The Scientific Basis for the Successful Forecast of the Heavy Torrential and Flood over the Mid-Lower Reaches of the Yangtze River in 1998
Chen Juying (1)
(1) Chinese Academy of Meteorological Sciences, Beijing 100081,CHINA
China is a big country with a complex climate, the climatic change will be different in different locations and in different season of year, the floods/droughts of flood season(JJA) is the most frequent. The spatial and temporal collective intensity of the heavy torrential rain and flood over the mid - lower reaches of the Yangtze River in 1998, it is the most severe during 20th century, but it was accuracy forecasted by us with physical statistical methods and forecast model in March, we have obtained best and successful long-range forecasting of heavy flood in 1998(to see fig.4). Severe Floods as a results of extreme precipitation events of climate system, it is the events of small probability and it's forecast is hard difficult, long term effected factors of flood is very complexity, such as, previous state of ENSO(it shows in fig.1), atmospheric circulation characteristics, precipitation, temperature and astronomical factors etc., therefore, it requisites for make full investigations to predictors previous to develop prediction model of heavy floods, to seek high correlation predictors of heavy floods ,on these basis , to analysis ensemble for these high correlation multi-factors and developing the forecast model of floods(as shown in fig.2 and fig.3 etc). In this paper, some high correlation predictors and forecasting models are introduced, these predictors and forecasting models play an important role in successful long-range forecasting of more flood events(such as floods of 1991,1995,1996 and 1998). Another, the medium-range forecasts of the heavy torrential rain in last ten-day of 1998 in the mid-lower reaches of the Yangtze River that was accurate forecasted too.
