基于灰色马尔科夫模型的南四湖水质预测

Water quality prediction of Nansi Lake based on grey Markov model

针对传统GM(1,1)模型存在灰色偏差和抗干扰能力弱的问题,建立一种等维新息灰色马尔科夫模型。该模型采用灰色马尔科夫模型改进传统GM(1,1)模型,再利用等维新息思想更新建模所需数据序列。运用该模型对南四湖2019—2021年的水质状况和水质演变趋势进行预测,结果表明:灰色马尔科夫模型的相对误差小、精度高、预测结果合理;2019—2021年南四湖水质整体呈现由北向南逐渐变好的趋势,其中COD_(Cr)、NH_(3)-N、COD_(Mn)质量浓度呈下降趋势,TP、TN质量浓度有上升现象,存在超标风险,应加强对南四湖流域TP、TN的控制。

Aiming at the problems of grey deviation and weak anti-interference ability of the traditional GM(1,1)model,a grey Markov model with equal dimension and new information was established.The model adopted grey Markov model to improve the traditional GM(1,1)model and then used the concept of equal dimension and new information to update the data sequence required for modeling.The model was used to predict the water quality status and water quality evolution trend of Nansi Lake from 2019 to 2021.The results show that the grey Markov water quality model has small relative errors,high accuracy and reasonable prediction results.From 2019 to 2021,the overall water quality of Nansi Lake will gradually improve from north to south,wherein the mass concentration of COD_(Cr),NH_(3)-N,and COD_(Mn)shows a downward trend while the mass concentration of TP and TN has an upward trend and there is a risk of exceeding the standard.Therefore,the control of TP and TN in the Nansi Lake Basin should be strengthened.