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With Thanks To: Tony Busalacchi Roger Lukas Rui Xin Huang Jay McCreary Greg Johnson Mike McPhaden Mojib Latif Mosami Nonaka Zengyu Liu Paola Rizzoli. TROPICAL -.
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With Thanks To: Tony Busalacchi Roger Lukas Rui Xin Huang Jay McCreary Greg Johnson Mike McPhaden Mojib Latif Mosami Nonaka Zengyu Liu Paola Rizzoli TROPICAL - - EXTRATROPICAL CONNECTIONS INCLUDING ENSO MARK A. CANE LAMONT-DOHERTY EARTH OBSERVATORY OF COLUMBIA UNIVERSITY PALISADES, NY 10964 + PAUL GOODMAN AND WILCO HAZELEGER
Which way and where from? From theTropicsto the Globe To theEquatorial Oceanfrom the Extratropics Subtropics Tropics 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)
Poleward shift Equatorward shift r = .60; r = .76 with a 5-year lowpass (sig.= 99%) Courtesy of Clara Deser
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
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
Change in overturning stream function with added cooling due to storms Hazeleger et al., JPO,2001
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
Meridional Stream Function OCCAM model Eulerian Lagrangian L-E z s Hazeleger et al., GRL, 2001
Potential Vorticity McPhaden and Zhang Nature, 2002 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
8°S 8°N Mass Flux Accumulated down Johnson and McPhaden, JPO, 1999 Goodman et al, 2002 To appear
Volume Ventilated (103 m3/s) Goodman et al., 2002
Time Between Subduction and the EUC (years) Goodman et al., 2002 to appear
10N 3.5 0.6 Eq 8.3 1.8 5S 2.0 13S 6.3 3.8
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
So, a wind anomaly scale of ~ 10° increases the temperature of upwelled water by ~ 1°K.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 10°S to 10°N over 1/3 of the width of the Pacific is ~10W/m2
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
PC timeseries Decadal Pattern Forcing region 12°N/S 10°N/S 7°N/S 5°N/S Karspeck and Cane, JPO 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