ALPES_wFLAG_wKT_ANNUALv2016-2021.nc

This file includes 13 layers: • v2015-2016: Annually aggregated glacier surface flow velocity for the hydrological year 2015-2016 (the hydrological year starts the 1st of October and finishes the 30 of September of the following year). • v2016-2017: Same as before but for the hydrological year 2016-2017. • v2017-2018: Same as before but for the hydrological year 2017-2018. • v2018-2019: Same as before but for the hydrological year 2018-2019. • v2019-2020: Same as before but for the hydrological year 2019-2020. • v2020-2021: Same as before but for the hydrological year 2020-2021. • dir: Flow direction (= angle between the flow vector and x-axis, in radians). • cnt: Number of image pairs used to generate the displacement maps that have been aggregated to obtain the glacier surface flow velocity products (data per pixel). • stdev: Standard deviation on the velocity for each pixel. • stdeva: Standard deviation on the direction of the glacier surface flow. • flag: Error flag mask on pixels considered as unreliable. Such pixels have been flagged according to the following criteria: (i) coefficient of variation of the glacier surface flow velocity higher than 75% in order to mask areas with unreliable variability (e.g., glacier edges); (ii) standard deviation of the glacier flow direction higher than 2.5° in order to mask areas with unreliable flow direction changes. • trend_2015-2021: trend on surface flow velocity other the study period (2015-2021). • trend_mask: mask on pixels considered with a non-significant trend. Pixels showing time series with non-significant trend (Kendall rank of correlation test with a p-value > 0.05) are masked. Masked pixels: 0 Non-masked pixel. All maps are georeferenced under the UTM Z32N projection.

本数据集包含13个数据层：• v2015-2016：2015-2016水文年度（水文年度始于10月1日，止于次年9月30日）的年聚合冰川表面流速数据。• v2016-2017：同上，对应2016-2017水文年度。• v2017-2018：同上，对应2017-2018水文年度。• v2018-2019：同上，对应2018-2019水文年度。• v2019-2020：同上，对应2019-2020水文年度。• v2020-2021：同上，对应2020-2021水文年度。• dir：流向（即流速矢量与x轴的夹角，单位为弧度）。• cnt：用于生成位移图的图像对数量，该位移图经聚合后得到冰川表面流速产品（按像素统计的数值）。• stdev：各像素的流速标准差。• stdeva：冰川表面流向的标准差。• flag：不可靠像素的错误标记掩码。根据以下标准对不可靠像素进行标记：(i) 冰川表面流速的变异系数高于75%，以屏蔽变异性不可靠的区域（如冰川边缘）；(ii) 冰川流向的标准差高于2.5°，以屏蔽流向变化不可靠的区域。• trend_2015-2021：研究时段（2015-2021）内的表面流速变化趋势。• trend_mask：趋势不显著的像素掩码。当像素对应的时间序列趋势不显著（肯德尔秩相关检验的p值>0.05）时，将其标记为掩码像素。掩码像素值为0，非掩码像素保留原值。所有地图均采用UTM Z32N投影进行地理配准。