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Argo Update

Ming Ji, Ming Ji, NOAA/NCEP/OPC

Steve Piotrowicz, Ocean.US

David BehringerNOAA/NCEP/EMC

IGST, St John’s, NL CanadaAugust 7, 2007

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Active Argo Floats as of 30 June 2007

Countries: 44

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Network Growth

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Parking and Profiling Depths

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Float Survival Rate (all models)

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Argo Density – 27 July 2007

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Mean Age of the Argo Array - 26 July 2007

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The U.S. Argo Program

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(As of 07/07: Total = 2383 Deployed; 1606 Active, U.S. Argo Program = 2101 Deployed; 1517 Active)

United States Yearly Deployments

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Age Distribution of U.S. Floats

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Distribution of U.S. Argo Data to the GTS

Delays were due to Visual QC

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Argo Assimilation at NCEP

1. GODAS – Climate2. HYCOM – Ocean Weather

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The Argo array is providing deep temperature profiles for ocean analysis in numbers and coverage previously unavailable. Argo is also providing salinity profiles in numbers that are now practical for use in global analysis.

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Current operational GODAS

• Temperature profiles from Argo, XBTs, TAO moorings• The depth of the assimilation is 750 meters.

• Temperature profiles from Argo, XBTs, TAO moorings• The depth of the assimilation is 2200 meters.

Deep assimilation in GODAS-X

Assimilating deep Argo temperature profiles has improved the accuracy of the GODAS at mid-depths.

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Independent WOCE CTD section completed in 1988 & 1989 …

…and repeated in 2003 & 2005 by PMEL.

Standard

Deep

Standard vs. Deep assimilation

Shallow assimilation has a strong cold bias of1-3oC below 750 m.

Deep assimilation eliminates the cold bias.

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Current operational GODAS

• Temperature profiles from Argo, XBTs, TAO moorings• Salinity profiles are 100% synthetic (via TS-relationship)

• Temperature profiles from Argo and XBTs only• Salinity profiles are 75% observed (Argo) and

25% synthetic (XBTs)

Argo salinity in GODAS-A/S

Assimilating Argo salinity profiles has had an unexpected impact on tropical Pacific currents.

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AssimilatingArgo Salinity

Oper GODAS

GODAS-A/S

Salinity variability due to correlation with temperature.

Salinity variability introduced by observations.

Equatorial salinity section in the Pacific (vertical bars show positions of time-series below).

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Assimilating Argo Salinity

ADCP GODAS GODAS-A/S

In the east, assimilating Argo salinity reduces the bias at the surface and sharpens the profile below the thermocline at 110oW.

In the west, assimilating Argo salinity corrects the bias at the surface and the depth of the undercurrent core and captures the complex structure at 165oE.

Comparison with independent ADCP currents.

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R/V Kaharoa, operated by NIWA/New Zealand28 meters LOA, 300 tons.