Climatic Processes Flashcards
What is insolation?
Incoming solar radiation (important for temperature and rainfall)
Briefly explain insolation
Incoming solar radiation is more direct at the equator, and is more diffused at the poles. The sun is more powerful or concentrated at the equator, due to the curvature of the earth.
E - pole (more diffuse and oblique)
EE
EEE
EEEE
EEEEE - equatorial (more concentrated and direct)
EEEE
EEE
EE
E - pole (more diffuse and oblique)
What does ITCZ stand for?
Inter-Tropical Convergence Zone
What does a Hadley Cell show?
The movement of air and pressure throughout the atmosphere.
Low pressure High pressure
↓←←←←←←←←←←←←←←←← ITCZ
↓ ↑ ITCZ
↓ - Cold, dry air Warm air rises - ↑ ITCZ
↓ descends ↑ ITCZ
↓ ↑ ITCZ
↓→→→→→→→→→→→→→→→→ ITCZ
High pressure Low pressure
30°N 0°
Is the air warm or cold at 0°? Which end has high pressure and which end has low pressure?
The air is warm because of the intense heating of the sun at the equator, which creates rising hot air. There is low pressure at the bottom and high pressure at the top, with the ITCZ in the middle.
High pressure ITCZ ITCZ ITCZ ITCZ ITCZ Low pressure
Explain what happens in the Hadley Cell
At 0° (equator):
- The hot air rises (low pressure)
- The hot air cools
- The air condenses
- Clouds are formed
- Precipitation occurs (high pressure)
Going from 0° (equator) to 30°N (Egypt) or 30°S:
- Same as above^
- Pressure decreases (goes from high to low)
- Air becomes cold and dry
- Pressure increases (goes from low to high)
- The cold, dry air descends
- Pressure decreases (goes from high to low)
- Back to the beginning at 0°
Why are there high/low pressures at 0° and 30°N?
It’s due to the pressure belts in relation to the Hadley Cell. The Hadley Cell is located in between a high pressure belt and a low pressure belt, causing the respective pressures.
High pressure belt (30°N)
Hadley Cell
Low pressure belt (0°)
What is the pattern of wind between 30°N and 0°?
Trade winds come from the northeast blowing towards the southwest. Monsoon winds blow from the northeast for six months and from the southwest for six months.
Explain the ITCZ
- The ITCZ moves up and down through the tropics, bringing rain with it
- The ITCZ brings the wet season of the year for countries in the tropics
- The July ITCZ moves up towards the Tropic of Cancer, which creates the northern hemisphere’s wet and rainy season (summer)
- The January ITCZ moves down towards the Tropic of Capricorn, which creates the northern hemisphere’s dry season (winter)
- The ITCZ passes some countries twice, bringing intense rainfall as it moves from place to place between seasons
What are the most important characteristics of climate?
Temperature and rainfall
What are the key aspects of temperature?
- The temperature range (the ‘hotness’ or ‘coldness’ of a climate)
- The changes of temperature over different time scales (eg, day/night (diurnal) and seasons)
What does temperature depend on?
- Latitude
- Location relative to the ocean
- Relief
- The amount of solar energy reaching the earth’s surface
What does the intensity of solar radiation depend on?
- The intensity of solar radiation reaching the earth depends on the distance it travels through the atmosphere, as light can be scattered and reflected as it passes through the atmosphere
- It also depends on the angle of incidence (sun’s angle), the angle at which the sun’s rays strike and the surface of the earth
How does the curvature of the earth affect solar energy?
Because of the curvature of the earth, solar energy reaching equatorial regions passes through less atmosphere than solar energy reaching regions of higher latitudes.
When is incoming solar energy the most intense?
When the sun strikes the earth’s surface at a 90° angle
