The Research On Surface Morphological Extraction Of Lake Ice Using Remote Sensing And The Impact Factors

Lake ice is one of the essential climate variables in the cryosphere,which can indicate long-term and short-term climate change.The change of lake ice is closely related to the winter climate and has received widespread public and academic attention.With the rapid development of the cold area economy,the safety of human activities on ice has been paid more and more attention.The surface morphology of lake ice is influenced by both thermal and dynamic processes,which is the energy transmission channel of the frozen lakes and the most hazardous area of the ice surface.Therefore,using multi-source remote sensing data to monitor the surface features of lake ice on a large scale and high frequency can provide a scientific basis and decision support for the management of the lakes environment and the safety protection of ice activities.In this paper,Chagan Lake in Jilin province is selected as the research area.And a framework of automatic extraction method based on spatial filtering,threshold segmentation,and fractal theory is proposed.The precision of the automatic extraction algorithm is verified by the results of visual interpretation from Landsat images,in which R~2 is more significant than 0.95 and MAE is less than 5%,indicating that the automatic extraction method is accurate and reliable.Aiming at the characteristics of rapid change and short duration of the freezing process and melting process,the fusion data of Landsat and GOCI were generated based on the ESTARFM data fusion model,the spatial resolution is 30 m,and the temporal resolution is one hour.The determination coefficient between the fused image and the actual image reaches 0.94,which shows that the error between the combined image and the actual image is small.The ESTARFM model can approximate the true reflectivity of the ground surface.Based on the MODIS LWST time series,the time window of ice surface morphology monitoring in the winter of 2018-2019 was determined.Based on high space-time remote sensing images,the ice surface features of Chagan Lake in the winter of 2018-2019 were acquired by the automatic extraction method,which was verified as ice ridge by field survey.The Ice Ridge experienced three growth stages,the mean length was 21141.57±68.36 m,and the mean azimuth angle was 335.48±0.23°.The azimuth angle is 86.22°,which is close to the vertical,indicating that the wind plays an essential role in the formation of the lake ice surface.