The twin optical Sentinel-2 A/B satellites, with their 5-day repeat observations, have proven to be capable of deriving high temporal resolution glacier velocity fields. This study proposes a data processing procedure for deriving quasi-monthly glacier flow velocity fields for the “Karakoram-Pamir anomaly” region. Each Sentinel-2 acquisition is performed offset-tracking (OT) to its next three almost cloud-free acquisitions to increase number of redundant observations. The detector mosaicking errors are eliminated for the two different Sentinel-2 satellites OT. A preliminary flow speed and direction referenced method is taken to remove the wrong matching of OT, and an iterative SVD (singular value decomposition) method solves the glacier velocity time series and removes the observation with large residual. Between Oct 2017 and Sep 2021, the derived results capture several surged glaciers initiating and/or ending their surging phases throughout the region. Additionally, two types of surging glaciers are identified solely on the basis of their high temporal resolution flow rates time series. The first type exhibits a short surging phase of just a few years and exhibited no seasonal variation in their flow rates, as exemplified by Rimo's southern tributary, which experienced a full surging phase lasting for approximately two years and reaching maximum speeds exceeding 10 m/day within the study period. The second type behaves similarly to normal glaciers, albeit with a glacier front that advances and exhibits much higher summer speeds (>3.5 m/day) than during stagnation, such as Gando at western Pamir. Normal glaciers exhibit annual speed-ups and slowdowns, with acceleration typically beginning in late April or early May and ending before September.

中文翻译：

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Sentinel-2 图像得出的西昆仑山、喀喇昆仑山、兴都库什和帕米尔的准月流速揭示了不同的冰川涌动模式


双光学 Sentinel-2 A/B 卫星经过 5 天的重复观测，已被证明能够获得高时间分辨率的冰川速度场。本研究提出了一种数据处理程序，用于推导“喀喇昆仑-帕米尔异常”地区的准月冰川流速场。每个 Sentinel-2 采集都会对其接下来的三个几乎无云的采集执行偏移跟踪 (OT)，以增加冗余观测的数量。两颗不同的 Sentinel-2 卫星 OT 的探测器镶嵌误差被消除。采用初步参考流速和方向的方法去除OT的错误匹配，并采用迭代SVD（奇异值分解）方法求解冰川速度时间序列并去除残差较大的观测值。 2017 年 10 月至 2021 年 9 月期间，得出的结果捕捉到了整个地区多个涌动冰川开始和/或结束的涌动阶段。此外，两种类型的汹涌冰川仅根据其高时间分辨率流速时间序列来识别。第一种类型表现出短短几年的短暂涌动阶段，流量没有季节性变化，例如里莫的南部支流，它经历了持续大约两年的完整涌动阶段，最高流速超过 10 m/天学习期限内。第二种类型的行为与正常冰川类似，尽管冰川前缘前进并表现出比停滞期间更高的夏季速度（> 3.5 m/天），例如帕米尔高原西部的甘多冰川。正常冰川每年都会加速和减速，加速通常在四月底或五月初开始，在九月之前结束。