The frequency distribution of wind speeds and directions (a) from Jan 2000 to Dec 2006, (b) from Jan 2007 to Dec 2016 and (c) the biplot of environmental variables pre-shift and post-shift at Lake Taihu. The length of the arrow lines represents the variance. The black and green dots represent a partition of time series into two groups with circles representing 95% confidence of interval for each group. The positive and negative correlations of Environmental variables are presented in positive and negative quadrants of biplot.