Argo Errors and Estimating Heat Content and Argo Errors

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Argo Errors and Estimating Heat Content and Argo
Errors
Argo Errors and Estimating Heat Content and Argo
Errors

• Josh K. Willis
• joshua.k.willis_at_jpl.nasa.gov
• Jet Propulsion Laboratory

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Overview

• Ocean cooling a rude awakening to depth
  errors
• Argo and altimeter data as calibration tools
• Time evolution of recent XBT biases
• Remaining errors

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The Problem
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Upper-Ocean cooling
from Lyman et al. (GRL, 2006)
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My brush with Rush
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(No Transcript)
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To overturn the world economy based on the
musings of a few idiot leftist scientists is just
stupid, and thats what Global Warming is all
about. ? Rush
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WHOI float distribution
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WHOI float biases
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A correction to recent cooling
Ocean Heat Content from 2004 to 2006
Removing the bad float data reduces the cooling
but does not completely eliminate it.
From Willis et al., GRL, in prep.
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XBT data is biased warm
Shallow XBTs have a bigger bias
from Wijffels et al., accepted.
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A correction to recent cooling
Ocean Heat Content from 2004 to 2006
Another bias XBTs are biased warm, which also
causes spurious cooling.
From Willis et al., GRL, in prep.
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XBT bias fall-rate errors pair analysis
Comparison of Isotherm Displacements
XBT/Argo pairs 12,000
Argo/CTD pairs 2,000
From Willis et al., GRL, in prep.
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Climatologies with XBT data bias warm
Levitus, WOA05 climatology
Gouretski Koltermann, WGHC climatology
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A Technique
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The pseudo pair
Correlation oefficient, r between SSH anomaly
and T(400 m)

• Much of upper ocean T variaibility is contained
  in SSH anomaly
• Use AVISO SSH maps to make pseudo temperature
  anomalies
• Tpseudo a(z) SSHA

From Wijffels et al., manuscript in prep.
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Pseudo-pair comparison
Comparison of Sippican Deep Blue probes with
nearby Argo pairs (2004 2006), 12,000

• Pseudo-pairs give same bias, but have narrower
  distribution
• More comprehensive means of test XBT bias because
  of SSH data availability

From Wijffels et al., manuscript in prep.
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Pseudo-pair analysis of other data(a.k.a.
sanity check)
Argo profile data
CTD data

• CTD data show no significant bias during any time
  period
• Argo floats show little bias except for WHOI/FSI
  floats

From Wijffels et al., accepted
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Other consistency checks
Pseudo profiles minus real float profiles for
3000 floats
Detecting corrections
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Corrections
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In the 1990s altimeter allows correction by
probe type
Time dependence of bias in Sippican Deep Blue XBT
probes

• Bias increases over time
• Hi bias in later years may reflect double
  application of Hanawa et al. (1995) correction

From Wijffels et al., manuscript in prep.
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Stretching factor by probe type
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Revised ocean heat content estimate
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Remaining problems
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Remaining Errors

• Skewness significant difference between mean and
  median
• Wire stretch or QC issue?

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Remaining Errors
Gaussian
Tail for positive depth error is much bigger
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Other stuff
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What causes globally-averagedsea level rise?
Total sea level rise


(roughly)
Argo
Jason
GRACE
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The recent sea level budget
Global Mean Sea Level
Global MSL, no seasonal
Total (Jason)
Total (Jason)
Steric (Argo)
Steric (Argo)
Mass (GRACE)
Mass (GRACE)
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Argo profiles, displacements and altimetry
2004 2006 mean SSH
Absolute geostrophic velocity from 0 to 2000 db
at 37N

• Altimeter is used to reduce eddy variability in
  both types of Argo data
• Integrating from 0 to 1000 m and from east to
  west may provide estimate of AMOC transport

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The recent sea level budget
Northward transport in upper 1000 m v. latitude
Transport at 45N by temperature classes

• Assume mass is closed below 2000 db.
• Time averaged meridional heat transport at 45N is
  0.64 0.09 pW between