Presentation on theme: "ECCO-2 and NASA Satellite Missions Lee-Lueng Fu Jet Propulsion Laboratory January 22-23, ECCO-2 Meeting."— Presentation transcript:
ECCO-2 and NASA Satellite Missions Lee-Lueng Fu Jet Propulsion Laboratory January 22-23, ECCO-2 Meeting
A snapshot of sea surface height anomalies from T/P and ERS altimeters
SSH wavenumber spectra (Ducet et al. 2000) T/P along- track T/P-ERS mapped T/P mapped Overlapping at 150 km Spatial scales of the AVISO T/P-ERS merged data
Small-scale Variability of the Ocean Unresolved by Nadir-looking Altimeter 100 km ground tracks of Jason (thick) and T/P (thin) Tandem Mission 100 km scale eddies resolvable by WSOA 10 km scale eddies Resolvable by HM
41.9º N 42.5º N < 10 km Coastal currents have scales less than 10 km < 10 km Observations made by ADCP offshore from the US West Coast T. Strub h ~ 5 cm v ~ 50 cm/sec
McWilliams (2006) Sub-mesoscale variability Sub-mesoscale processes are poorly observed but important to the understanding of the dissipation mechanism of ocean circulation. Radius of deformation
Altimetry SSH wavenumber spectrum Wavenumber (cycles/km) Power density (cm 2 /cycles/km) Noise level of HM for 2 cm measurement noise at 2 km resolution Jason pass 132 (147 cycle average) Stammer (1997) T/P ? ? Much reduced noise floor will enable the study of the spectrum at sub-mesoscales which have not been well resolved from existing data.
= 1cm/km (or 0.4 cm/7km) = 2cm/2km (or 1 cm/7km) = 2cm/7km For the three cases, velocity error is reduced from 7.8 to 3.6, 1.3 cm/sec at 25 km resolution; or 27, 15, 5 cm/sec at 10 km resolution Wavenumber (cyc/km) Velocity error (cm/s )2/ cyc/km Geostrophic velocity error spectrum 100 50 25 km k -2 spectrum
A Global Hydrosphere Mapper A SAR interferometry radar altimeter Near-global coverage with 16-day repeat orbit Same technique as WSOA – radar interferometry Use of SAR to enhance the along-track resolution 2 cm measurement precision at 2 km resolution 1 micro-radian precision in mean sea surface slope at 2 km resolution No data gap near the coast 8765432187654321 Number of Observation
Wide swath altimetry has been proposed as a surface water and ocean topography (SWOT) mission and favorably endorsed by the NRC Decadal Survey for a possible new mission in the time frame of 2013-2016.