CHAPTER 3
Role of SAR in Surface Energy Flux Measurements Over Sea Ice
D.G. BARBER, A. THOMAS, AND T.N. PAPAKYRIAKOU
Contents
3·1 Introduction.......................................................................................
35
3.2 The Marine Cryosphere.......................................................................
36
3.2.1 Physical and Electrical Properties of Sea Ice ...................................•....
37
3.2.2 Energy Balance................................................................................
40
3.2.3 Microwave Scattering........................................................................
42
3.3 Building Statistical Relationships..........................................................
45
3.3.1 Univariate Analysis... ....... ........... ...... ... .... ........... ....... ............. .... ......
45
3.3.2 Multivariate Analysis ........................................................................
49
3.4 Generating Image Products..................................................................
50
3.4.1 Detecting Melt Onset with SAR.... ............. .... ... .... ....... .... ......... ...........
51
3.4.2 Scene Segmentation and Classification.... .... ....... ......... ............... .........
51
3.4.2.1 Classification.................................................................................
51
3.4.2.2 Segmentation................................................................................
54
3.4.3 Predicting Daily Average Shortwave Albedo (a) from aO........................ 57
3·4·3·1 Methods................. .................... ....... .... ....... .... ........... ......... .........
58
3.4.3.2 Results... ....... ........... ....... .... ........... ........... ............. ....... ....... .........
61
3.5 Conclusions and Future Directions... ........... ......... .... .................. .... .......
64
References...............................................................................................
65
3.1
Introduction
The ocean-sea ice-atmosphere interface (hereafter referred to as the marine cryosphere) is a major component of the high-latitude Earth system. Its presence or absence
over the polar oceans is an important factor in the overall heat exchange at high latitudes (e.g. Maykut 1978) and is generally accepted as an important component in the
climate system because of its potential to amplify small changes through a variety of
feedback mechanisms. Energy flows through the marine cryosphere as a function of
thermodynamic and dynamic processes, both of which affect, and in turn are affected
by, the physical properties of the volume. This results in an integrated system whereby
hydrospheric and atmospheric forcings are linked with changes in the geophysical and
electrical characteristics of the snow-covered sea ice volume.
Analysis of SAR Data of the Polar Oceans
Edited by C. Tsatsoulis and R. Kwok
© Springer-Verlag Berlin Heidelberg 1998
Role of SAR in Surface Energy Flux Measurements Over Sea Ice
D.G. BARBER, A. THOMAS, AND T.N. PAPAKYRIAKOU
Contents
3·1 Introduction.......................................................................................
35
3.2 The Marine Cryosphere.......................................................................
36
3.2.1 Physical and Electrical Properties of Sea Ice ...................................•....
37
3.2.2 Energy Balance................................................................................
40
3.2.3 Microwave Scattering........................................................................
42
3.3 Building Statistical Relationships..........................................................
45
3.3.1 Univariate Analysis... ....... ........... ...... ... .... ........... ....... ............. .... ......
45
3.3.2 Multivariate Analysis ........................................................................
49
3.4 Generating Image Products..................................................................
50
3.4.1 Detecting Melt Onset with SAR.... ............. .... ... .... ....... .... ......... ...........
51
3.4.2 Scene Segmentation and Classification.... .... ....... ......... ............... .........
51
3.4.2.1 Classification.................................................................................
51
3.4.2.2 Segmentation................................................................................
54
3.4.3 Predicting Daily Average Shortwave Albedo (a) from aO........................ 57
3·4·3·1 Methods................. .................... ....... .... ....... .... ........... ......... .........
58
3.4.3.2 Results... ....... ........... ....... .... ........... ........... ............. ....... ....... .........
61
3.5 Conclusions and Future Directions... ........... ......... .... .................. .... .......
64
References...............................................................................................
65
3.1
Introduction
The ocean-sea ice-atmosphere interface (hereafter referred to as the marine cryosphere) is a major component of the high-latitude Earth system. Its presence or absence
over the polar oceans is an important factor in the overall heat exchange at high latitudes (e.g. Maykut 1978) and is generally accepted as an important component in the
climate system because of its potential to amplify small changes through a variety of
feedback mechanisms. Energy flows through the marine cryosphere as a function of
thermodynamic and dynamic processes, both of which affect, and in turn are affected
by, the physical properties of the volume. This results in an integrated system whereby
hydrospheric and atmospheric forcings are linked with changes in the geophysical and
electrical characteristics of the snow-covered sea ice volume.
Analysis of SAR Data of the Polar Oceans
Edited by C. Tsatsoulis and R. Kwok
© Springer-Verlag Berlin Heidelberg 1998