Đánh giá xu hướng biến động mưa trên lưu vực sông Cả giai đoạn 1959 - 2016 sử dụng số liệu thực đo

Abstract

This paper presents assessment results of variable trends of monthly, season and annual rainfall in Ca river basin in the period from 1959 to 2018 using rainfall data at 8 stations, statistical analysis and non-parametric Mann-Kendall test. The results show that monthly rainfall tends to decrease -0.06 to -3.21 mm/month in the upper and downstream regions, from -0.01 to -1.15 mm/month in the middle region of river basin. A decrease of rainfall occurred not only in dry season (from May to November) but also in June of the wet season. Monthly rainfall tends to increase up to 3.80 mm/month in July. At Do Luong and Quy Chau stations, season rainfall (both dry and wet seasons) increases from 0.26 to 5.26 mm/season for wet season and from 0.08 to 0.43 mm/season for the dry season. At remain stations, season rainfall decreases significantly up to 3.4 mm/season for the dry season and -1.9 mm/season for the wet season. The annual rainfall declines greatly in a range between -2.2 and -3.7 mm/year at Muong Xen, Con Cuong, Son Diem, Hoa Duyet and Quy Hop, while at Tuong Duong, Do Luong and Quy Chau, its’ value rises up to 6.2 mm/year.