The performance of Harmony's two-dimensional sea-ice-drift observations

Poster (2019)

Authors

M. Kleinherenbrink Mathematical Geodesy and Positioning - CEG
Paco López-Dekker Mathematical Geodesy and Positioning - CEG
Julienne Stroeve University College London
Thomas Newman University College London
Pierre Rampal Nansen Environmental and Remote Sensing Center
Anton Korosov Nansen Environmental and Remote Sensing Center
Juliet Biggs University of Bristol
Andrew Hooper University of Leeds
Jeremie Mouginot University of California
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Research Group
Mathematical Geodesy and Positioning (CEG) (TU Delft)
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Published Date

2019

Language

English

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Faculty

Civil Engineering & Geosciences

Department

Geoscience and Remote Sensing

Research Group

Mathematical Geodesy and Positioning

Abstract

Sea-ice motion is driven by wind and ocean stress, and varies in space and time.
Small-scale drifts primarily affect the opening of leads, while large-scale drift primarily controls the loss of sea ice.
Both the opening of leads and the loss of sea ice play a major role in the energy balance of the Arctic and Antarctic regions.
Understanding sea-ice drift is therefore important for modelling and projecting regional and global climate change.
Accurately modelling sea ice and its dynamics requires high-resolution vectorized observations in the polar regions. Synthetic Aperture Radar (SAR) has proven to be a useful tool in the observations of sea-ice drift.
Most of the SAR-derived sea-ice-drift estimates make use of feature tracking, which depend on two SAR acquisitions.
This limits the temporal resolution and has the tendency to underestimate the sea-ice drift velocity by 10-20%.
Single-pass sea-ice-drift velocities can be inferred from SAR data using Doppler centroid anomaly estimation, but it is limited to the line-of-sight direction and has a resolution of several kilometers.
The only single-pass interferometric observations of sea ice were made using Tandem-X Along-Track Interferometry (ATI).
Its high sensitivity enables the determination of high-resolution sea-ice drift and also to estimate the rotations of individual floes.
However, as with the other two methods, Tandem-X is only sensitive to the line-of-sight. One of the main objectives of Earth Explorer 10 candidate Harmony is the observation of sea-ice drift.
We will present the first results of a performance analysis of Harmony's observations over sea ice.
The passive instruments onboard the Harmony satellites will use Sentinel-1 as an illuminator to provide multistatic observations of the sea-ice surface.
Harmony's reconfigurable constellation can either be optimized for a large line-of-sight difference (Stereo) or for range-direction sensitivy (ATI).
In the Stereo configuration, it will be possible, for the first time, to obtain instantaneous sea-ice drift vectors.
The ATI configuration enables Harmony to acquire high-resolution sea-ice-velocity estimates.
As Sentinel-1 is operating in the wide-swath mode over most of the sea ice covered areas, the polar region is sampled once every 1-4 days.