Meteorology


 * //__Different Meteorology__

//**//**The Study of the Entire Atmosphere, Including its Weather.**

-air is a mixture of many gases in Earth's lower atmosphere -nitrogen and oxygen together form about 99% of dry air by volume -the remaining 1%is mainly argon and carbon Dioxid **e**
 * The Atmosphere**


 * Structure of the Atmosphere**
 * -troposphere-**** is the lowest layer of the atmosphere (0-12 km) in which all of Earth's weather occurs **//


 * gradually decreases in temp with an increase in altitude
 * contains all weather vapor
 * the jet stream is located between 6-12 km

-**tropopause-**the top of the troposphere where the decrease in temp stops - **stratosphere**- reaches from the tropopause to about 50 km above Earth
 * steady winds and few weather changes (PLANES FLY HERE!)
 * steady increase in temp with the increase of altitude, which is caused by absorption from the zone.

-**ozone-**ultraviolet rays make oxygen O3. The Ozone Layer absorbs sun's uv rays and protects us from burning. - **mesosphere**- temperature drops again - **Thermosphere**- temperature rises again about 500 km from Earth
 * -stratopause-**the top of the stratosphere where the temp stops rising.

-the state of the atmosphere at a given time and place -to try to predict weather you need to observe the clouds, wind, temp., humidity, air pressure and precipitation over a period of time
 * //Weather//**

-energy from the sun results in changes in the weather. Heat moves through the atmosphere in three ways //**
 * //Heating of the Atmosphere
 * **// conduction -an object receives heat when it comes into contact with a hotter object (ex. a plain) //**
 * **// radiation -hot bodies radiate energy in short waves (sun); cold bodies radiate energy in longer waves (Earth) //**
 * **convection**-most effective; the rising of hot air and sinking of cold air results in a steady flow. Convection is very important in moving heat through the atmosphere

-solar energy that reaches the earth; we receive one two-billionth of the sun's rays.
 * //__Insolation__//

**//GreenHouse Effect//
 * - short ultra violet waves from the sun are able to reach the earth's surface, then longer infrared waves re-radiated by the Earth's surface are trapped by greenhouse gasses. (CFC'S and CO2) **
 * Normal Lapse Rat**e-** the rate of cooling with Altitude( 1ºC for every 160 Meters) **
 * Temperature Inversion**-** when the air os especially still cooler air, because of it's greater density, settles close to the ground, and the warmer air forms a blanket above it in a temperature aversionpollutants in the air such as soot and smoke are also trapped close to the ground **

//**Specific Heat** -// the amount of heat required to raise the temp. of something 1º C //**w**////**ater has a very high specific heat compared to soil**//


 * **absorption**-take in energy and heat it up
 * **reflection**-bounce back energy
 * **re-****radiation**-absorb short wave energy and give off long wave energy


 * //Heating of Land and Water

water warms much more slowly than land //** -in water, the sun's rays go to a depth of many meters. On land, the sun's rays heat only the top few centimeters of soil. -water can spread heat easily because it is a fluid -some solar energy is used in the process of evaporation. Thus, less solar energy is available to raise the temperature of the water. -water cools more slowly than land because its heat is spread through a greater depth.

//**Temperature**// -a measure of the energy of molecules. The more energy the molecules in air have, the hotter it feels. -temperature is measured in degrees (Celsius, Fahrenheit, Kelvin) -**thermometers-**are the instruments used to measure temperature (alcohol or mercury inside, digital) -**thermographs-**self-recording thermometers
 * -isotherms-**lines drawn on maps connecting places with the same temperature

-// the change from liquid water to water vapor -water vapor is spread throughout the troposphere by convection currents and winds.
 * //Evaporation

**//Humidity -the capacity of air for holding water vapor // specific humidity- the amount of water vapor actually present in the air
 * // as air temperature increases so does the amount of water vapor it can hold //
 * relative humidity-**compares the actual amount of water vapor in the air (Spec. Humidity) with the maximum amount of water vapor can hold at that temperature
 * psychrometer-**the instrument used to determine relative humidity

-the change from water vapor to a liquid. This occurs when the temperature drops low enough that the capacity for water vapor in the air drops below the specific humidity. //**
 * //Condensation
 * -examples**- **dew-**water vapor which condenses on surfaces, such as grass, in the form of a liquid.
 * **dew point**-temperature at which saturation occurs.
 * clouds or fogs-**form when the water vapor condenses into droplets.

