Time series of transient snowline altitudes for High Mountain Asia, 1986–2021, derived from remote sensing data using Google Earth Engine

<em>Please note that this dataset represents a preliminary version for review and quality checking purposes.</em> <br> Here we present a dataset of Transient Snowline Altitude (TSLA) measurements for glaciers in High Mountain Asia (HMA) based on Landsat satellite imagery and digital elevation model data. The data were obtained using the MountAiN glacier Transient snowline Retrieval Algorithm (MANTRA), a Google Earth Engine tool to measure the average altitude of the snow-ice boundary. <br> Each MANTRA result consists of reference data (e.g. Landsat scene, date, glacier ID), relevant topographic metrics (glacier area, minimum and maximum elevation of the glacier), results of the surface material classification (areas covered by ice, snow, debris and clouds), summary statistics of the TSLA measurement, and quality metrics (cloud cover close to snow-ice boundary, class coverage). <br> For the dataset presented here, we applied MANTRA to all glaciers in HMA with an area larger than 0.5 km² (ca. 28,500 based on Randolph Glacier Inventory v6 glacier outlines). After filtering and postprocessing, the dataset comprises ca. 9.66 million TSLA measurements with an average of 341 ± 160 measurements per glacier, covering the time span 1986 to 2021. <br> Time series of Transient Snowline Altitude (TSLA) metrics for glaciers in High Mountain Asia, 1986 to 2021. The file is in NetCDF format, with the date of the Landsat measurement (LS_DATE) as index. Individual glacier are identified through Randolph Glacier Inventory v6 IDs (RGI_ID). The recommended metric to use for analyses is the median elevation of the detected TSLA range (TSLrange_median_masl).

请注意：本数据集为供审阅与质量核查使用的预发布版本。

本数据集呈现了基于Landsat卫星影像与数字高程模型（digital elevation model, DEM）数据获取的高亚洲（High Mountain Asia, HMA）冰川瞬时雪线高度（Transient Snowline Altitude, TSLA）测量数据集。数据通过MountAiN冰川瞬时雪线反演算法（MountAiN glacier Transient snowline Retrieval Algorithm, MANTRA）获取，该工具是一款用于测量雪冰边界平均海拔的谷歌地球引擎（Google Earth Engine）平台工具。

每条MANTRA结果包含参考数据（如Landsat影像场景、采集日期、冰川ID）、相关地形指标（冰川面积、冰川最低与最高海拔）、地表物质分类结果（冰、雪、碎屑与云覆盖区域）、TSLA测量的汇总统计量，以及质量指标（雪冰边界附近云量、类别覆盖占比）。

针对本次发布的数据集，我们对高亚洲范围内面积大于0.5 km²的所有冰川运行了MANTRA算法（基于伦道夫冰川目录v6（Randolph Glacier Inventory v6, RGI）的冰川轮廓，共计约28500条冰川）。经筛选与后处理后，本数据集包含约966万条TSLA测量值，单冰川平均测量次数为341±160次，时间跨度为1986年至2021年。

本数据集涵盖1986至2021年高亚洲冰川的TSLA指标时间序列，文件格式为NetCDF，以Landsat测量日期（LS_DATE）作为索引。单个冰川通过伦道夫冰川目录v6的ID（RGI_ID）进行标识。推荐用于分析的指标为检测到的TSLA范围的中位海拔（TSLrange_median_masl）。