Results show that, according to the linear regression analysis, regional annual rainfall is not much fluctuated, the rainy season and annual rainfall tend to decrease, while rainfall in the dry season tends to increase. According to Sen’s slope chart, July rain gains highest increasement, while that of August tends to decrease most. In general, the precipitation concentration index revealed the presence of a high and very high concentration of rainfall. | VNU Journal of Science Earth and Environmental Sciences Vol. 37 No. 4 2021 22-32 Original Article Trend Analysis of Rainfall in the Phu Quoc Island Nguyen Quang Hung1 Le Xuan Hien2 1 VNU University of Science 334 Nguyen Trai Thanh Xuan Hanoi Vietnam 2 Kien Giang provincial Meteo-Hydrological Center 01 Nguyen Van Kien Vinh Thanh Rach Gia Kien Giang Vietnam Received 15 September 2020 Revised 25 Janurary 2021 Accepted 29 Janurary 2021 Abstract Assess the trend of rainfall change in Phu Quoc island is an interesting topic which establishes a scientific basis for rainfall forecast trends as well as regional development planning. Rainfall measurement data from 1985 to 2018 was used to analyse with different methods included Sen s slope linear regression Mann-Kendall MK test CV coefficient Coefficient of Variation PCI Precipitation Concentration Index examine drought level over time by using SPI - standardized rainfall index. Results show that according to the linear regression analysis regional annual rainfall is not much fluctuated the rainy season and annual rainfall tend to decrease while rainfall in the dry season tends to increase. According to Sen s slope chart July rain gains highest increasement while that of August tends to decrease most. In general the precipitation concentration index revealed the presence of a high and very high concentration of rainfall. Keyword MK test Sen s slope Phu Quoc daily rainfall. _ Corresponding author. E-mail address nguyenquanghung@ https 2588-1094 22 N. Q Hung L. X. Hien VNU Journal of Science Earth and Environmental Sciences Vol. 37 No. 4 2021 22-32 23 Đánh giá xu thế biến đổi của lượng mưa tại đảo Phú Quốc Nguyễn Quang Hưng1 Lê Xuân Hiền2 Trường Đại học Khoa học Tự nhiên Đại học Quốc gia Hà Nội 1 334 Nguyễn Trãi Thanh Xuân Hà Nội Việt Nam 2 Đài Khí tượng Thủy văn tỉnh Kiên Giang 01 Nguyễn Văn Kiến Vĩnh Thanh Rạch Giá Kiên Giang Việt Nam Nhận ngày 16 tháng 9 năm 2020 Chỉnh sửa ngày 25 .
