Spatial-Temporal Characteristics of Rainstorm and Its Relationship with Flood in the Three Gorges Reservoir
The three gorges area was located in the connection of the Sichuan Basin and the Middle-Lower Yangtze plains. It crossed the canyon of central Hubei and ridge-valley of eastern Sichuan, facing the south of the Daba Mountain and the north of the Sichuan-Hubei plateau. Under the influences of East Asian summer monsoon and its special topography, it often has heavy rainstorm and flood which has an important influence on waterways safety and flood control. Many domestic researchers have made extensive studies, such as water resources, ecological environment, and extreme events of weather and climate in the three gorges area. Some researchers performed weather analysis of heavy rainstorm in the three gorges area, but they mainly focused on case studies of heavy rainstorm, drought-flood characteristics in summer, and circulation background of precipitation anomaly. Studies on long-term variability of heavy rainstorm in the three gorges area do not seem adequate. Based on daily precipitation data at 35 stations in or around the Three Gorges Reservoir during the period 1961-2010, the dynamic temporal and spatial variation characteristics of rainstorm days and its intensity were analyzed by mathematical statistical methods. Results show that the mean annual rainstorm days were 3.4 days, oscillating with a cycle of about 2.3 or 5 years, and the rainstorm intensity was 72.9 mm, oscillating with a cycle of about 9.6 years in the past 50 years. The frequency and intensity of rainstorm in July were the most in the year. Both the mean annual rainstorm days and intensity were positive anomaly in the 1980s, and in the first 10 years of the 21st century, rainstorm days obviously decreased, but the intensity increased. The distribution of rainstorm days of the mountainous region seemed to be more than that of the valleys and basins region. The southeastern Three Gorges Reservoir had the most rainstorm days and the continuous rainstorm here was most frequent. Results also show that there was a close relationship between heavy rain and flooding disasters in the monsoon region, especially in the Three Gorges Reservoir in the 1980s. It should also be noted that with storing water of the Three Gorges, the increasing water level and surface of it might have some influence on local climate. Now, although some exploratory studies have been done, most of them appear to be fall short of revealing the influence of the Three Gorges on local climate well due to the lack of observation data. This needs long-term observation and study.
Three Gorges ReservoirRainstormInterdecadal variation
NETL
NSTL
万方数据
维普
