Long-term change of tropical cyclones activity and its potential impacts on Vietnam

Abstract

Vietnam has been considered as one of the countries most affected by climate change. Over the past several years, frequency and intensity of tropical cyclones landed Vietnam have been increasing resulting in socio-economic damages and negative impacts on the environment. Previous studies have examined tropical cyclones activity over the South China Sea, but most of those concerned about the tropical cyclones originated within this ocean while the others from the Philippines Sea with strong intensity have been received little attention as well as their role to the climatic variation. Here, we would like to explore: 1. The long-term change of tropical cyclones activity in the South China Sea and those immigrates from the Philippines Sea over the period time 1977-2016. 2. The potential impacts of these tropical cyclones to Vietnam through an insight view of the Power Dissipation Index and the rainfall associated with tropical cyclones and the tropical depressions. In this study, using several observation datasets and the statistical technique of linear regression analysis, it reveals that, the tropical cyclones activity have not changed apparently in frequency and intensity for 40 years (1977-2016). In terms of the rainfall amount, there is an increasing trend in the whole of Vietnam. However, while the North of Vietnam shows an increasing dramatically in the rainfall amount, rainfall days as well as the rainfall ratio caused by tropical cyclones and tropical depressions, the Central and South do not show any significant change. Consequently, this study suggests that in addition to the annual number of tropical cyclones, those rainfall events associated with them should be concerned and included in the preparedness and response plans both in regional and national scale.