Weather and Climate Unit 5 Chapter 3

I. Weather vs. Climate A. What is weather? A.Weather=condition of the atmosphere at one place for limited time B.Think of weatherman, how far in advance do they give the forecast? C.Weather also includes precipitation which includes rain, snow or sleet depending on air temperature & wind conditions

B. What is climate? 1. Climate= weather pattern over a long period of time 2. Climate is determined by earth’s position in relation to sun

II. Earth’s Tilt and Rotation A. Axis 1.Axis is an imaginary line from north pole to south pole 2.B/C of tilt of earth on its axis, not all places on earth receive same amount of direct sunlight

B. Temperature 1. Due to earth’s tilt, places have different temperature 2. Temperature measures how hot/cold a place is a. More direct sunlight=warmer temp b. measure temp in degrees of Fahrenheit or Celsius 3. Earth also rotates on axis every 24 hours=rotation a. earth rotates west to east and gives us day and night

C. Earth’s revolution 1. Earth travels in orbit around the sun a. it takes 365 days to complete one revolution, or one trip around the sun 2. Revolution also gives Earth its seasons a. seasons reverse north & south of the equator b. depending on Earth’s tilt, some places near the poles have continuous sunlight or complete darkness for days/weeks

III. Greenhouse Effect A. What is it? 1.Atmosphere traps some heat & keeps from escaping back into space too quickly (see pg 70) 2.Need greenhouse effect for most things to live a. Must be regulated

B. Problem 1. In recent decades increase in carbon dioxide (CO2) & general increase in global temperatures 2. Called global warming a. caused by human activity-burning fossil fuels (coal, oil) b. as more fossil fuels burned-more green house gases into atmosphere & trap more heat

C. Effects of Global Warming 1. weather patterns more extreme 2. Water evaporates=more humidity and more rain 3. Water evaporates from soil=drier land

IV. Factors affecting Climate A. Latitude & Climate 1.Each place’s latitude determines its climate region B. Three categories of latitude low latitudes: from N & S latitude (*very tropical, hot climate) Middle Latitudes: From 30 N & S *weather changes according to different seasons Middle Latitudes: From 30 N & S *weather changes according to different seasons High latitudes: (Polar regions) from 60 N & S *cold to freezing climate (almost all year) High latitudes: (Polar regions) from 60 N & S *cold to freezing climate (almost all year)

C. Elevation & Climate 1. As you move up a mountain (increase elevation) your temperature decrease a. Why? Less atmosphere to keep in the heat

D. Wind & Ocean Currents -Wind Patterns 1. Wind=air moving across the surface 2. Prevailing winds is wind that blows in a pattern in a pattern 3. 4 types of prevailing winds: a. Trade winds- located in low latitudes b. Westerlies- located in mid latitudes c. Polar Easterlies- located in high latitudes d. Doldrums-located at Equator, windless (small breeze) windless (small breeze)

Wind & Ocean Currents continued Ocean (water) Currents 1. Currents are warm and cold “rivers” in the ocean 2. in northern hemisphere currents move clockwise 2. in northern hemisphere currents move clockwise 3. In southern hemisphere currents move counter clockwise 4. Warm currents warm the land and cold currents cool the land

E. Landforms & Climate 1. surface features-water & mountains-can also affect climate 2. large bodies of water are slow to heat & cool down than land is 3. Water temperatures are more constant than land temperatures 4. coastal lands receive benefit of water influence & experience less changeable weather than areas inland away from coast 5. mountains also affect precipitation and climate-windward and leeward

Winward- wind blows over ocean & pushed up mountain. Rising air cools and releases moisture (precipitation) Leeward- after precipitation released, wind becomes warmer and drier as descends down opposite side of mountain Result= Rain Shadow hot dry air with little precipitation Rain Shadow effect causes dry area (deserts)

V. El Nino A. What is it? 1.El Nino is recurring phenomenon with periodic change in pattern of ocean currents & water temperatures in the mid Pacific Ocean region a. Mainly affects weather western coasts of North, Central and South America during December/January

B. What happens? 1. Normal low pressure increases & high pressure drops- change in normal weather pattern a. This is an actual reversal in what normally happens in the Pacific Ocean

C. Results/Effect of El Nino 1. Trade winds diminish or reverse directions 2. Due to winds changing get change in ocean currents & warmer water moves along N & S American west coasts 3. Increased precipitation, warmer winters & more flooding in N & S America 4. Southeast Asia and Australia experience drier or drought conditions 5. La Nina also exists & this is when cooler than normal waters move off coasts of North, Central & South American west coasts

VI. Five major climate regions 1. Tropical Climate 2. Dry Climate 3. Mild Climate 4. High Latitude Climate 5. High Altitude Climate **all 12 climate zones fit into these 5 regions

Tropical climates 1.Location=found in low latitudes only a. Rain forest (Tropical Wet) -Rainfall daily (80+inches year) -Hot (average=80 F), humid & muggy b. Savanna (Tropical Wet) -dry winters & wet summers with high year round temperatures -located on outside of rainforest

2. Dry Climates *Location=both found in low & mid latitudes A. Desert (Arid) 1.Sparse plant life 2.Hot during day & night 3.Very dry & very little rain (less than 10 inches/yr) 4.Oasis may exist in desert due to underground springs

3. Mid-Latitude climates *location=all found in mid-latitudes A. Marine West Coast 1. found on west coasts 2. Ocean winds bring cool summers & damp winters 3. Steady rain year round Example: Seattle, England 3. Steady rain year round Example: Seattle, England

B. Mediterranean 1. Zone surround Mediterranean Sea 2. Mild rainy winters & sunny dry summers Example: Italy, Greece

C. Humid Subtropical 1. short, mild winter with year round rain 2. hot summers with high humidity 3. found in Southeastern USA and Southern South America & Asia 4. this is Northern Virginia

D. Humid Continental 1. B/C located more north in the mid-latitudes, can get severe snowy winters & shorter cooler summers Examples: NYC, Chicago

B. Steppe (Semi-arid) 1. Usually surround the deserts 2. Dry mostly treeless grasslands but does receive small amount of rain

4. High latitude climates *location= high latitudes (polar regions) A. Subarctic 1.Bitter, cold winters, but have short cool summer days—Example=most of Alaska and Canada 2.Permafrost-permanent frozen layer of subsoil 3.Taiga=Subarctic evergreen forest covers much of Russia/Siberia

B. Tundra 1. Long, very cold windy winters w/ short Summers Examples: coasts of Greenland & interior of Alaska

C. Ice cap 1. rarely above freezing and land covered by snow/ice 2. coldest climate on Earth-most of Antarctica

5. Highlands climate *location=only climate zone in all 13 latitudes A. High Mountain 1.Zone located across the world in all continents 2.Climate depends on elevation- higher the elevation the cooler the temperature