john t. gunn, avds manager earth & space research 1910 fairview ave. e., suite 210 seattle, wa...

John T. Gunn, AVDS ManagerEarth & Space Research

1910 Fairview Ave. E., Suite 210Seattle, WA 98102

Ph: 206-726-0501; Email: [email protected]

1st Joint GOSUD/SAMOS WorkshopBoulder, Colorado

2-4 May, 2006

Aquarius Sea Surface Salinity satellite mission validation

using near real-time, in-situ oceanographic data

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Salinity Satellite Mission

GOSUD/SAMOS:John Gunn

• Aquarius Salinity Microwave Instrument

• Launch Vehicle

• Service Platform and SAC-D Science Instruments

• Mission Operations & Ground System

International Partnership Mission

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Single Day Orbit Swath Pattern

The orbit precesses to yield complete coverage in 7 days

The orbit precesses to yield complete coverage in 7 days

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390 km wide swath.

76 x 94 km 96 x 156 km

84 x 120 km

3 beams

Salinity Data

Surface Validation

Mission Design and Sampling Strategy

Beams point toward the night side to avoid sun glint

Beams point toward the night side to avoid sun glint

Launch March 2009

Launch March 2009

In Orbit

Check out

AquariusGround System

AquariusGround System

• Global Coverage in 7 Days• 4 Repeat Cycles per Month

• Global Coverage in 7 Days• 4 Repeat Cycles per Month

Sun-synchronous exact repeat orbit6pm ascending nodeAltitude 657 km

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Deliver surface calibration data to Aquarius and SMOS Data Processing Centers

Deliver surface calibration data to Aquarius and SMOS Data Processing Centers

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

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

The Aquarius Validation Data Segment (AVDS) will collect and process surface measurements for

the Aquarius data processing

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AVDS In-situ Data Sources

Platform Quantity Type Distribution Min Depth Latency

Argo Buoys ~300/day Profile float Ocean-wide 5m 1 day

TAO/Triton136 of 68

With salinityMooring 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

Validation Data Sampling Parameters

1Funding for additional sensors and 50 additional buoys planned for FY072Funding for 50 buoys with near surface S sensors in FY07 ramping up to 300 in FY09

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In-situ data

AVDSESR

AVDSESR

ADPSGSFC

ADPSGSFC

USERS

GTSPP

Validation data

Via ftpdaily

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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)

AVDS-ADPS Interaction

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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.

AVDSAVDS

In-situdata base

In-situdata base

Edited, tabulatedCoincident

meas.

Edited, tabulatedCoincident

meas.

Position, timeWindow for

matchup

Position, timeWindow 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 (< 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

john t. gunn, avds manager earth & space research 1910 fairview ave. e., suite 210 seattle, wa...

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