount of water vapor that the air can hold at a given temperature and pressure UNIT - % Relative humidity = specific humidity X 100% maximum capacity(saturated) 100% Rel. Hum. – saturated air 0% Rel. Hum. – dry air Clicker At any given temperature , 1m3 of air can hold 10 g of water vapor. What is the relative humidity at that temperature if 1 m3 of air is holding 9 g of water? SMART Response Question To set the properties right click and select SMART Response Question Object->Properties... Clicker Dry bulb=22 degrees: Difference between bulb readings is 5 degrees what is the RH %? SMART Response Questi To set the properties right click and select SMART Response Question Object->Properties... things that can change air pressure Altitude ( elevation )As altitude increases; air pressure decreases Fewer gas molecules= less pressure Greatest at sea level or below Least at the top of mountains things that can change air pressure Temperaturewarm air becomes less dense than cold air – Becomes a low pressure • As temperature increases air pressure decreases • Cold air will be a high pressure Dew point: The temperature air must be cooled to in order to reach Saturation. Any point below water vapor will condense into liquid water. If dew point falls below freezing point of water we get FROST. Cloud Formation Clouds are made of which two states of matter? Water Vapor (gas) Liquid water Clicker Water needs to condense on a solid surface there are no solid surfaces in the atmosphere. Using what you know about scattering, what is needed to allow water vapor to condense into a cloud? a) Light b) Dust c) UV rays d) Mesosphere SMART Response Ques To set the properties right click and select SMART Response Question Object->Properties... Condensation nuclei Dust, ice, salt, and other solid particles suspended in the atmosphere. What else is necessary to form a cloud? *Hypothesis* Cloud formation: 2 methods Method 1: Convective cooling ○ The lowering of the temperature of a mass of air due to rising and expanding. ○ Most clouds form this way Temperature changes that occur this way are called Adiabatic temperature changes. Describe and Diagram Method 2: Force lifting Cloud formation requires rising air lifting can come from air forced up terrain, air being heated and becoming buoyant, frontal systems passing through, etc. Clicker How are most clouds formed? a) Force lifting b) Advective cooling c) Convective cooling d) Coalescence SMART Response Quest To set the properties right click and select SMART Response Question Object->Properties... Describe and Diagram: Frontal lifting Describe and Diagram: Orographic Lifting (Barrier) Cloud Identification: the basics Cumulus “Puffy” thick high topped clouds Formed by rising moist air that cools Stratus “sheet” like Form when warm moist air lie above a layer of cool air Cirrus “feathery” highest clouds Form above 6000 m (19685 ft) Prefix/ Suffix Alto: Middle Cirro: Curly Nimbo/nimbus: Rain Precipitation Rain: liquid water in the form of droplets Freezing Rain: rain that falls when surface temperatures are below freezing. Snow: precipitation in the form of flakes of crystalline water ice that falls from clouds. Sleet: form of precipitation consisting of small, translucent balls of ice. Ice pellets are usually smaller than hailstones Hail: solid precipitation. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Rain making processes Coalescence Different size water droplets Combine to form larger Supercooling Water droplets commonly remain as liquid water and do not freeze, even well below 0 degrees. Freezing condensation nuclei Cloud seeding: form of intentional weather modification dispersing substances into the air that serve as cloud condensation or ice nuclei.