tropical storms & global atmospheric circulation

what is global atmospheric circulation?

the earths movement of air, by solar heating that distributes air around earth in three loops per hemisphere

hadley, ferrel, polar

hot air rises at the equator (low pressure) cools, and sinks at 30 degrees (high pressure), creating winds

what is the hadley cell

intense solar heating at the equator causes air to rise, forming low pressure belts and heavy rain, this air cools and sinks at around 30 degrees north/south, creating high pressure belts with dry, clear conditions and deserts

what is the ferrel and polar cell

air moves poleward from the subtropical highs meeting cold polar air at 60 degrees north/south, where it rises to create low pressure, rainy, stormy weather

what are surface winds

trade winds flow from the subtropical highs towards the equator, while westerlies move towards the poles

how do tropical storms form?

1. location - between tropics of cancer and capricorn

2. warm ocean temp (27 degrees+)

3. low pressure- warm air rises rapidly, forming clouds and intense rainfall

4. small storms join together, when winds reach 75mph it becomes a tropical storm

5. the storm starts spinning because of the earths rotation (coriolis effect) and eye forms in center, winds get stronger while it moves across the ocean, absorbing energy from the water

6. it hits land and weakens because it no longer has warm water to fuel it

why are deserts formed/located where they are?

1. high pressure - deserts are found at 30 degrees latitude because air sinks, creating dry conditions

2. sinking air prevents clouds from forming and there is very little evaporation, so there is very little rainfall

why are rainforests formed/located where they are?

1. low pressure - rainforests are found at the equator (0 degrees latitude) where warm air rises

2. rising air creates clouds leading to daily heavy rainfall

3. the equator gets direct sunlight all year, creating hot, humid conditions

how is climate change affecting tropical storms

1. becoming stronger with higher windspeeds, more rainfall

2. longer seasons - tropical storms forming earlier in the year

3. number of storms are slowly increasing