气候变化领域集成服务门户

Measured streamflow and flood series of 43 gauging stations from 25 west flowing rivers in Kerala, India, were analysed for their descriptive characteristics to study their spatial and temporal variation. The spatial and temporal variations in streamflow are influenced by many factors including climatic and basin characteristics. Streamflow data from each station (length varies from 14 to 43years) is analysed for their internal characteristics such as trend, stationarity, homogeneity, noise and periodicity to incorporate it in hydrological models, so that their predictions would be more accurate. The internal characteristics were studied along with the statistical analysis. For analysing each internal characteristic, more than one method of analysis has been used to have reliable result. The trend characteristic was analysed using Mann-Kendall (MK) test, Sen's slope test, Spearman's rank correlation coefficient and Pearson correlation coefficient methods. Stationarity characteristics have been tested using augmented Dickey-Fuller test (ADF), Phillips-Perron test and Kwiatkowski-Phillips-Schmidt-Shin (KPSS) test. For identifying homogeneous nature, Pettitt test, standard normal homogeneity (SNH) test, Buishand test and von Neumann tests were used. Noise in the streamflow was verified using Box-Peirce, Ljung-Box and McLeod-Li tests. From the study, it is found that the daily series is non-homogeneous, stationary data with white noise, whereas flood series shows mixed characteristics. Based on the variations in the time series, the daily streamflow and flood series are classified into different categories such as high, average, moderate, minor and no variation stations. In most of the river basins, daily flow shows average variation. Flood series shows average variation in 44% of stations and moderate variation in 28% of stations.