3 Role of SAR in Surface Energy Flux Measurements Over Sea Ice
are (1) to improve upon existing forward scattering models, (2) to develop the mathematical framework required for the development of inverse scattering models, and (3)
to explore the mathematical nature of transfer functions required to exploit the linkages amongst various electromagnetic frequency interactions within the marine cryosphere. Development of the forward scattering models (1) is being done at visible, thermal infrared and microwavelengths (over typical space-borne active and passive frequencies). These models are being used to improve our understanding of the primary
scattering mechanisms at these frequencies and thereby the linkages which exist
between the geophysics, dielectrics and electromagnetic interactions. The inverse scattering model development (2) is premised on the notion that, if we can precisely measure the scattered field, then the potential exists to invert through a physical model to
solve for a single geophysical variable which gives rise to the scattering. This work holds
promise as a means of geophysical inversion for variables such as ice thickness, snow
thickness, snow grain size, brine volume, etc. The exploration of the nature of transfer
functions (3) is, in effect, an extension of what has been presented in this chapter. The
objective here is to create a model which would have as an input the scattered electromagnetic field at frequency A" from which would be predicted the interactions at a different frequency A2 for a constant suite of geophysical and electrical characteristics of
the snow-covered sea ice. An example of the application of one such model would be
to observe the scattered field at 5.3 GHz (A-,) and predict the interactions at climatological short wavelengths (A2).
These developments, included with the diversity of approaches represented in the
other chapters in this volume, illustrate a broad, international effort to maximize the
use of synthetic aperture radar remote sensing for studies of high-latitude processes.
Collectively these research advances have resulted in a strong theoretical base upon
which we are now developing specific-use image products, process model inputs and
transfer functions amongst various frequencies of the electromagnetic spectrum.
These incremental developments are in turn being used by Earth system scientists in
development of a better understanding how the marine cryosphere interacts within an
Earth system, which we now know is susceptible to anthropogenic effects.
Acknowledgments. This work was supported by an NSERC grant, an Office of Naval
Research Grant, and a NASA grant for ASF data, each to D. Barber. Additional support
was provided by the Polar Continental Shelf Project, Canadian Ice Services, and the
Canada Centre for Remote Sensing. Numerous participants of the SIMMS field programs contributed their expertise: Ellsworth LeDrew, Roger De Abreu, Kevin Misurak,
and Chris Derksen. Thanks also to the staff at the Alaska SAR Facility for help with
acquisition and processing of ERS-1 data.
References
Agnew TA, Silis A (1994) Spring season climate variability at resolute bay, NWT, Canadian climate centre, Rep No 94-1,Atmospheric Environment Service, Downsview, Ontario
Barber DG, LeDrew EF (1994) On the links between microwave and solar wavelength
interactions within a seasonally dynamic snow covered sea ice volume. Arctic
47(3):298-309
are (1) to improve upon existing forward scattering models, (2) to develop the mathematical framework required for the development of inverse scattering models, and (3)
to explore the mathematical nature of transfer functions required to exploit the linkages amongst various electromagnetic frequency interactions within the marine cryosphere. Development of the forward scattering models (1) is being done at visible, thermal infrared and microwavelengths (over typical space-borne active and passive frequencies). These models are being used to improve our understanding of the primary
scattering mechanisms at these frequencies and thereby the linkages which exist
between the geophysics, dielectrics and electromagnetic interactions. The inverse scattering model development (2) is premised on the notion that, if we can precisely measure the scattered field, then the potential exists to invert through a physical model to
solve for a single geophysical variable which gives rise to the scattering. This work holds
promise as a means of geophysical inversion for variables such as ice thickness, snow
thickness, snow grain size, brine volume, etc. The exploration of the nature of transfer
functions (3) is, in effect, an extension of what has been presented in this chapter. The
objective here is to create a model which would have as an input the scattered electromagnetic field at frequency A" from which would be predicted the interactions at a different frequency A2 for a constant suite of geophysical and electrical characteristics of
the snow-covered sea ice. An example of the application of one such model would be
to observe the scattered field at 5.3 GHz (A-,) and predict the interactions at climatological short wavelengths (A2).
These developments, included with the diversity of approaches represented in the
other chapters in this volume, illustrate a broad, international effort to maximize the
use of synthetic aperture radar remote sensing for studies of high-latitude processes.
Collectively these research advances have resulted in a strong theoretical base upon
which we are now developing specific-use image products, process model inputs and
transfer functions amongst various frequencies of the electromagnetic spectrum.
These incremental developments are in turn being used by Earth system scientists in
development of a better understanding how the marine cryosphere interacts within an
Earth system, which we now know is susceptible to anthropogenic effects.
Acknowledgments. This work was supported by an NSERC grant, an Office of Naval
Research Grant, and a NASA grant for ASF data, each to D. Barber. Additional support
was provided by the Polar Continental Shelf Project, Canadian Ice Services, and the
Canada Centre for Remote Sensing. Numerous participants of the SIMMS field programs contributed their expertise: Ellsworth LeDrew, Roger De Abreu, Kevin Misurak,
and Chris Derksen. Thanks also to the staff at the Alaska SAR Facility for help with
acquisition and processing of ERS-1 data.
References
Agnew TA, Silis A (1994) Spring season climate variability at resolute bay, NWT, Canadian climate centre, Rep No 94-1,Atmospheric Environment Service, Downsview, Ontario
Barber DG, LeDrew EF (1994) On the links between microwave and solar wavelength
interactions within a seasonally dynamic snow covered sea ice volume. Arctic
47(3):298-309