本数据集利用消融期末（每年7月20日-9月20日）Landsat影像，结合ArcGIS、ENVI软件和Google Earth影像，基于积雪和裸冰反照率值差异显著的特性以及遥感反演的整条冰川范围的反照率果，提取了天山乌鲁木齐河源区7条冰川2002-2022年消融期末的雪线高度数据（单位：m）。", "ds_source": "
1. Landsat陆地卫星影像数据\n
从美国地质调查局网站(https://www.usgs.gov/)和地理空间数据云(http://www.gscloud.cn/)下载。\n
2. ASTER GDEM V3数据\n
空间分辨率为30米，下载地址 https://lpdaac.usgs.gov/products/astgtmv003/。", "ds_process_way": "
1. 遥感数据预处理：通过辐射定标，大气校正、地形校正、BRDF校正以及窄-宽波段转换的方法反演获得冰川表面反照率。\n
2. 雪线高度识别：利用冰川区DEM和遥感反演反照率结果，以50 m等高线间隔计算冰川中流线（中流线附近7个像元，约210 m范围）附近各海拔带的反照率值、标准差，得到中流线上反照率随海拔的变化曲线。曲线上标准差最大点表明该海拔带内冰面类型差异最大，为积雪区与裸冰区的过渡带，其反照率值记为α。随着海拔的升高，自该海拔带以上的区域为积雪区，以下为裸冰区。因此，将α作为雪线提取的阈值，将冰川表面划分为积雪区和裸冰区，积雪区下界即为雪线。但是，冰川雪线高度不一定沿等高线规则分布，很可能穿越几条等高线。在此，根据5 m间隔提取的等高线，取该线最邻近的等高线或者最邻近等高线的平均值作为最终雪线高度。", "ds_quality": "
数据精度：人工目视解译划定雪线高度与本研究提取的雪线高度差值在8-67米之间。", "ds_acq_start_time": "2002-07-01 00:00:00", "ds_acq_end_time": "2022-08-31 00:00:00", "ds_acq_place": "天山乌鲁木齐河源区", "ds_acq_lon_east": 86.81666666666666, "ds_acq_lat_south": 43.1, "ds_acq_lon_west": 86.75, "ds_acq_lat_north": 43.11666666666667, "ds_acq_alt_low": 3700.0, "ds_acq_alt_high": 4600.0, "ds_share_type": "apply-access", "ds_total_size": 9838, "ds_files_count": 2, "ds_format": "excel", "ds_space_res": "30", "ds_time_res": "年", "ds_coordinate": "WGS84", "ds_projection": "UTM", "ds_thumbnail": "23242418-9c07-4554-a064-73f9ab8eb9a8.png", "ds_thumb_from": 2, "ds_ref_way": "", "paper_ref_way": "", "ds_ref_instruction": "", "ds_from_station": null, "organization_id": "76330c66-832b-46b3-b501-f5f6edb08dc2", "ds_serv_man": "敏玉芳", "ds_serv_phone": "0931-4967596", "ds_serv_mail": "ncdc@lzb.ac.cn", "doi_value": "", "subject_codes": [ "170.99" ], "quality_level": 0, "publish_time": "2026-02-05 15:43:12", "last_updated": "2026-05-20 10:45:22", "protected": false, "protected_to": null, "lang": "zh", "cstr": "11738.11.NCDC.TIANSHAN.DB7116.2026", "i18n": { "en": { "title": "Final Snowline Height Data of Urumqi River Source Area Melting Period (2002-2022)", "ds_format": "excel", "ds_source": "
1. Landsat land satellite imagery data\r\n
From the website of the United States Geological Survey（ https://www.usgs.gov/ ）Geospatial Data Cloud（ http://www.gscloud.cn/ ）Download.\r\n
2. ASTER GDEM V3 data\r\n
The spatial resolution is 30 meters, download link https://lpdaac.usgs.gov/products/astgtmv003/ .", "ds_quality": "
Data accuracy: The difference between the manually interpreted snow line height and the snow line height extracted in this study is between 8-67 meters.", "ds_ref_way": "", "ds_abstract": "
This dataset utilizes Landsat images at the end of the melting period (July 20th to September 20th each year), combined with ArcGIS, ENVI software, and Google Earth images. Based on the significant difference in albedo values between snow cover and bare ice, as well as remote sensing inversion of albedo results for the entire glacier range, snow line height data (unit: m) of seven glaciers in the Ulumuqi River source area of Tianshan from 2002 to 2022 at the end of the melting period were extracted.", "ds_time_res": "", "ds_acq_place": "Tianshan Urumqi River Source Area", "ds_space_res": "", "ds_projection": "", "ds_process_way": "
1. Remote sensing data preprocessing: Obtain glacier surface albedo through radiometric calibration, atmospheric correction, terrain correction, BRDF correction, and narrow wide band conversion.\r\n
2. Snow line height recognition: Using DEM and remote sensing inversion of albedo results in glacier areas, calculate the albedo values and standard deviations of each altitude zone near the glacier centerline (7 pixels near the centerline, approximately 210 meters) at 50 meter contour intervals, and obtain the variation curve of albedo with altitude on the centerline. The point with the maximum standard deviation on the curve indicates that there is the greatest difference in ice surface types within this altitude zone, which is the transition zone between snow covered areas and bare ice areas. Its albedo value is denoted as α. As the altitude increases, the area above this altitude zone is the snow covered area, and the area below is the bare ice area. Therefore, using α as the threshold for snow line extraction, the glacier surface is divided into snow covered and bare ice areas, with the lower boundary of the snow covered area being the snow line. However, the height of glacier snow lines may not necessarily follow a regular distribution along contour lines and may cross several contour lines. Here, based on the contour lines extracted at 5-meter intervals, the nearest contour line or the average of the nearest contour lines is taken as the final snow line height.", "ds_ref_instruction": "" } }, "submit_center_id": "ncdc", "data_level": 0, "recommendation_value": 0, "license_type": "https://creativecommons.org/licenses/by/4.0/", "doi_reg_from": "reg_local", "cstr_reg_from": "reg_local", "doi_not_reg_reason": null, "cstr_not_reg_reason": null, "is_paper_in_submitting": false, "belong_to_nieer": false, "ds_topic_tags": [ "冰川", "消融期", "雪线高度" ], "ds_subject_tags": [ "地球科学其他学科" ], "ds_class_tags": [], "ds_locus_tags": [ "天山乌鲁木齐河源区" ], "ds_time_tags": [ 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022 ], "ds_contributors": [ { "true_name": "岳晓英", "email": "yuexiaoying@lzb.ac.cn", "work_for": "中国科学院西北生态环境资源研究院", "country": "中国" } ], "ds_meta_authors": [ { "true_name": "岳晓英", "email": "yuexiaoying@lzb.ac.cn", "work_for": "中国科学院西北生态环境资源研究院", "country": "中国" } ], "ds_managers": [ { "true_name": "岳晓英", "email": "yuexiaoying@lzb.ac.cn", "work_for": "中国科学院西北生态环境资源研究院", "country": "中国" } ], "category": "积雪" }