Applying the Mann-Kendall method to test the change trend of rainfall and temperature in Bac Lieu province 1980-2022

Abstract

In this study, the Mann-Kendall method and linear regression analysis were used to assess trends in rainfall and temperature changes in Bac Lieu province, based on daily data from the Bac Lieu meteorological station and four additional rainfall stations (Bac Lieu, Phuoc Long, Ganh Hao, and Dong Hai). The results indicated a statistically significant increasing trend in temperature, including daily average, maximum, and minimum temperatures, at the 95% confidence level. Specifically, the average daily temperature rose by approximately 0.03°C per year, the maximum temperature increased by 0.02°C per year, and the minimum temperature increased by 0.0306°C per year. This trend resulted in a narrowing gap between maximum and minimum temperatures, leading to longer periods of warmer nights. Rainfall also showed an increasing trend at all four stations. At Bac Lieu, Phuoc Long, and Dong Hai stations, rainfall increased by about 7.5 mm/year, 11.5 mm/year, and 12.8 mm/year, respectively, with statistical significance at the 95% confidence level. However, the rainfall trend at Ganh Hao station was not statistically significant. Additionally, the linear regression analysis indicated a greater rate of increase in rainfall compared to the Sen trend analysis.