1. Chapter 11- Tropical climates
Tropical climates are somewhat variable
In terms of moisture
In terms of temp on a day-night cycle
And somewhat consistent
In terms of annual temp
In terms of incoming solar radiation

2. Diurnal compared to annual temperature ranges defines the tropics

3. Tropics (shaded land) have a greater diurnal temperature range than annual temperature range

4. Moisture is what indicates classification and prevalent life forms in the tropics
Af climate - dominated by mT airmasses wet all year round; rain forest biome
Aw, Am, BSh climates - dominated by alternating mT and cT airmasses; wet season vs dry seasons; savanna biome
BWh climate - dominated by cT all year; dry all year; desert biome

5. Hadley cell circulation is critical toward understanding tropical climates
controls location of ITCZ (rising, unstable air- Low pressure)
shifts north or south with seasons
shifts to accommodate land vs water
Controls wet vs dry seasons in tropical climates with that trait.
Controls location of permanently dry regions by location of sinking air (High pressure)

6. ITCZ extremes in geographic position

8. Moisture plays a critical role in temperature
too much --> cools temps considerably by blocking incoming radiation and lowering surface temp
too little, and temps plummet at night as no water in the atmosphere to catch outgoing longwave radiation coming the land surface

9. ITCZ means converging air, moist air, rising air, unstable air, low pressure and precipitation
Temps are moderated in the rain forests
not the blazingly hot jungles often portrayed in Hollywood
still warm, and definitely muggy
“feels” much warmer due to high relative humidity.
humans cooling system thwarted

10. Amount of rainfall varies, but the frequency is more important that the amount
Daily rainfall events are somewhat different than in the mid-latitudes
Thunderstorms dominate all year round in tropics
more intense, but shorter lived and more frequent than mid latitude cyclonic storms with fronts

11. Common diurnal rainfall in the tropics

13. The tropical rainforest
Species diversity- one of the most diverse environments on the planet
One hectare can contain 200+ species of trees
Stratified system enables numerous micro-climates within the forest
Global benefits biomass production is immense
Oxygen production is matched only by marine organisms, but per capita is unmatched

14. Sometimes “helped” by oceanic or mountain systems
Tropical deserts
found in persistent high pressure zones associated with Hadley circulation cells
Tropical deserts have relatively higher temps than do mid-latitude deserts
Sometimes “helped” by oceanic or mountain systems
Can cover extremely large areas
Sahara
3500 k mi2
Australian
1300 k mi2
Kalahari-Namib
220 k mi2

15. Cold ocean currents affect desertification
Cool air holds less moisture
Cool air sinks (stable conditions = high pressure)
Stable air + low moisture = low rainfall
Coastal South America (Chilean desert)
Coastal south Africa (Namib desert)
Western Mexico (Baja Peninsula)

16. Tropical deserts are extremely sensitive to climate change
One of the first climate zones to feel the effects of changes in global climates
wetter = plant growth explodes
lakes and rivers form
animal and people inhabit
drier = desert expands
surface moisture diminishes
animals and people adapt, leave
or die

17. Desert storms
not much in the way of rainfall
very windy because of few obstructions and severe thermal lifting
creates sandstorms and dust devils

19. Pre-colonial
Post-colonial