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1. Topic analysis
If more effective control measures are not taken, the main statistical data of the past 10 years will be used to predict and analyze the future development trend of water pollution in the Yangtze River, such as studying the situation in the next 10 years.
Attachment 4 provides the main statistical data on the water quality of the Yangtze River in the past ten years, and it is necessary to predict the development trend of the Yangtze River water pollution in the next ten years based on the data of this decade.
Can pass the hydrological year (Hydrological year refers to the average of all monitoring data in a year) Research on the changes of water quality in the whole basin to predict and analyze the future development trend of water pollution in the Yangtze River.
The water quality problem of the Yangtze River is a complex non-linear system, with few data samples, uncertain changes in the law, and a long time for prediction, which conforms to the grey prediction theory., That is, using less known data to predict the unknown process that changes within a certain range and is related to the time series, so the gray prediction model is used to predict the water quality in the next 10 years.
2. Principle steps
The prediction principle of the GM(1,1) model is to generate a set of new data sequences with obvious trends in a cumulative manner for a certain data sequence, establish a model for prediction according to the growth trend of the new data sequence, and then use the cumulative reduction The method performs reverse calculation, restores the original data sequence, and obtains the prediction result.
Hydrology