1. Argo’s Role in Climate Science
First Argo Science Workshop
Yakult Hall, Tokyo, Japan
November 12-14, 2003
Argo’s Role in Climate Science
Kimio Hanawa
Department of Geophysics, Tohoku University
Climate Science and Physical Oceanography
cannot advance in the future
without the Argo observation system!

2. Climate Science and Physical Oceanography (Earth Science) :
“dispersive big science” ⇔ “concentrative big science”
We have to measure, observe and monitor the whole of the Earth:
here and there, everywhere
for a long time, from the past to the future
Internationally coordinated project to monitor
the whole of the world’s oceans should be established:
Argo project !

3. After AIC

4. Obs. locations
October 2000
No.= 3755/month
Locations of Argo
floats (virtual)
No.= 10000/month

5. Outcome of Argo project? Revolution in Physical Oceanography
Scientific impact:
Argo data will be used in various ways, and in the various fields.
: mixed layer distribution, heat and freshwater storage,
water mass formation, the movement, mixing and dissipation of
mode waters and intermediate waters, the subduction process ……
Actual achievements in Physical Oceanography using the Argo data
will be well beyond our present scope.

6. Qualitative description => Quantitative diagnosis
Revolution in Physical Oceanography
Dynamical diagnosis
Assimilated datasets: “Reanalysis” data
=> eddy-eddy interaction, eddy-mean flow interaction, vorticity
dissipation, meander of the currents, formation of
undercurrent … …
Qualitative description => Quantitative diagnosis
based on “reanalysis” data

7. Argo and Climate Science
Decadal to centennial climate variations: CLIVAR-DecCen
Manifestation of a large scale air-sea interaction.
The ocean plays a crucial role at these time scales.
Examples:
1. Tracing of anomalous water (subduction process)
2. Closure problem of heat and freshwater budgets

8. Tracing of anomalous water0π
Tracing of anomalous water
Figure: 1st C-EOF mode of
upper ocean heat content anomaly,
one cycle ~ 40 years
1/3π
Clockwise circulation of anomalous
water => subduction process
2/3π π

9. NCEP Closure of heat budget (Freshwater budget) SOC
Annual mean surface heat flux
NCEP
Closure of heat budget
(Freshwater budget)
Components:
1. Advection of heat,
2. Surface flux,
3. Temporal change rate
of heat storage
PX-40
PX-37
PX-44
PX-10
SOC
Argo data can provide
information of temporal
change rates of heat and
freshwater storage.

10. Impact on society and benefit to society
Argo system is a core of WOW (World Ocean Watch)! 
WWW (World Weather Watch) in the meteorological field
1. Ocean weather map
2. Prediction of the future ocean state
3. Improvement of prediction ability of long-term weather forecast

11. Weak points of Argo observation system
To complement and overcome shortcomings and weak points,
we have to adopt
other observation techniques, platforms, tools, and systems!
Areas in strong currents (western boundary currents), fronts, , ,
Stain of salinity sensor (measurement accuracy), , ,
Uncontrollable positioning, , ,

12. Thank you for your kind attention !
We hope that, more and more,
new countries and new people will get aboard the Argo ship.
The present Argonauts will give all newcomers
a warm welcome!
Thank you for your kind attention !