{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,5]],"date-time":"2025-12-05T12:29:53Z","timestamp":1764937793550,"version":"build-2065373602"},"reference-count":51,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2024,9,9]],"date-time":"2024-09-09T00:00:00Z","timestamp":1725840000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["42130516","42171139"],"award-info":[{"award-number":["42130516","42171139"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The glacier surface is composed not only of ice or snow but also of a heterogeneous mixture of various materials. The presence of light-absorbing impurities darkens the glacier surface, reducing local reflectance and thereby accelerating the glacier melting process. However, our understanding of the spatial distribution of these impurities remains limited, and there is a lack of studies on quantifying the dirty degree of glacier surfaces. During the Sentinel satellite overpass on 21 August 2023, we used an ASD FieldSpec3 spectrometer to measure the reflectance spectra of glacier surfaces with varying degrees of dirtiness on the Qiyi glacier, Qinghai\u2013Tibet Plateau. Using Multiple Endmember Spectral Mixture Analysis (MESMA), the Sentinel imagery was decomposed to generate fraction images of five primary ice surface materials as follows: coarse-grained snow, slightly dirty ice, moderately dirty ice, extremely dirty ice, and debris. Using unmanned aerial vehicle (UAV) imagery with a 0.05 m resolution, the primary ice surface was delineated and utilized as reference data to validate the fraction images. The findings revealed a strong correlation between the fraction images and the reference data (R2 \u2265 0.66, RMSE \u2264 0.21). Based on pixel-based classification from the UAV imagery, approximately 80% of the glacier surface is covered by slightly dirty ice (19.2%), moderately dirty ice (33.3%), extremely dirty ice (26.3%), and debris (1.2%), which significantly contributes to its darkening. Our study demonstrates the effectiveness of using Sentinel imagery in conjunction with MESMA to map the degree of glacier surface dirtiness accurately.<\/jats:p>","DOI":"10.3390\/rs16173351","type":"journal-article","created":{"date-parts":[[2024,9,9]],"date-time":"2024-09-09T10:42:22Z","timestamp":1725878542000},"page":"3351","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Quantifying Qiyi Glacier Surface Dirtiness Using UAV and Sentinel-2 Imagery"],"prefix":"10.3390","volume":"16","author":[{"given":"Jiangtao","family":"Chen","sequence":"first","affiliation":[{"name":"Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi\u2019an 710127, China"},{"name":"Institute of Earth Surface System and Hazards, College of Urban and Environmental Sciences, Northwest University, Xi\u2019an 710127, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3612-1141","authenticated-orcid":false,"given":"Ninglian","family":"Wang","sequence":"additional","affiliation":[{"name":"Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi\u2019an 710127, China"},{"name":"Institute of Earth Surface System and Hazards, College of Urban and Environmental Sciences, Northwest University, Xi\u2019an 710127, China"},{"name":"State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China"}]},{"given":"Yuwei","family":"Wu","sequence":"additional","affiliation":[{"name":"Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi\u2019an 710127, China"},{"name":"Institute of Earth Surface System and Hazards, College of Urban and Environmental Sciences, Northwest University, Xi\u2019an 710127, China"}]},{"given":"Anan","family":"Chen","sequence":"additional","affiliation":[{"name":"Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi\u2019an 710127, China"},{"name":"Institute of Earth Surface System and Hazards, College of Urban and Environmental Sciences, Northwest University, Xi\u2019an 710127, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4735-2412","authenticated-orcid":false,"given":"Chenlie","family":"Shi","sequence":"additional","affiliation":[{"name":"Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi\u2019an 710127, China"},{"name":"Institute of Earth Surface System and Hazards, College of Urban and Environmental Sciences, Northwest University, Xi\u2019an 710127, China"}]},{"given":"Mingjie","family":"Zhao","sequence":"additional","affiliation":[{"name":"Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi\u2019an 710127, China"},{"name":"Institute of Earth Surface System and Hazards, College of Urban and Environmental Sciences, Northwest University, Xi\u2019an 710127, China"}]},{"given":"Longjiang","family":"Xie","sequence":"additional","affiliation":[{"name":"Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi\u2019an 710127, China"},{"name":"Institute of Earth Surface System and Hazards, College of Urban and Environmental Sciences, Northwest University, Xi\u2019an 710127, China"}]}],"member":"1968","published-online":{"date-parts":[[2024,9,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"364","DOI":"10.1038\/s41586-019-1822-y","article-title":"Importance and vulnerability of the world\u2019s water towers","volume":"577","author":"Immerzeel","year":"2020","journal-title":"Nature"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"759","DOI":"10.1016\/j.jenvman.2018.11.100","article-title":"Multi-risk assessment in mountain regions: A review of modelling approaches for climate change adaptation","volume":"232","author":"Terzi","year":"2019","journal-title":"J. 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