Study On Change Of Water Area In Huanren Based On Landsat Data And The Relationship With The Climate

Water is an important resource,to grasp the changes in water resources,and use these information it is of great significance to the effective use of water resources and the rational planning of water resources.Huanren is a water conservation area in northeast Liaoning Province.It is rich in water resources.The research on the relationship between the change of water area and the climate factors in Huanren area has certain significance for the rational development and utilization of water resources in the future to ensure the sustainable utilization of water resources in Huanren.In this paper,the final consideration of the multi-faceted elements is the TM image data and OLI image data of the Landsat satellite from 2000 to 2015 of Huanren.Using ENVI software to data radiation calibration,atmospheric correction and cropped data preprocessing.Comparison of single-band threshold method,CART-based decision tree classification,NDWI and MNDWI,final selection of a more convenient,more cost-effective,more accurate MNDWI model to extract water area.Using ArcGIS Software to count Water Area.According to the result of extraction,analysis of interannual and dynamic changes.Analysis of linear relationships and correlations of four climate factors combined with temperature,rainfall,evaporation,and relative humidity.Establish a fitting model of water area and climatic factors,provide a reference for forecasting changes in the area of water in Huanren.The main research conclusions obtained in this paper are as follows:(1)Through the analysis of the water area obtained,the water area in Huanren from2000 to 2015 more volatile,trendline slope is negative,overall decline.The fastest growing period is 2003-2004,the dynamic degree is 11.216;The fastest time to reduce the area is2001-2002,dynamic degree is-8.657.(2)The average daily temperature in the flood season of Huanren region declined from2015 to 2000,the linear cooling rate is-0.357?/10a.The decline trend of daily evaporation,the linear tendency is-0.058 mm/10a.The daily rainfall is on the rise,and its tendency rate is0.61mm/10a.The average daily relative humidity is on the rise,and the linear tendency is0.731%/10a.After analyzing the linear relationship between water area and climatic factors,get a conclusion:water area is positively correlated with temperature,rainfall,and relative humidity,the slopes of the trend lines are 1.907,3.726 and 2.976.Negative correlation with evaporation,the slope of the trend line is-1.061.(3)Through the analysis of the correlation between water area and climatic factors,we reached a conclusion:the correlation between rainfall and water area is the highest,the Pearson coefficient is 0.918,pass the test with a confidence of 0.01;Pearson coefficient of daily mean relative humidity and water area is 0.736,pass the test with a confidence of 0.05;Daily evap-oration and daily mean air temperature don't pass the significance level test.The degree of correlation between climatic factors and water area from large to smal is ranked as follows:Rainfall>Relative humidity>Temperature>Evaporation.Grey correlation analysis of water area and climatic factors,The correlation coefficients between daily rainfall,daily evaporation,daily mean temperature,daily mean relative humidity and water area are as follows:0.8295?0.6722?0.6812?0.7072.The order of correlation between climatic factors and water area is as follows:Rainfall>Relative humidity>Temperature>Evaporation.So rainfall is the most important factor affecting the change of water area in Huanren.(4)This paper establishes apolynomial fitting model between water area and daily rainfall.The R~2 is 0.8703.The polynomial fitting model has the highest correlation coefficient.A comprehensive model for the integration of the four climatic factors:water area and daily average temperature,daily rainfall,daily evaporation,and daily average relative humidity has been established.R~2 is 0.921,Sig is 0.006<0.05.Good model and data fitting.The resulting model plays a role in predicting the changing trend of water area.