tropical -

TROPICAL - - EXTRATROPICAL

CONNECTIONS

INCLUDING

MARK A. CANELAMONT-DOHERTY EARTH OBSERVATORY OF COLUMBIA UNIVERSITYPALISADES, NY 10964+ PAUL GOODMAN AND WILCO HAZELEGER

ENSO

With Thanks To:

Tony Busalacchi Roger LukasRui Xin Huang Jay McCrearyGreg Johnson Mike McPhadenMojib Latif Mosami NonakaZengyu Liu Paola Rizzoli

Which way and where from? From the Tropics to the Globe To the Equatorial Ocean from the Extratropics

SubtropicsTropics

What can change equatorial SST? How?

Waves [Adjustment] or Advection: v T, vT

 On what time scales?  Centennial, Millennial and beyond

Interannual (ENSO)Decadal: Pacific (PDO)

Atlantic (NAO)

Polewardshift

Equatorwardshift

Courtesy of Clara Deser

r = .60;r = .76 with a 5-year lowpass (sig.= 99%)

Advection of anomalous Temperature

v T

Gu and Philander Science 1997

Latif and Barnett Science 1994

Deser et al J. Climate 1996

Zhang et al Science 1998

Hazeleger et al JGR 2001

Decadal anomalies of the depth of the 0 = 25.5 isopycnal zonally averaged in the shaded region

From Schneider et al, GRL 1999

From a coupled model

Hazeleger et al., JPO,2001

Change in overturning stream function with added cooling due to storms

Anomalous Advection of mean Temperature

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

the Subtropical Cell

v'T

Meridional Stream FunctionOCCAM model

Eulerian Lagrangian L-E

Hazeleger et al., GRL, 2001

z

McPhaden and ZhangNature, 2002

Potential Vorticity

Zhang et al., JPO submitted.

(See Rizzoli et al., DOA 2000 for a model version)

Interior communication window identified from the virtual streamfunction (in Sv)

Huang and Wang, JPO, 2001

Johnson and McPhaden, JPO, 1999

8°S

8°N

Mass FluxAccumulated

down

Goodman et al, 2002 To appear

Goodman et al., 2002

Volume Ventilated (103 m3/s)

Goodman et al., 2002 to appear

Time Between Subduction and the EUC (years)

10N

Eq

5S

13S6.3

3.8

1.88.3

3.5 0.6

2.0

McPhaden and Zhang Nature, 2002

McPhaden and Zhang, Nature, 2002

Heat Transports in a model Indo-Pacific Ocean

Hezeleger et al JPO submitted

AdjustmentWave Processes

Rossby JMR 1937

Cane and Sarachik JMR 1977, 1981;JPO 1983

Johnson and Marshall JPO, JGR 2002

Temperature along the equator

Halpern, 1980

H

So, a wind anomaly scale of ~ 10° increases the temperature of upwelled water by ~ 1°K.

With w ~ 1m/day, Q ~ 50W/m2

A change in the STC of 0.1 PW (estimated from the same 0.02 N/m2 spread from 10°S to 10°N over 1/3 of the width of the Pacific is ~10W/m2

Decadal anomalies of the depth of the 0 = 25.5 isopycnal zonally averaged in the shaded region

From Schneider et al, GRL 1999

From a coupled model

PC timeseries Decadal PatternForcingregion

12°N/S

10°N/S

7°N/S

5°N/S

Karspeck and Cane, JPO 2002

McPhaden and Zhang Nature, 2002

DiscussionThe 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

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 won’t tell us the

sources of decadal variability:

It is a coupled system*

ocean atmosphere

*at least in the tropics