Analysis of spatial dependence of water level in river network area of Pearl River Delta based on pair-copula construction

Based on the monthly mean water level data of 15 hydrological stations in river network area of the Pearl River Delta from 1957 to 2016, a water level spatial dependence model was established using the pair-copula construction to generate samples, and the F-madogram method was used to quantitatively evaluate the spatial dependence of water level in river network area of the Pearl River Delta in different stages and distance ranges at different time scales. The results show that the spatial dependence of water level in the area with river network developing in the transverse direction is weaker than that in the 45° southeast direction in river network area of the Pearl River Delta, the spatial dependence of water level in wet season is significantly stronger than that in dry season, and the spatial dependence of water level at seasonal scale is weaker than that at annual scale. Due to the influence of human activities, the spatial dependence of water level in wet season from 1987 to 2016 was significantly enhanced compared with that in the period of 1957 to 1986 in a large distance range. In a small distance range, the spatial dependence of annual minimum monthly water level from 1987 to 2016 was significantly weaker than that in the period of 1957 to 1986, and the spatial dependence of annual maximum monthly water level from 1987 to 2016 was significantly enhanced compared with that in the period of 1957 to 1986.