Download
1 / 15
150 likes | 263 Vues
Weather and Climate Notes. May 20, 2010. I. Weather Fronts. A. Weather : state of atmosphere that changes day to day 1. Air mass : a large body of air where temperature and moisture content are similar throughout
E N D
Weather and Climate Notes May 20, 2010
I. Weather Fronts A. Weather: state of atmosphere that changes day to day 1. Airmass: a large body of air where temperature and moisture content are similar throughout a. Movement of air occurs according to density—warm air rises and cold air sinks
B. Fronts and Severe Weather 1. Front: the boundary between air masses of different densities and usually different temperatures a. 3 types: Warm front, Cold front, & Stationary 2. Warm Front: a mass of warm air moves toward and over a slower mass of cold air a. As it is pushed up over cool air, it cools & forms clouds 1. Can cause steady rain for 1-2 days b. Red line with red semi-circles on weather map
3. Cold Front: forward edge of a mass of cold air moves under a slower mass of warm air and pushes it up a. High winds, thunderstorms, & tornadoes can accompany front b. Blue line with blue triangles on weather map 4. Stationary Front: occurs when two air masses meet but neither is displaced, instead air masses move side by side a. Weather similar to conditions during a warm front
II. What drives the weather? A. Energy Transfer 1. Energy is transferred between the lithosphere and the atmosphere through the ocean (hydrosphere) a. Energy transfer creates weather conditions b. Interactions of atmosphere with geographiclocations,landforms, and other fronts create convection currents that transfer thermal energy
B. Sea and Land Breezes 1. Sea & Land Breezes results both from wind currents in the coastal air and differences in the specificheats of water & land a. Specific heat refers to the ability of a substance to absorb energy as heat
2. Sea Breezes (Daytime) a. Temperature of the land increases more than the temperature of the ocean b. Resulting in a highertemperature of air over the land than air over the water c. Causes warm air over the land to rise & cool ocean air to move onshore to replace the rising warm air=Sea breeze
3. Land Breezes (Nighttime) a. Temperature of the dry land decreases below that of the air over the ocean b. Warm air over the ocean rises and cool land air moves offshore over the ocean=Land breeze
III. Climate A. Climate: average weather in an area that is measured over many years 1. Does not change day to day
B. Factors that Affect Climate 1. Tilt and rotation of Earth a. Earth’s orbit is an ellipse 1. Closest to the sun on January 3rd and farthest from the sun on July 4th
b. Earth’s tilt is more important because it results in the sun rising to different heights causing different seasons 1. Summer solstice: June 21st (longest day) 2. Winter solstice: December 21st (shortest day) 3. Vernal (spring) equinox: March 21st (day & night are equal length all over Earth) 4. Autumnal (fall) equinox: September 22nd (day & night are equal length all over Earth)
2. Latitudes a. Temperature is higher at the equator 1. More energy is concentrated at the equator because the Earth’s surface is curved 2. Equator is close to being perpendicular to the sun throughout the year b. Because of Earth’s tilt, your latitude will determine the seasonal weather for your location
3. Landforms: Earth’s surface features a. Mountains 1. Warm air cools as it rises along the mountain creating clouds and rain (loses moisture) 2. Cool dry air from the mountain will warm as it descends (falls) down the other side of the mountain a. Air has less moisture because released it on the other side b. Creates deserts on this side of the mountain = RainShadow
3. Landforms (cont.) b. GreatPlains: broad flat surfaces 1. Do not stop wind flow 2. Mixing winds from several directions results in storms and tornadoes=tornado alley
3. Landforms (cont.) c. LakeEffect 1. In winter, warm lake water allows cold air moving over to pick up moisture 2. Then when the moist air mass cools over land, snowfall occurs
