(HAPTER4
Extraction of Intermediate Scale Sea Ice Deformation
Parameters from SAR Ice Motion Products
S. LI, Z. CHENG, AND W.E WEEKS
Contents
4.1 Introduction
4.2 Background ............................................
71
4.2.1 Ice Motion Products .....................................
72
4.2.2 Derivation of Ice Deformation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
73
4.3 Algorithm Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
74
4.3.1 The Tie Point Locator ....................................
75
4.3.2 The Edge Point Trimmer ..................................
76
4.3.3 The Gap Filler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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4.3.4 The Deformation Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
78
4.3.5 The Extension Tracer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
78
4.4 Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
79
4.5 Accuracy in Estimation of Deformation Parameters ................
80
4.6 Examples and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
82
4.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
88
References
4.1
Introduction
In sea ice studies, there appear to be natural scale divisions (Overland et al.1995), and
the regional scale (10-50 km) is crucial because the processes on this scale interact with
both the climate scale (100-300 km) sea ice processes and floe scale (1 km) processes.
Understanding the intermediate regional scale sea ice deformation can help bridge the
gap between the sea ice behavior on the floe scale, which is in situ measurable, and the
one on the climate scale, which is used as a direct input to climate models. At the intermediate scale, the sea ice deformation behavior is observable from remote sensing data.
In fact, the current generation of Earth-viewing radar satellites provides regular observations of the behavior of large areas of the Arctic pack ice. Only the extremely large
image data stream poses difficulties for the rapid and efficient extraction of useful geophysical information, and thus requires the development of a variety of automated procedures. This is why the present chapter concentrates on the quantitative characterization of intermediate scale sea ice deformation.
Analysis of SAR Data of the Polar Oceans
Edited by C. Tsatsoulis and R. Kwok
© Springer-Verlag Berlin Heidelberg 1998