CHAPTER 6
Wavelet Analysis of SAR Images in the Marginal Ice Zone
A. K. Lru AND C. Y. PENG
Contents
6.1 Introduction......................................................................................
111
6.2 Two-Dimensional Gaussian Wavelet......................................................
113
6.3 Wavelet Analysis for Ice Feature Tracking.............................................. 114
6.3.1 Chukchi Sea Marginal Ice Zone .......... .............................. ..................
115
6.3.2 Bering Sea Polynya...........................................................................
118
6.3.3 Tracking of Ice Floes......................................................................... 122
6.4 Discussion......................................................................................... 126
References............................................................................................... 127
6.1
Introduction
Ocean-ice interaction processes in the marginal ice zone (MIZ) by waves and mesoscale
features, such as upwelling and eddies, have been studied by using ERS-l SAR imagery
and wave-ice interaction models (Liu and Peng 1992, 1993a, 1994; Liu et al. 1993, 1997).
Satellite observations of mesoscale features and ice motion can playa crucial role in
ocean-ice interaction study. Ocean surface waves from the open sea may penetrate into
the MIZ and contribute to the breakup of floes and to other processes that modify the
ice cover. Using SAR imagery, the spatial variability of the wave and current field can
be estimated through spectral analysis and wave models. The wave-ice interaction
models take into account the physical characteristics of the ice cover and the wave parameters to predict wave dispersion, attenuation, refraction, and possibly ice thickness
(Liu et al. 1991, 1992; Liu 1995).
Mesoscale eddies are key features associated with the ice margin and are usually
attached to the ice edge. The models of surface effect associated with grease ice, wavecurrent interaction, and atmospheric instability due to upwelling have been used to
interpret the mesoscale features of eddies and fronts from ERS-l SAR images (Liu and
Peng 1993a; Liu et al. 1994a). Typical scales of these eddies are 20-40 km. Rotation was
mainly cyclonic with a maximum speed of up to 40 cm/s. Eddies play important roles
in the distribution of heat, mass, and momentum fluxes in polar regions and in the control of the ice edge and its locations. They may directly affect the loss of ice by moving
ice into warmer water which enhances ice melt and thereby the lateral mixing of heat.
The ice edge has been found to be highly productive for spring bloom and fishery feedAnalysis of SAR Data of the Polar Oceans
Edited by C. Tsatsoulis and R. Kwok
© Springer-Verlag Berlin Heidelberg 1998
Wavelet Analysis of SAR Images in the Marginal Ice Zone
A. K. Lru AND C. Y. PENG
Contents
6.1 Introduction......................................................................................
111
6.2 Two-Dimensional Gaussian Wavelet......................................................
113
6.3 Wavelet Analysis for Ice Feature Tracking.............................................. 114
6.3.1 Chukchi Sea Marginal Ice Zone .......... .............................. ..................
115
6.3.2 Bering Sea Polynya...........................................................................
118
6.3.3 Tracking of Ice Floes......................................................................... 122
6.4 Discussion......................................................................................... 126
References............................................................................................... 127
6.1
Introduction
Ocean-ice interaction processes in the marginal ice zone (MIZ) by waves and mesoscale
features, such as upwelling and eddies, have been studied by using ERS-l SAR imagery
and wave-ice interaction models (Liu and Peng 1992, 1993a, 1994; Liu et al. 1993, 1997).
Satellite observations of mesoscale features and ice motion can playa crucial role in
ocean-ice interaction study. Ocean surface waves from the open sea may penetrate into
the MIZ and contribute to the breakup of floes and to other processes that modify the
ice cover. Using SAR imagery, the spatial variability of the wave and current field can
be estimated through spectral analysis and wave models. The wave-ice interaction
models take into account the physical characteristics of the ice cover and the wave parameters to predict wave dispersion, attenuation, refraction, and possibly ice thickness
(Liu et al. 1991, 1992; Liu 1995).
Mesoscale eddies are key features associated with the ice margin and are usually
attached to the ice edge. The models of surface effect associated with grease ice, wavecurrent interaction, and atmospheric instability due to upwelling have been used to
interpret the mesoscale features of eddies and fronts from ERS-l SAR images (Liu and
Peng 1993a; Liu et al. 1994a). Typical scales of these eddies are 20-40 km. Rotation was
mainly cyclonic with a maximum speed of up to 40 cm/s. Eddies play important roles
in the distribution of heat, mass, and momentum fluxes in polar regions and in the control of the ice edge and its locations. They may directly affect the loss of ice by moving
ice into warmer water which enhances ice melt and thereby the lateral mixing of heat.
The ice edge has been found to be highly productive for spring bloom and fishery feedAnalysis of SAR Data of the Polar Oceans
Edited by C. Tsatsoulis and R. Kwok
© Springer-Verlag Berlin Heidelberg 1998