06. Monsoons

Demo on how wind is deflected to the right in the northern hemisphere due to the Coriolis effect from our Earth rotation.

Monsoon winds are regional wind patterns that reverse direction seasonally due to the Coriolis Effect produced by the rotation of the earth. The Coriolis Effect cause the wind to be deflected. In the northern hemisphere, the wind is deflected to the right and to the left in the southern hemisphere.

Between June and September, the northern hemisphere experience summer and the air over Central Asia heats up, expands and rises, forming a region of low pressure over the area. The southern hemisphere experience winter and the low temperature cause the air to be cold and dense, resulting an area of high pressure over Australia. Air from Australia moves towards Central Asia as the southeast monsoon due to the difference in pressure between Central Asia and Australia. As the wind cross the Equator, the Coriolis Effect deflects the wind to the right and it became the southwest monsoon.

Between October and February, the southern hemisphere experience summer and an area of low pressure forms over Australia. The northern hemisphere experience winter and the low temperature causes the air to be cold and dense, resulting an area of high pressure over Central Asia. Air from Central Asia moves towards Australia due to the difference in pressure between Central Asia and Australia. The Coriolis effect deflects the wind to the right in the northern hemisphere thus it moves towards the equator as the Northeast monsoon. When the wind crosses the equator, the Coriolis effect deflects the wind to the left in the southern hemisphere and became the northwest monsoon.

Watch the video below showing how the SE Monsoon affects India in June, 2013.

1. How does Monsoon wind develop?

2. Why does the SE Monsoon bring heavy rain to India?

3. What are the impacts of the heavy rain?

Watch the video below showing how the NE Monsoon affects Malaysia in Dec 2014.

1. How does Monsoon wind develop?

2. Why does the NE Monsoon bring heavy rain to Malaysia?

3. What are the impacts of the heavy rain?