Water vapor needs to condense to something!!
 * air may be cooled below its dew point in many ways:**
 * contacting a cooler surface
 * radiating heat
 * mixing with colder air
 * expanding when it rises
 * Condensation Nuclei-**tiny particles, such as salt, sulfate, or nitrate particles, on which water vapor condenses
 * when cooling occurs by contact with a cooler surface, the water vapor condenses directly on that surface

Surface layers of air a few hundred meters thick which are cooled below the dew point. As water vapor condenses tiny droplets stay suspended in the air by the largest air movement -radiation fogs- at night the ground loses heat rapidly. Light winds mix the cold bottom air with the air a short distance from the surface. When the whole layer of air is cooled below the dew point, a fog forms. (Common in humid valleys and near rivers and lakes) //**//advection fogs-**result when warm moist air blows over cool surfaces (ex Coastal Cali)**//
 * //Fogs

Clouds form when air blows above the surface of the dew point

the falling of any form of water from the air to the Earth's surface. //**
 * //Precipitaction
 * occurs when cloud droplets grow into drops heavy enough to fall to the Earth

Different forms of precipitation:
 * Raindrops- form from tiny droplets and then grow by bumping into and combining with other droplets.
 * Sleet-forms when raindrops fall through the freezing air and fall to the ground as pellets of ice
 * Hailstones-begin as a frozen raindrop

The weight of the atmosphere per unit area Differences in air pressure cause the earth's wind and weather changes //**//Pressure decreases with Altitude
 * //Air Pressure

Barometer-**instrument used to measure air pressure**// Falling Barometer- Less Pressure because the air is warm and moist and rises. This can be a sign of precipitation
 * Aneroid Barometer-**measures air pressure with a thin metal can
 * Rising Barometer- greater pressure usually means cooler, drier weather (sinking Air)

Millibar-**metric unit of pressure Standard Sea Level Pressure is 1013.2 MB
 * Isobar-**lines that join points having the same air pressure at a given time (each line is worth 4MB)


 * High Pressure Area (High)-** The area of the largest pressure. The pressure in a high is greater than the surrounding air
 * Low Pressure Area (Low)**- This area has a lower pressure than the surrounding area
 * Pressure Gradient**- The rate of change of air pressure between two points


 * Wind-**the horizontal movement of air form areas oh **HIGH PRESSURE TO LOW PRESSURE.**
 * **the closer the spacing between isobars the stronger the winds**
 * **winds blow across isobars, from high to low.**

Wind flows from areas of high pressure at the poles to low pressure at the equator. **
 * __Global Wind Belts__
 * The wind is deflected by the earth's rotation, called the Coriolus Effect


 * //Air Masses have two characteristics

Temperature depends on whether it comes from the tropics or polar regions. The humidity of the air mass depends on whether it comes from land or sea Air Masses are named from their source region

c-Continenrtal t-Tropical

m-Maritime p-Polar

a-Artic

//**Boundaries between air masses are called FRONTS

Cold Front-// cold air is advancing and is replacing warm air. //
 * cold fronts are steeper and move faster than warm air.
 * air rises upward rapidly forming cumulonibus
 * heavy precipitation and thunderstorms which start and end quickly are associated with cold fronts
 * precipitation covers 75-100 miles and occurs both before and after a cold front passes at the surface
 * cold fronts ravel at speeds between 25-30 MPH
 * as soon as the front passes the temperature will decrease and the wind speed may rise

Warm Front- warm air is advancing and replacing cold air
 * warm fronts move slower; warm air moves up a gentle frontal surface
 * warm air may travel 1000 km before rising 2 or 3 km
 * first cirrus and cirrostratus clouds form and then there are altostratus clouds. Finally, steady rain falls from nimbostratus clouds
 * precipitation can occur for 225-275 ahead of where the front touches the ground
 * warm fronts travel at speeds between 20-25 mph
 * warmer temperatures follow the passing warm front.

Occluded Front-where a cold front is advancing and combining with a warm front
 * occluded fronts move the slowest of all (20 mph)
 * these fronts are associated with cirrus and stratus clouds in front of nimbostratus and cumulonimbus clouds.
 * precipitation occurs for about 400 miles, most of which is in front of the frontal boundary
 * cool air is in front, as warm air is forced up by the cold air which follows the passing occluded front.