Research on spatiotemporal changes of water level corresponding to different flood frequency to ENSO in the Pearl River Delta

摘要

Based on Annual Maximum Water Level (AMWL) datasets extracted from 34 gauging stations in the Pearl River Delta (PRD) and the OceanicNino Index (ONI) data in the Nino 3.4 region of 1951-2008, the GEV distribution was used to get the frequency analysis. The water level variation calculated from series of pre-1980 and post-1980 was examined to comprehensively understand flood frequency characteristics. The interdecadal variation in the response of flood level to ENSO in the past fifty years was researched by moving correlation. The spatial maps for flood levels corresponding to different return periods suggest the water level increases gradually from the coast to the riverine system. The flood level increments of different return periods in all sites are obvious. The water levels show a decreasing trend the upper PRD while there is an increasing trend in the middle and lower PRD. The long-term variation of interannual relationship between ENSO and flood level has a significant stage characteristic and it has a great change in the 1980s. The flood level has various responses to various seasonal ENSO.