Chapter 8 Flashcards
Weather vs Climate
weather is short term and local
climate is long term and regional
early climate classification
frigid, temperate, torrid
koppen climate system
based on annual and monthly average temp and precipitation
Tropical
almost entirely confined to the equator and tropics of Capricorn and cancer
dry
potential evaporation exceeds precipitation
mid latitude
summers are hot and coldest month has an average temp of -3 C
severe midlatitude
winters have at least occasional snow cover with the mean temp going below -3 C; summers are mild
polar
all months have mean temps below 10 C
Tropical Humid Climates
tropical latitudes, winterless climates, little temp change, high humidity; precipitation influenced by ITCZ
Dry Climates
30% of land area worldwide; lack of moisture or uplift; typically in subtropics; marine deserts
mild midlatitude climates
transition between warmer tropical climates and colder severe climates; hot summers, mild winters, high variable precipitation amounts
severe midlatitude climates
northern hemisphere; continentality: far from oceans; long, cold winter and short summer
polar climates
receive little insolation; no average temp over 50; extremely dry but NOT arid
Highland climate
variable; altitude is more significant than latitude; high diurnal temp variations due to dry, thin air
humid continental climate
climate of the US; dominated by westerlies and associated with frequent weather changes; warm summer, cold winter; low precipitation but high at coastal; winter precipitation associated with cyclones, summer with convection
boundary conditions
external factors that Earth’s climate responds to
forcing agents
external factors driving climate change
reasons why climate change happens
- solar output fluctuations: sunspot activity related to solar output
- continents shift positions: this changes patterns of temp, winds, ocean currents, and albedo
- Milankovitch cycle: changes total solar energy arriving at top of atmosphere and distribution of this energy around the globe
- changes in oceans: absorb energy, store energy, transfer energy
- atmospheric changes: volcanoes release aerosols (cool atmosphere) and CO2 (warms the atmosphere)
feedback mechanisms
one factor affects another
positive: feedback magnifies further change in a variable
negative: feedback acts to inhibit further change
pleistocene ice age
- rapid climate change (colder)
- CO2 was low, sea levels low
- caused ice sheets
Holocene Epoch
- changing orbital parameters
- rapid warming: melting of the laurentide ice sheet
- initiated younger dryas event: rapid cooling
medieval climate anomaly
the north atlantic region was unreasonably warm
little ice age
followed the medieval climate anomaly; north atlantic was unreasonably cold
hockey curve
medieval climate anomaly and LIA pictured
Permafrost melting
high albedo reflects as much as 90% of suns energy (positive feedback bc increases melting)
effects of climate change
more wildfires, longer growing season, water vapor in air increases, more intense rainfall, increased flooding
- more hurricanes: increase in intensity
what does hurricane frequency depend on?
el nino (decreases frequency) and atlantic multidecadal oscillation (increases frequency)
isotopes that affect climate change
oxygen 16 and 18
O18 requires more energy to evaporate and condenses faster
Ice cores to determine past climates
- ice cores determine oxygen ratios
- used to obtain temperature data from isotope ratios, provide info on past chem of atmosphere, and past volcanoes
oceanic sediment deposits to determine past climates
- cores include the bones and shells of plankton and other animals
- CaCO3 important for determining past climate
biological methods to determine past climate
fossils: leaf fossils (serrated edge means cooler climate)
plant fossils: used to estimate CO2 concentration
- fewer stoma= high CO2
fossil pollen: widely dispersed; shows record of past vegetation
remnant landforms to determine past climate
the movement of water, the slow-moving of ice sheets expanding across the surface, wave action across coastlines, wind, and floating icebergs carrying debris
