The reasons for the seasons — what do we need to know about seasonal change?

“The only constant thing is change,” a popular line goes — and for the Philippines, change is indeed around the corner, as far as our seasons are concerned.

We have been accustomed to the usual warm and sticky feel during the hot dry season, but the good news is that we are about to see a respite in the coming days as the rains finally set in. Whew! Have you ever wondered what causes these changes in the seasons, especially in the Philippines? Here are some reasons why we experience a changing of seasons:

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Pressure zones. There are two major factors that influence the change in seasons globally: the High Pressure Area (HPA), which comes from colder regions, and the Low Pressure Area (LPA), which mostly propagates in warmer regions. In the Philippines, these gigantic pressure zones are crucial in determining our tropical climate. Just recently, we have been witnessing the formation of multiple LPAs from the tropical Pacific, and the advance of the Intertropical Convergence Zone (ITCZ). This drives the buildup of local thunderstorms, bringing rain showers and occasional floods in places.

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Monsoon. The monsoon is a seasonal rain and wind pattern that occurs over South Asia, among other places. This wind system transports heat from more moist regions, driving rainfall distribution over land, which in turn regulates temperature and brings back the greenery to vast tracts of land.

A large portion of of our global population relies heavily on monsoon rains for domestic and economic purposes. Monsoon rains provide water to agriculture and to other industries essential for economic growth.

Today, water has become a big challenge globally due to lack of supply. As nations continue to face unprecedented population growth, the more pressure is placed on our global water supply. This is where monsoons become relevant as it i is one natural force that is capable of replenishing water reservoirs that sustain human activities like agriculture. A disruption to its natural cycle would mean a disaster to both agriculture and the economy as well.

 

 

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Tropical cyclone. Based on recent studies, the annual tropical cyclone formation cycle drives monsoon rains stronger along the Western shores of the Philippines. With the advance of the Southwest Monsoon (Habagat) during mid-June through late August, the prevalence of tropical cyclones we call “bagyo” would definitely guarantee a steady stream of warm and most air masses — thus the incessant buildup of rain-bearing clouds toward the West Philippine Sea, and the all-too-familiar severe flooding we have come to dread.

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As an archipelagic region, the Philippines is known for the vagaries in its weather conditions. Hence, we should regularly check the forecast and weather observations through the help of weather applications, such as the WeatherPhilippines mobile app. This will enable us to maximize knowledge and moving forward, build a #WeatherWiser nation that we are aiming to achieve.

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Written by: Adonis S. Manzan, Typhoon Specialist, WeatherPhilippines Foundation, Inc.

©2019 WeatherPhilippines Foundation

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