Amihan and Habagat

ITCZ and monsoons

By Restie Carullo

ITCZ (Inter-Tropical Convergence Zone)​

You often hear the ITCZ on weather reports. Known to sailors as doldrums, the ITCZ is where trade winds from the Northern Hemisphere and Southern Hemisphere converge or meet.

ITCZ (Inter-Tropical Convergence Zone)​

The ITCZ affects the Philippines from May to October. From November to April, it is located south of the Philippines. With the change of seasons, the zone of convergence moves back and forth across the equator. In the ITCZ, the air moves in vertical motion. This provides moderate to strong surface winds and frequent cloudiness, rain and thunderstorm.​

​It plays an important role in the formation of tropical cyclone (bagyo).

Multiple Choice

ITCZ is caused by meeting of westerlies from both Northern and Southern Hemispheres.

• True

• False

monsoons

Monsoons are winds that change direction​ as seasonal changes. Wind blows in one direction for about six months, then blows the other way for the next six months.

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Monsoons are caused by the difference between the annual temperature trends over land and sea.​

Monsoons

​During the winter months in the Northern Hemisphere, the continents are much cooler than the sea. The air pressure over the continents is higher than the air pressure over the sea. Dry air flows from the high pressure area over the continent to the low pressure area over the sea.

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During summer​, this pattern is reversed as the continent becomes much warmer than the sea.

Monsoons

Monsoons

​Northeast Monsoon, brings cooler and drier air from the North East during the period when it is winter in the Northern Hemisphere. It is characterized by widespread cloudiness with rains and rain showers.

​Amihan

Monsoons

​Southwest Monsoon, brings hotter and more humid weather. This also occasionally intensify the typhoons as it brings more moisture leading to more rain. It is driven by the prevailing wind that is coming from west or southwest.

​Habagat

Multiple Choice

To understand the monsoon is to think of it as large-scale sea breeze and land breeze system.

• True

• False