Xihui Gu

Nonstationarity-based evaluation of flood risk in the Pearl River basin: changing patterns, causes and implications

ABSTRACT Nonstationary GEV-CDN models considering time as a covariate are built for evaluating the flood risk and failure risk of the major flood-control infrastructure in the Pearl River basin, China. The results indicate: (1) increasing peak flood flow is observed in the mainstream of the West River and North River basins and decreasing peak flood flow is observed in the East River basin; in particular, increasing peak flood flow is detected in the mainstream of the lower Pearl River basin and also in the Pearl River Delta region, the most densely populated region of the Pearl River basin; (2) differences in return periods analysed under stationarity and nonstationarity assumptions are found mainly for floods with return periods longer than 50 years; and (3) the failure risks of flood-control infrastructure based on failure risk analysis are higher under the nonstationarity assumption than under the stationarity assumption. The flood-control infrastructure is at higher risk of flood and failure under the influence of climate change and human activities in the middle and lower parts of Pearl River basin. EDITOR D. Koutsoyiannis ASSOCIATE EDITOR G. Thirel

Nonstationarity and clustering of flood characteristics and relations with the climate indices in the Poyang Lake basin, China

ABSTRACT The magnitude, occurrence rate and occurrence timing of floods in the Poyang Lake basin were analysed. The flood series were acquired by annual and seasonal maximum flow (AMF) sampling and peaks-over-threshold (POT) sampling. Nonstationarity and uncertainty were analysed using kernel density estimation and the bootstrap resampling methods. Using the relationships between flood indices and climate indices, i.e. El Niño/Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Indian Ocean Dipole (IOD) and Pacific Decadal Oscillation (PDO), the potential causes of flooding were investigated. The results indicate that (1) the magnitudes of annual and seasonal AMF- and POT-based sampled floods generally exhibit an increasing tendency; (2) the highest occurrence rates of floods identified were during the 1990s, when the flood-affected crop area, flood-damaged crop area and crop failure area reached the highest levels; and (3) ENSO and IOD are the major climate indices that significantly correlate with the magnitude and frequency of floods of the following year. EDITOR A. Castellarin ASSOCIATE EDITOR T. Kjeldsen

The impact of tropical cyclones on extreme precipitation over coastal and inland areas of China and its association to the ENSO

AbstractThe coastal part of China and its surrounding regions are dominated by highly-dense population and highly-developed economy. Extreme precipitation events (EPEs) cause a lot of damage and hence, changes in these events and their causes have been drawing considerable attention. This study investigated EPEs resulting from Western North Pacific (WNP) Tropical Cyclones (TCs) and their potential link to El Nino-Southern Oscillation (ENSO), using TC track data, daily precipitation data from 2313 stations for 1951-2014, and NCAR/NCEP reanalysis dataset. Two types of EPEs were considered: EPEs within 500 km from the TC center; and those caused by the mesoscale and synoptic system called as the Predecessor Rain Events (PREs) beyond 1000 km from the TC center. Results indicated significant impacts of TCs on EPEs along the coastal areas, and discernable effects in inland areas of China. However, the effect of TCs on EPEs tended to be modulated by ENSO. During neutral years, inland areas of China are more affe...