Aquarius Sea Surface Salinity satellite mission validation using near real-time, in-situ oceanographic data

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Aquarius Sea Surface Salinity satellite
mission validation using near real-time, in-situ
oceanographic data
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International Partnership Mission

• Service Platform and SAC-D Science Instruments
• Mission Operations Ground System

• Aquarius Salinity Microwave Instrument
• Launch Vehicle

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Single Day Orbit Swath Pattern
The orbit precesses to yield complete coverage in
7 days
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Mission 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 Check out
Surface Validation
Aquarius Ground System
Launch March 2009
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The Aquarius Validation Data Segment (AVDS) will
collect and process surface measurements for the
Aquarius data processing
AVDS

• Liaison with observers
• Daily data acquisition
• Quality control/editing
• Uniform data format

Deliver surface calibration data to Aquarius and
SMOS Data Processing Centers
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AVDS In-situ Data Sources
Validation Data Sampling Parameters
Platform Quantity Type Distribution Min Depth Latency
Argo Buoys 300/day Profile float Ocean-wide 5m 1 day
TAO/Triton1 36 of 68 With salinity Mooring Tropical Pac 1m 1 day
PIRATA 15 Mooring Tropical Atl 1m 1 day
GDP buoys2 Sfc Salinity 50 to 300 Surface drifter Ocean-wide 0.5 m 2 mos
Shipboard Thermo- salinograph varies Hull-mounted Ocean-wide 5m 2 days
GTSPP varies CTD profile Ocean-wide 1m TBD
1Funding for additional sensors and 50 additional
buoys planned for FY07 2Funding for 50 buoys with
near surface S sensors in FY07 ramping up to 300
in FY09
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In-situ data
Via ftp
daily
Validation data
USERS
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AVDS-ADPS Interaction

• AVDS provides
• Position (latitude, longitude)
• Time
• Acceptable deltas for position and time
• Format is ASCII
• Other identifying information (TBD)
• ADPS returns
• All Aquarius data collected within position and
  time windows
• Format is ASCII
• Include brightness Temp (TB), derived salinity,
  position, time
• of Level 2 data (along track)
• Other identifying information (TBD)

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User Community Products

• AVDS will provide the following to the surface
  salinity user community
• Tabular collection of in-situ and Aquarius SSS
  data for matched pairs
• Description of statistical selection process by
  in-situ data type
• Access to match-up criteria, in-situ data and
  edited, tabular coincident
• measurements via data servers, as shown below.

AVDS
In-situ data base
Edited, tabulated Coincident meas.
Position, time Window for matchup
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• Exchange formats between AVDS and ADPS will use
  an established system developed for the SeaWifs
  system
• The existing format structure will require only
  slight modifications to adapt to the Aquarius
  validation requirements

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Surface Current Data validation

• ESR Satellite derived surface currents with
  validation using GDP buoys

www.oscar.noaa.gov
www.esr.org
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Desired Validation Database Attributes

• Searchable in time and space
• Reasonable level of Quality Control
• Format with comfortable ease-of-use
• Source Traceability and documentation (metadata)
• Internet access to data in near real-time (lt 1
  week delay)
• Two examples follow GOSUD thermosalinograph
  underway data and ARGO profiling buoys data

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GOSUD Data Distribution 2006

• Data is stored by year and ship
• 2006 data as of end of April 2006
• Distribution somewhat constant in time (5-6K
  point per week)
• Some outliers in position
• Cruise tracks repeated (limited mid-Pacific
  coverage)

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ARGO Data Distribution

• Data is stored in daily files
• Two consecutive days in April
• Number of data points drops but distribution in
  time is similar
• Duplicate points exist for April 24th data (can
  affect statistics)

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Conclusions

• Access and ease of use for global data bases are
  significantly improved over the last few years
• Aquarius will require access to validation in
  near real-time mode. As such, initial QC is very
  important
• Idiosyncrasies of various validation data sets
  will require careful evaluation in their
  application to satellite fields
• Delayed mode data (high QC level) will be
  important for re-analysis efforts but are
  probably delayed too long for use in validating
  initial data distribution