首页|Monitoring firn and wet snow on mountain glaciers:polarization and orbit effects

Monitoring firn and wet snow on mountain glaciers:polarization and orbit effects

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Mountain glaciers are sensitive to climate variability and can be of great importance for downstream populations due to their hydrological significance.Synthetic Aperture Radar(SAR)images are often used to monitor the characteristics of glaciers based on the back-scattering coefficient.However,the influence of satellite orbit and polarization when collecting images for wide regions has not been well considered.This study focuses on the extraction of wet snow in summer and firn in winter in West Kunlun Shan and the Tibet Interior Mountains by using Sentinel-1 C-band SAR data.The investigated regions have different climate patterns.We compare backscatter coefficient distributions for wet snow and firn,derived from maximum likelihood classification under various polarizations,alongside their respective ratios and show that polarization has a minor impact on the identification and monitoring of both wet snow and firn.However,a comparison of the wet snow ratios at different satellite orbits reveals notable differences between ascending and descending orbits in summer.We furthermore show,by analyzing weather stations on glaciers,that such effect can be related to the different acquisition time and different temperatures in the morning and afternoon and therefore to the orbit.In contrast,firn ratios across different orbits show less variation in winter,and the monitoring results consistently align with the patterns of ablation and accumulation typical under both climatic influences.These findings demonstrate glaciers'sensitivity to temperature fluctuations and the radar wave's responsiveness to surface characteristics.Consequently,when employing SAR for glacier monitoring,it is crucial to consider the influence of orbit and polarization,in combination with temperature variations,and whether the season is winter or summer.

Continental glacierSynthetic Aperture Radar(SAR)wet snowfirnradar glacier zones

Ying Huang、Lei Huang、Tobias Bolch

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Institute of Geology,China Earthquake Administration,Beijing,China

International Research Center of Big Data for Sustainable Development Goals,Beijing,China

Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing,China

Institute of Geodesy,Graz University of Technology,Graz,Austria

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2024

地球空间信息科学学报(英文版)
武汉大学(原武汉测绘科技大学)

地球空间信息科学学报(英文版)

影响因子:0.207
ISSN:1009-5020
年,卷(期):2024.27(3)