Aquarius/SAC-D Salinity Satellite Mission and the Ocean Observing System. NOAA/CPO Climate Observation Division 6th Annual System Review 3-5 September 2008 Silver Spring, MD. Gary Lagerloef Aquarius Principal Investigator. AQUARIUS/SAC-D Science Workshop Puerto Madryn, Argentina,
Aquarius/SAC-D Salinity Satellite Mission and the Ocean Observing System
NOAA/CPO Climate Observation Division 6th Annual System Review
3-5 September 2008
Silver Spring, MD
Aquarius Principal Investigator
AQUARIUS/SAC-D Observing SystemScience Workshop
Puerto Madryn, Argentina,
3-6 December 2008
Oceanography, Vol. 21, No. 1
Aquarius/SAC-D Observatory Observing System
International Partnership between United States – Argentina
3 beams Observing System390 km wide swath.
76 x 94 km
96 x 156 km
84 x 120 kmMission Design and Sampling Strategy
Sun-synchronous exact repeat orbit
6pm ascending node
Altitude 657 km
Beams point toward the night side to avoid sun glint
In Orbit Checkout
150km, Monthly, 0.2 (pss)
22 May 2010
30 day mean Input SSS field
30 day men Retrieved SSS field
30 day SSS retrieval bias
30 day SSS retrieval error standard deviation
Note degradation in high latitudes, especially southern ocean
Individual 5.6 second sample standard deviation error
While these simulator results look very promising, we a certain to have overlooked something…
Mean bias error
Zonal mean SST
Frank Wentz and Sab Kim, Remote Sensing Systems; Aquarius Algorithm Development Team
Constrain the complete surface atmosphere/ocean hydrologic [seasonal] cycle based on observations
Test and improve coupled climate models
Oceanography, Vol. 21, 2007
26 N ExperimentPotential Process Study in 2011
Air-Sea Freshwater Budget Study
Discussion group meeting at WHOI 9-10 July 2008: Ray Schmitt, Eric Lindstrom, Steve Riser, Arnold Gordon, Bill Large, Jim Carton, Fred Bingham, Gary Lagerloef, Lisan Yu, David Fratantoni
Convergence Zone and Weak Advection
Wind stress curl
Arnold. GordonNorth Atlantic Salinity Maximum
What processes maintain the salinity maximum?
Where does the excess salt go?
What processes give rise to temporal variability?
What is the larger impact on the shallow overturning circulation?
GOSUD ExperimentAquarius and Integrated In Situ Observations
Integrated Satellite + in situ Salinity Observing System
TAO Buoy 2S 165E Experiment
Delcroix & McPhaden, JGR 2002)TAO Array SSS
The RMS difference between satellite and in situ data comprises several terms:
εOis an error due to the spatial offset between the satellite and in situ samples (~0.2 psu; likely to be the largest term).
εPis thedifference error between a point salinity measurement and the area average over the instantaneous satellite footprint (log-normal distribution, median ~0.05 psu, extremes ~0.5).
εZis the difference error between the skin depth (~1-2 cm) salinity and in situ instrument measurement generally at 0.5 m to 5 m depth (can be >1 psu in rain).
εCis the in situ sensor calibration error, usually very small (<0.05 psu)
Provided by Gary Lagerloef and John Gunn
Purpose: To obtain “skin” salinity and upper 5m gradient statistics
9-month drifts <~0.06 Experiment
DecDrifters SSS: COSMOS 2005 Field Test, Bay of Biscay
Reverdin et al., JTech, 2007
Ready for more extensive SSS trials
Parallel effort at WHOI
50-100 SSS Drifters in the N. Atlantic Subtropical gyre by 2011.
~50 Enhanced STS Argo in high rainfall and high evaporation regimes.
~50 SSS Drifters in the Southern Ocean (large satellite error)