The burning of crop residues in fields is a significant global biomass burning activity which is a key element of the terrestrial carbon cycle,and an important source of atmospheric trace gasses and aerosols.Accurate ...The burning of crop residues in fields is a significant global biomass burning activity which is a key element of the terrestrial carbon cycle,and an important source of atmospheric trace gasses and aerosols.Accurate estimation of cropland burned area is both crucial and challenging,especially for the small and fragmented burned scars in China.Here we developed an automated burned area mapping algorithm that was implemented using Sentinel-2 Multi Spectral Instrument(MSI)data and its effectiveness was tested taking Songnen Plain,Northeast China as a case using satellite image of 2020.We employed a logistic regression method for integrating multiple spectral data into a synthetic indicator,and compared the results with manually interpreted burned area reference maps and the Moderate-Resolution Imaging Spectroradiometer(MODIS)MCD64A1 burned area product.The overall accuracy of the single variable logistic regression was 77.38%to 86.90%and 73.47%to 97.14%for the 52TCQ and 51TYM cases,respectively.In comparison,the accuracy of the burned area map was improved to 87.14%and 98.33%for the 52TCQ and 51TYM cases,respectively by multiple variable logistic regression of Sentind-2 images.The balance of omission error and commission error was also improved.The integration of multiple spectral data combined with a logistic regression method proves to be effective for burned area detection,offering a highly automated process with an automatic threshold determination mechanism.This method exhibits excellent extensibility and flexibility taking the image tile as the operating unit.It is suitable for burned area detection at a regional scale and can also be implemented with other satellite data.展开更多
After the occurrence of an earthquake,strong motion observation networks can record ground motion at distributed observation stations. Based on the ground motion parameters from these records,the spatial distribution ...After the occurrence of an earthquake,strong motion observation networks can record ground motion at distributed observation stations. Based on the ground motion parameters from these records,the spatial distribution of seismic intensity can be quickly determined,and the degree of damage in different areas can be estimated. This information provides the technical basis for the emergency response,so as to ensure that rescue teams can reach extreme earthquake areas and carry out the search and rescue operation in an accurate and timely manner to reduce casualties and property loss. In this paper,we introduced 7 intensity algorithms and compared the results with the records of the Jiuzhaigou M_S7. 0 earthquake. We found that the differences between the instrumental intensities calculated by each method and the macro intensities were within a 1-degree range,which suggested good practicality of these different methods. The results calculated by the industrial standards-based calculation method and the integrated test showed good consistency.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.42101414)Natural Science Found for Outstanding Young Scholars in Jilin Province(No.20230508106RC)。
文摘The burning of crop residues in fields is a significant global biomass burning activity which is a key element of the terrestrial carbon cycle,and an important source of atmospheric trace gasses and aerosols.Accurate estimation of cropland burned area is both crucial and challenging,especially for the small and fragmented burned scars in China.Here we developed an automated burned area mapping algorithm that was implemented using Sentinel-2 Multi Spectral Instrument(MSI)data and its effectiveness was tested taking Songnen Plain,Northeast China as a case using satellite image of 2020.We employed a logistic regression method for integrating multiple spectral data into a synthetic indicator,and compared the results with manually interpreted burned area reference maps and the Moderate-Resolution Imaging Spectroradiometer(MODIS)MCD64A1 burned area product.The overall accuracy of the single variable logistic regression was 77.38%to 86.90%and 73.47%to 97.14%for the 52TCQ and 51TYM cases,respectively.In comparison,the accuracy of the burned area map was improved to 87.14%and 98.33%for the 52TCQ and 51TYM cases,respectively by multiple variable logistic regression of Sentind-2 images.The balance of omission error and commission error was also improved.The integration of multiple spectral data combined with a logistic regression method proves to be effective for burned area detection,offering a highly automated process with an automatic threshold determination mechanism.This method exhibits excellent extensibility and flexibility taking the image tile as the operating unit.It is suitable for burned area detection at a regional scale and can also be implemented with other satellite data.
基金sponsored by the State Key Research and Development Program of China(2016YFC1402800)the Basic R&D Fund for Central Level Public Service Research Institute,China(DQJB17T01)the National Natural Foundation of China(U1434210,51421005)
文摘After the occurrence of an earthquake,strong motion observation networks can record ground motion at distributed observation stations. Based on the ground motion parameters from these records,the spatial distribution of seismic intensity can be quickly determined,and the degree of damage in different areas can be estimated. This information provides the technical basis for the emergency response,so as to ensure that rescue teams can reach extreme earthquake areas and carry out the search and rescue operation in an accurate and timely manner to reduce casualties and property loss. In this paper,we introduced 7 intensity algorithms and compared the results with the records of the Jiuzhaigou M_S7. 0 earthquake. We found that the differences between the instrumental intensities calculated by each method and the macro intensities were within a 1-degree range,which suggested good practicality of these different methods. The results calculated by the industrial standards-based calculation method and the integrated test showed good consistency.
