Global Climates
Weather: short-term condition of the atmosphere
Climate: long-term conditions of the atmosphere, including averages and extremes
3 general climate types:
1. Low latitude
2. Mid-latitude
3. High latitude
First general climate type:
1. Low latitude (Table 7.3)
High temperatures
Consistently long days, high solar angle
Low latitudes (20°N – 20°S)
ITCZ
We will look at 4 low latitude climate groups:
1. Wet equatorial:
Wet, Hot
High ppt all months; little temperature variation
ITCZ dominates
Tropical Rain forest vegetation
2. Monsoon and trade-wind coastal
North and south of wet equatorial
Windward coasts in tropics
Wet and dry seasons
1-3 months < 2.5 inches rain
Wet when ITCZ dominates
Dry when ITCZ leaves; High pressure
3. Wet-Dry Tropical
surrounds 1, 2 on map
3-6 months < 2.5 inches
hot dry winter; hot wet summer
semiarid to arid
Savanna vegetation
4. Dry Tropical
Low ppt.; high daily range in temperature
Second general climate group:
2. Mid-latitude Climates (Table 7.4)
Range from dry to moist
Mild winters
Midlatitudes
Most in Northern hemisphere
Seasonality
Shifting air masses (mT,mP,cP); High and Low pressure centers
We will look at 6 of these climate types:
1. Dry subtropical
Cool/cold season
Low ppt all months
Dominated by cT
2. Moist Subtropical
Winters above freezing
High temp range
Abundant rain from mT
3. Mediterranean
hot / warm summer
west side of continents
Wet, mild winter
dry summer
4. Marine west-coast
Poleward of Mediterranean climate zone
precipitation all months; winter max (mP)
small temp. range (moderated by proximity to ocean)
humid
5. Dry midlatitude
Very large range in temp
Low ppt with Summer max
6. Moist continental
Warm summers, cold winters
(3 mos. < freezing)
Large temp. range (continental)
Plenty of ppt (summer max)
Polar front zone (cP and mT)
Third general climate group:
3. High-latitude Climates (Table 7.5)
northern hemisphere (except for ice sheet)
frequent midlatitude cyclones
low temps and low ppt.
We will look at three of these climates:
1. Boreal Forest Climate
Cool, short summer
Long, severely cold winters
6-7 mos. < 32oF
high annual temp. range
dry
2.. Tundra
predominantly N. Hemisphere
long periods of light and dark
short summer (<40oF)
dry
treeless
3. Ice Sheet
Poleward of 32o F isotherm
every month < 32o F
glacial ice
extremely dry