week 4-lily Flashcards
what helps us understand circulation patterns of atm, and oceans, storm systems
Coriolis effect
in the northern hemisphere what way does the wind shift (which way does the Coriolis effect shift)
right
- anti-clockwise
in the southern hemisphere what way does the wind shift (which way does the Coriolis effect shift)
left
- clockwise
what is the Coriolis effect
- An effect, not a force
- Ground moving relative to
airborne/waterborne
objects (matter) - creates a deflection of mass (water, air)
why does the deflection happen?
Earth rotates faster at the Equator than it does at the poles – Earth is ‘wider’ (laterally) at the Equator
- Near the poles, the rotational speed is much slower because the circumference is smaller.
Why does rotation at 2 different speeds matter?
2 cities – same line of longitude; need to travel same distance at different speeds
Buffalo disk
- earths “skinner” here
- further north
- spins slower than quito disk
Quito
- at the equator (fat here)
- spins faster here
This change in velocity with latitude
is the true cause of the Coriolis effect.
example of Coriolis effect
Imagine a Spinning Carousel
You’re sitting at the center of a spinning carousel (like the North Pole).
Your friend is sitting near the edge (like the Equator).
The outer edge moves faster than the center because it has to cover a greater distance in the same time.
Scenario 1: Rolling a Ball from the Center (North Pole) to the Edge (Equator)You try to roll a ball straight toward your friend.
But the carousel is spinning underneath the ball.
Since the outer part is moving faster, your friend moves ahead before the ball reaches them.
From your perspective, the ball appears to curve to the right (even though you rolled it straight).
Scenario 2: Rolling a Ball from the Edge (Equator) to the Center (North Pole) Your friend tries to roll a ball straight to you. Since they started on a faster-moving part of the carousel, the ball carries extra motion.
The ball moves ahead of you, curving to the right again.
Global atmospheric circulation patterns; Coriolis effect
- Create global wind belts that are bent to the right in NH and to the left in SH
- we have different circulation cells and the air is getting bent by the Coriolis effect
what are the 3 circulation cells
- polar cell
- ferrel cell
- hadley cell
Polar Cells (Dry Polar “Deserts”)
- At the poles, the air is cold and dense so it sinks.
- Sinking air forces it to move away from the poles toward the Equator.
- As the air warms and travels, it becomes drier, creating polar deserts or dry conditions around 30° latitudes (the horse latitudes).
Ferrel Cells
- Between 30°–60° latitudes, the air from the Hadley and Polar Cells meets, and the warm air from the tropics and cold air from the poles causes storms and rising air
Hadley Cells
- At the Equator, the sun heats the air, making it warm and light. This causes the air to rise.
- Rising air leads to low pressure and forms clouds and precipitation
- more rising air forces air away from equator, travels toward 30° latitude, where it cools, and then descends
north pole
polar deserts
60 degrees north
temperate forests
30 degrees north
horse latitudes deserts
equator
tropical forests
too look at circulation cells
slide 12 lecture 4
Polar Jet and Subtropical Jets are?
are fast-moving air currents that occur in the upper atmosphere (in the troposphere) and play a significant role in weather patterns around the world
Polar Jet
narrow band of strong winds that occurs at high altitudes (up to 400 km/hr)
- Can and do merge at different points in space and time, also interruptions
- forms at the boundary where the cold polar air meets the warmer mid-latitude air.
subtropical jet stream
- narrow band of strong winds that occurs at a higher altitude than the polar jet
- slower than polar jet
- boundary of the Ferrel and Hadley Cells.
Series of major wind belts what are they
global wind systems that create patterns of airflow in the atmosphere. The movement of air is caused by differences in temperature and pressure across the Earth’s surface