TROPICAL -

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TROPICAL -
- EXTRATROPICAL
CONNECTIONS
INCLUDING
ENSO
MARK A. CANE LAMONT-DOHERTY EARTH OBSERVATORY
OF COLUMBIA UNIVERSITY PALISADES, NY 10964
PAUL GOODMAN AND WILCO HAZELEGER
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Which way and where from?   From the Tropics to
the Globe   To the Equatorial Ocean from the
Extratropics Subtropics Tropics What can
change equatorial SST?   How? Waves Adjustment
or Advection ?v T?, v??T   On what time
scales?   Centennial, Millennial and
beyond Interannual (ENSO) Decadal Pacific
(PDO) Atlantic (NAO)
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Poleward shift
Equatorward shift
r .60 r .76 with a 5-year lowpass (sig.
99)
Courtesy of Clara Deser
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Advection of anomalous Temperaturev T?

• Gu and Philander Science 1997
• Latif and Barnett Science 1994
• Deser et al J. Climate 1996
• Zhang et al Science 1998

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Hazeleger et al JGR 2001
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Decadal anomalies of the depth of the s0 25.5
isopycnal zonally averaged in the shaded region ?
? From a coupled model
From Schneider et al, GRL 1999
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Change in overturning stream function with added
cooling due to storms
Hazeleger et al., JPO,2001
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Anomalous Advection of mean Temperature
v'T
the Subtropical Cell

• McCreary and Lu JPO 1994
• Liu Liu, Philander and Pacanowski JPO 1994
• FIne, Peterson and Ostlund JPO 1987
• Johnson and McPhaden JPO 1999
• McPhaden and Zhang Nature 2002

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Meridional Stream Function OCCAM model
Eulerian Lagrangian L-E
z
s
Hazeleger et al., GRL, 2001
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Potential Vorticity
McPhaden and Zhang Nature, 2002
Zhang et al., JPO submitted. (See Rizzoli et
al., DOA 2000 for a model version)
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Interior communication window identified from
the virtual streamfunction (in Sv)
Huang and Wang, JPO, 2001
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8S
8N
Mass Flux Accumulated down
Johnson and McPhaden, JPO, 1999
Goodman et al, 2002 To appear
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Volume Ventilated (103 m3/s)
Goodman et al., 2002
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Time Between Subduction and the EUC (years)
Goodman et al., 2002 to appear
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10N
3.5
0.6
Eq
8.3
1.8
5S
2.0
13S
6.3
3.8
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McPhaden and Zhang Nature, 2002
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McPhaden and Zhang, Nature, 2002
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Heat Transports in a model Indo-Pacific Ocean
Hezeleger et al JPO submitted
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AdjustmentWave Processes

• Rossby JMR 1937
• Cane and Sarachik JMR 1977, 1981JPO 1983
• Johnson and Marshall JPO, JGR 2002

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Temperature along the equator
Halpern, 1980
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H
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So, a wind anomaly scale of 10 increases the
temperature of upwelled water by 1K.With w
1m/day, DQ 50W/m2A change in the STC of 0.1
PW (estimated from the same 0.02 N/m2 spread
from 10S to 10N over 1/3 of the width of the
Pacific is 10W/m2
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Decadal anomalies of the depth of the s0 25.5
isopycnal zonally averaged in the shaded region ?
? From a coupled model
From Schneider et al, GRL 1999
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PC timeseries
Decadal Pattern
Forcing region
12N/S
10N/S
7N/S
5N/S
Karspeck and Cane, JPO 2002
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McPhaden and Zhang Nature, 2002
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Discussion

• The longer the period the more poleward the
  reach.
• Why is there decadal variability?
• Is there anything special about decadal?
• Decadal Variability is
• most likely generated in the tropics
• the southern hemispere is the next place to go
• adjustment is more important than advection

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• It would be nice to quantify decadal variations
  in heat budgets.
• And even nicer to have a usable theory
• for what sets and what can change
• ocean stratification.
• But even these wont tell us the
• sources of decadal variability

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It is a coupled systemocean ? atmosphere
at least in the tropics