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.
1. Landsat land satellite imagery data
From the website of the United States Geological Survey（ https://www.usgs.gov/ ）Geospatial Data Cloud（ http://www.gscloud.cn/ ）Download.
2. ASTER GDEM V3 data
The spatial resolution is 30 meters, download link https://lpdaac.usgs.gov/products/astgtmv003/ .
1. Remote sensing data preprocessing: Obtain glacier surface albedo through radiometric calibration, atmospheric correction, terrain correction, BRDF correction, and narrow wide band conversion.
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.
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.
| # | number | name | type |
| 1 | 2023NCDC008 | Compilation and Integration of the Tianshan Glaciers Data Resource System | NCDC Open Fund Project |
This work is licensed under
CC BY 4.0 (Creative Commons Attribution 4.0 International License).
CSTR:11738.11.NCDC.TIANSHAN.DB7116.2026
10.12072/ncdc.tianshan.db7116.2026
