SAR-derived flow velocity and its link to glacier surface elevation change and mass balance Public Deposited

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  • Modern remote sensing techniques, such as Synthetic Aperture Radar (SAR), can measure the direction and
    intensity of glacier flow. Yet the question remains as to what these measurements reveal about glaciers’
    adjustment to the warming climate. Here, we present a technique that addresses this question by linking the SARderived
    velocity measurements with the glacier elevation change and the specific mass balance (i.e. mass balance
    per unit area). The technique computes the speckle offset tracking results from the north, east and vertical flow
    displacement time series, with the vertical component further split into a Surface Parallel Flow (SPF) advection
    component due to the motion along a glacier surface slope and a non-Surface Parallel Flow (nSPF). The latter
    links the glacier surface elevation change with the specific mass balance and strain rates. We apply this technique
    to ascending and descending Sentinel-1 data to derive the four-dimensional flow displacement time series for
    glaciers in southeast Alaska during 2016–2019. Time series extracted for a few characteristic regions demonstrate
    remarkable temporal variability in flow velocities. The seasonal signal observed in the nSPF component is
    modeled using the Positive Degree Day model. This method can be used for computing either mass balance or
    glacier surface elevation change if one of these two parameters is known from external observations.

Date Issued
  • 2021
Academic Affiliation
Journal Title
Journal Volume
  • 258
Last Modified
  • 2023-01-10
Resource Type
Rights Statement
  • 0034-4257