Climate Chapter 14
Dec 25, 2015
Climate
Chapter 14
Climate
What is climate?
• What is the definition of climate from Chapter 12?– Long term variations in weather for an area
• What is climatology?– The study of Earth’s climate
Normals• Climate data is compiled
from meteorological records continuously. – This data is averaged on a
monthly or annual basis for 30 years to determine the normals.
– What is a normal?• Standard value for a location• Do not describe daily weather
conditions
Normals
What Causes Climate?1. Latitude: How would latitude
affect climate? Amount of solar radiation received
at any one place differs. What areas receive the most? Tropics
2. Topographic Effects Large bodies of water heat and cool
slowly What does this mean for costal
areas? Remain warmer in winter
What do you think mountain climates are like? Usually cooler due to higher elevation
Latitude
Topographic Effects
What Causes Climate?
3. Air Masses Areas where air masses form have similar climate
to the air mass itself
Climate Classification• Two Factors used:
1. Temperature2. Amount of Precipitation
• Koeppen classification system– Based on average monthly temp. and precipitation
values
Tropical Climates
• Constant high temperatures• Most have large amounts of rain– Some have dry winters (Savannas)
• Dramatic vegetation
Dry Climates
30% of Earth’s land area Largest climatic zone
Deserts Low precipitation Scarce vegetation Hot, tropical air
Mild Climates1. Humid Subtropical: SE United States
Subtropical high-pressure systems over oceans in summer
Warm, muggy weather during the summer
2. Marine West Coast: West United States Constant inland flow of air off ocean Mild winters, cool summers Abundant precipitation
3. Mediterranean: Italy and Spain Warm Summers
Continental Climate Three Zones
1. Warm Summer2. Cool Summer3. Subarctic
Clashing tropical and polar air masses What occurs when this happens?
Tornadoes
Rapid and violent changes in weather; extreme temperatures; A lot of precipitation in summer
Polar Climates
• Coldest regions on Earth• Precipitation is low• Heat radiation by Earth’s surface is low.– Too low to produce strong convection currents– What do convection currents produce?• Heavy precipitation
Microclimate
A localized climate that differs from the main regional climate
Heat Islands Buildings and concrete cause climate to be
warmer than surrounding rural areas Concrete radiates a lot of heat back in to the air
Heat islands
Ice Ages
Periods of extensive glacial coverage. Average global temperature decreases by 5°C Most recent ended about 10,000 years ago
Seasons: short-term periods of climatic change Caused by regular variations in daylight, temperature, and weather patterns.
• Tilt of Earth• Orbit of Earth• Amount of sunlight
Short-Term Climate Change:
Short-Term Climate Change El Nino: warm ocean current
Occasionally develops off South America Warms air on South American coast
Natural Climate Change• Solar Activity
Maunder minimum: low sunspot activity corresponds to unusually cold climatic episode
Earth’s Orbit: varies from circular to elliptical What do you think happens when the orbit goes from
circular to elliptical? Elliptical=Earth passes closer to the sun=warmer temps
Earth’s Wobble: Earth does not always point to the North Star which changes effects of seasons
Volcanoes: How would this affect climate? Volcanic ash can block solar radiation
Greenhouse Effect
Retention of heat by the atmosphere Keeps Earth from getting too
hot or too cold
Global warming: Theory that the release of too
much CO2 in the atmosphere is causing an increase in global temperatures
Deforestation contributes to global warming