CryoSat: showing the way to a future of improved ocean mapping

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CryoSatshowing the way to a futureof improved
ocean mapping

• Walter H. F. Smith
• NOAA Lab for Satellite Altimetry
• Silver Spring, Maryland

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Ocean altimetry of VD, G, and B
Sea surface slope reveals Vertical Deflection of
Gravity, and may be correlated with
Bathymetry. CryoSat offers first space-test of
improved resolution of VD, G B, with many
applications.
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Resolve Control on Ocean Mixing Rate
Slower Mixing
Faster Mixing
Smoother bottom
Rougher bottom
Spatial variations in bottom roughness change
mixing rates by order of magnitude (vertical
diffusivity lt 10?5at left and gt 10?4 at right
actual in situ data shown). 1030 km l
bathymetry controls mixing Higher-resolution
altimetry can map the controlling scales.
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Increase seamount detection 17x
Probably 50,000 seamounts 1 km tall remain
undetected. 2x better seamount resolution will
find 17x more seamounts.
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CryoSat showing the way ahead

• CryoSat is the first non-repeat-track (geodetic
  orbit) altimeter since ERS-1 (1994) and Geosat
  (1985).
• Sandwell et al. will use CryoSat conventional
  altimeter mode data over global ocean to improve
  marine gravity field.
• CryoSat SAR mode offers first space demonstration
  of delay-Doppler altimetry.
• Raney et al. will demonstrate improved ?H and
  reduced sensitivity to SWH over ocean surface.
• Smith et al. will demonstrate improved resolution
  of VD, G B over oceans.

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Ocean mapping beyond CryoSat

• An ocean mapping mission needs
• Geodetic (non-repeat) orbit
• SAR-mode over all ocean
• Moderate inclination

CryoSats polar orbit resolves only N-S component
of VD.
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Envisat measured the Indian Ocean tsunami
ESAs Envisat altimeter measured a sea level
anomaly on 26 Dec 2004 associated with the
tsunami. These data are being used at NOAA to
improve a model for the tsunami source mechanism
and wave field. Altimeters are the only source of
deep-water data on this tsunami. A NOAA press
release credits ESA for this valuable asset and
contribution.
See http//www.noaanews.noaa.gov/stories2005/s2365
.htm