Comparative Analysis Of GF-1 And HJ-1 Data To Derive The Optimal Scale For Monitoring Heavy Metal Stress In Rice

Soil heavy metal pollution is one of the major problems in the field of environmental protection,and heavy metal pollution of crops casued by it is also needed to be solved urgently.Therefore,it is very necessary to accurately and timely monitor heavy metal pollution.Remote sensing as an effective tool to monitor the level of heavy metal pollution in crops can realize large-scale real-time monitoring.However,with the increase of satellites,there are more and more remote sensing data at various scales.The optimal scale for monitoring heavy metal stress in crops is still unknown.The research centered on the development of heavy metal stress in rice.In order to select the optimal scale,using the methods of ratio analysis and statistical analysis to compare the heavy metal stress in rice under different spatial scales,and determine the optimal scale of heavy metal stress.The selected test sites are situated in Zhuzhou,which is located in the east of Hunan Province,China.Two paddy fields with different levels of heavy metal pollution are selected for comparison;the leaf area index(LAI)and meteorological data during the period of rice growth are obtained.At the same time,the 2 m,8 m,and 16 m resolution GF-1(China)data and the 30 m resolution HJ-1(China)data are obtained,too.Through the combination of remote sensing data and crop growth model(World Food Studies,WOFOST),we also conducted data processing and analysis,and then we explored the optimal scale of remote sensing for monitoring rice heavy metals.The research work and main conclusions of this study are as follows:(1)Heavy metal stress will inevitably cause changes in rice physiological parameters,and it is very important to select sensitive indicators for monitoring heavy metal stress in rice.In order to accurately assess the heavy metal stress,a new index of heavy metal stress monitoring has been established,that is,the mass ratio of rice storage organs and roots(SORMR),and determine the effectiveness of the SORMR;we conclude that SORMR can effectively monitor heavy metal stress in rice.(2)By comparing and analyzing the observation results of remote sensing data with the 2 m,8 m,and 16 m resolution GF-1(China)data and the 30 m resolution HJ-1(China)data,we combined with the dry weight of roots(WRT),dry weight of storage organs(WSO)and mass ratio SORMR to determine the appropriate scale and optimal scale for heavy metal stress monitoring in rice.(3)Through the above experiments,we found that different degrees of spatial resolution showed different degrees of heavy metal stress,and the 8m and 16 m images of GF-1 were suitable for monitoring heavy metal stress in rice,that is,both 8m and 16 m were the appropriate scale for heavy metal stress monitoring in rice.16 m was considered the optimal scale to assess heavy metal stress in rice.