Exploring temporal and spatial variability of precipitation of Weizhou Island, South China Sea

Abstract

Abstract Study region Weizhou Island, Northern part of the South China Sea. Study focus Research on precipitation variability is important for understanding the water cycle and to evaluate risk of flood and drought risks. We studied precipitation variability, including amounts and intensity, on a sea island (Weizhou Island) using a long time-series daily precipitation dataset. An innovative trend test (Sen trend test) and M-K trend test were used to analyze trends of rainfall variability. The Concentration Index (CI1) and the precipitation concentration index (CI2) were used, respectively, to evaluate the intensity and seasonality of rainfall. The continuous wavelet transform (CWT) was used to analyze CI1 and CI2. NCEP/NCAR data were used to determine if large scale circulation has an influence on Weizhou Island rainfall variability. New hydrological insights: (1) Rainfall amounts had a non-homogeneous temporal distribution during periods of 1961–1990, 1981–2010 and 1961–2010 on Weizhou Island. (2) Large scale atmospheric circulation may be the major atmospheric driving force of precipitation changes. (3) Precipitation has a cyclical nature on Weizhou Island. (4) Precipitation pattern on Weizhou Island is also affected by oceanic climate. The results provide a scientific basis for water resource management on Weizhou Island.