Weather Notes Weather Weather is the of the Earth s atmosphere at a place and time It is the movement of through the atmosphere o Energy comes from the The sun is the force that weather The sun s energy with earth s atmosphere in the atmosphere o 50 % by earth s surface. This heats the land and water o Some absorbed energy is back to the atmosphere. As infrared radiation o 5% is by the surface back into the atmosphere o 20% is absorbed by and particles in the atmosphere o 25% of incoming sun is by dust, clouds, & particles Heat Transfer Conduction: direct from one substance to another (touching) Radiation: direct transfer of by electromagnetic waves (through space) Convection: transfer of heat by the movement of (liquid or gas) Wind Wind is the movement of air from an area of pressure to an area of pressure pressure Low
Difference in pressure o Caused by the heating of the atmosphere The air (by equator) rises The cool air or rushes to replace the rising air Measure wind o Use anemometer unit of m.p.h. (miles per hour) Wind chill: the blowing of wind on your skin makes you feel Local Winds Local winds: winds that over a small area Caused by unequal heating in a area o Examples Sea Breeze: cool air blows from toward land where hotter air has risen Land Breeze: land cools than body of water at night Hot air over water and rises air from land rushes in over the water Global winds Global winds: winds that are caused by unequal heating of the o Occurs over areas o Form from giant currents in the atmosphere (Hot up, Cold down) Air pressure at the poles is than air pressure at the equator *PRESSURE DIFFERENCE CAUSES WIND* o Coriolis Effect: global winds due to the rotation of the earth. The Coriolis effect is the way the earth s makes the wind curve Winds in North curve toward equator Winds in curve left toward equator Calm Areas o Doldrums: area near the The hot air rises and is replaced by cold air, but the cold air is heated so there is not much horizontal movement o Horse latitudes: occur at 30 o North and South of equator Cool air sinks: very area
Global wind Belts o Trade winds: blow from the horse latitudes toward the Used for routes o Polar easterlies: Cold air near the poles sinks and back toward the lower latitudes Coriolis effect these winds so they meet prevailing westerlies Creates the front o Prevailing westerlies: occur in the mid-latitudes (30 o -60 o N & S) These blow towards the Very important to in the USA Jet Stream: bands of high speed air 10 km the earth (200-400 km/hr) o Blow from West to East Water in the Atmosphere Humidity Humidity: is a measure of the in the air o Warm air can hold H 2 O vapor than cool air Relative Humidity: The amount of water vapor the air can hold at a particular time Dew Point: The temperature where condensation o When water vapor to liquid water Clouds Clouds form when water vapor in the air to form liquid water or ice crystals o Condensation occurs when the changes and has small particles to rest on Dew: condensation on a Frost: condensation on a surface at a Temperature below Three main types of clouds o Classified by their o Cirrus: wispy hooked ends only at altitude made of crystals is coming
o Cumulus: white Some indicate weather others indicate (cumulonimbus) nimbus means o Stratus: flat layers can produce, rain or snow called nimbostratus o Altocumulus and Altostratus: clouds o Fog: cloud that forms on or near Air Masses and Fronts Air Mass Air Mass is a huge body of air that has temperature, humidity and air pressure. There are 4 air masses Classified by the and content o Polar: Form north of the 50 o N. Latitude or South of 50 o S. Latitude air pressure o Tropical: air pressure Maritime form in the (wet) o Maritime: Tropical Maritime Forms over (Warm) o Continental: air forms over Polar (Cold) Polar Continental (dry) Tropical Continental Air masses move 2 ways o Streams o Prevailing Front Front: the boundary where air masses Four types of fronts Cold Front: moving o Can have thunderstorms o heavy cold air pushes lighter air upwards
Warm Front: moving o Precipitation o Warm air cold air by sliding over it Stationary Front: Cold air and warm air are at a o Precipitation can for days o warm nor cold air advances Occluded Front: Warm air is between 2 cool air fronts o Very complex o Precipitation o Cold air is cool air at the surface warm caught air above Cyclone and Anticyclone Cyclone: an area of pressure where wind spins counterclockwise o Area of Anticyclone: an area of pressure where wind spins clockwise o dry weather Storms Storms: disturbance in the atmosphere Thunderstorms They form in a cumulonimbus cloud o Thunderheads Form when warm air is forced during a cold front Form on & humid afternoons Storm Movement o Heavy o Strong within the cloud Lightening: particles travel between the cloud and earth
Tornadoes Tornado is a rapidly, funnel-shaped cloud that reaches the earth. Form most commonly in cumulonimbus clouds o Warm moist air from the bottom of the cloud flows (LOW PRESSURE IN CLOUD) Warm air begins to Tornado forms as the funnel Measuring Tornadoes o Fujita scale (F0-F5) Hurricanes Hurricane: tropical cyclone that has of 119 km/hr or higher Formation of Hurricane o Warm air rises around the eye in spiraling bands o Air flow near the top of the hurricane o Cool dry air in the eye Hurricanes form over ocean water o As low pressure area or depression Hurricanes move in the by the Easterly Trade Winds Storm Surge: a of water that sweeps across the coast where the hurricane lands.
Lake effect Snow: Cool dry air mass moves over a body of water and up water vapor Snow after the water vapor condenses again. Climate Scientists use two main factors precipitation and temperature to describe the of a region Factors affecting Temperature (distance from sea level) Distance from bodies of currents (distance from equator) o World Temperature Polar Zone: climates Temperate zone: warm or hot in, cool or cold in. Tropical zone: climate Factors affecting Precipitation Prevailing Seasonal