The standardized index mode of the index whose value decreases with the increase of interference is as follows
pij = Oij/si95× 100(8- 1)
Where: Pij and Oij—— are the standardized index and original observation value of I index at the j-th sampling point, respectively;
Si95 is the standardized threshold of the I-th indicator, and the original observation value of the I-th indicator in the 95th percentile of all sampling points is taken;
i= 1，2，…，m； j= 1，2，…，n .
The standardized index mode of the index whose value increases with the increase of interference is as follows
pij =(maxOi-Oij)/(maxOi-Si5)× 100(8-2)
Where: maxoi——n the maximum value of the i-th index in n sampling points;
Si5—— the standardized threshold of the I-th indicator, and the original observation value of the I-th indicator in the 5th percentile of all sampling points is taken.
2. Ecological health comprehensive index model
The comprehensive index value of ecological health at the sampling point is the average of the standardized indexes of each index at that point. The comprehensive index model of ecological health is
Efficient utilization of water resources and ecological restoration technology of estuary and coast in seawater intrusion area of Jiaodong Peninsula
Where: Ij—— comprehensive index of ecological health at the j-th sampling point.