Evaluating the Increasing Trend of Strength and Severe Wind Hazard of Philippine Typhoons Using the Holland-B parameter and Regional Cyclonic Wind Field Modeling

Abstract

For the Philippines, a country exposed to multiple natural hazards like severe wind, sustainable development includes resiliency. Severe wind hazard is brought by tropical cyclones in the Western Pacific, known as typhoons, that frequent the Philippines. Therefore, adequately evaluating the wind hazard and its impact is crucial for sustainable building design. Acknowledging the impacts of climate change on said hazards would require adaptation to its consequences which necessitate a deeper understanding on the changing behavior of typhoons in recent years. For this study, detailed wind information from the Japan Meteorological Agency from 1977-2021, the Holland-B parameter, and the radius of maximum wind speed for each typhoon, are determined for simulation of the regional cyclonic wind field. The analysis of the Holland-B parameters, which represent the steepness of the pressure gradient and tropical cyclone convection, suggest that the Holland-B parameters have been increasing since 2011. The regional wind fields caused by the typhoons also suggest an increasing trend in severe wind hazard. Seasonality for the location of severe wind hazard is also observed, with the Southern Philippines experiencing an increase (decrease) during the Northeast (Southwest) Monsoon season, and the Northern Philippines experiencing an increase (decrease) during the Southwest (Northeast) Monsoon season.

Evaluating the Increasing Trend of Strength and Severe Wind Hazard of Philippine Typhoons Using the Holland-B Parameter and Regional Cyclonic Wind Field Modeling

“…The gradient wind, free from surface friction and turbulent effects, is often less than the surface winds. Wind profiles were determined to be closer in value to the sustained winds, such as in the case of Typhoon Haiyan in 2013 [40], Haima in 2016 [41], and Goni in 2020 [42]. Conversion factors are also introduced to relate the gradient wind to the surface wind [43,44].…”

“…With the change in characteristics and behavior of typhoons due to climate change identified, the evaluation of the trend of severe wind hazards that typhoons are causing in the Philippines remains. This study aims to identify the changes in the wind hazard of typhoons in the Philippines by evaluating the changes in the regional cyclonic wind fields [20] within the Philippine Area of Responsibility. Identifying these changes in the wind hazard could prompt policy-makers and engineers to reconfigure their building design and disaster risk reduction and management measures to ensure sustainability that adapts to climate change.…”