TROPICAL -- EXTRATROPICAL CONNECTIONS INCLUDING MARK A. CANE LAMONT-DOHERTY EARTH OBSERVATORY OF COLUMBIA UNIVERSITY PALISADES, NY PAUL GOODMAN AND WILCO HAZELEGER ENSO With Thanks To: Tony Busalacchi Roger Lukas Rui Xin Huang Jay McCreary Greg Johnson Mike McPhaden Mojib Latif Mosami Nonaka Zengyu Liu Paola Rizzoli

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)

Poleward shift Equatorward shift 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'Tv'T

Meridional Stream Function OCCAM model Eulerian Lagrangian L-E Hazeleger et al., GRL, 2001 z 

McPhaden and Zhang Nature, 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, °S 8°N Mass Flux Accumulated down Goodman et al, 2002 To appear

Goodman et al., 2002 Volume Ventilated (10 3 m 3 /s)

Goodman et al., 2002 to appear Time Between Subduction and the EUC (years)

10N Eq 5S 13S

McPhaden and Zhang Nature, 2002

McPhaden and Zhang, Nature, 2002

Heat Transports in a model Indo-Pacific Ocean Hezeleger et al JPO submitted

Adjustment Wave 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/m 2 A change in the STC of 0.1 PW (estimated from the same 0.02 N/m 2 spread from 10°S to 10°N over 1/3 of the width of the Pacific is ~10W/m 2

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 timeseriesDecadal Pattern Forcing region 12°N/S 10°N/S 7°N/S 5°N/S Karspeck and Cane, JPO 2002

McPhaden and Zhang Nature, 2002

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

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