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Pacific (Sub) tropical circulation in ORCA025 and ORCA05. DRAKKAR Meeting 2007 Joke Lübbecke. Introduction SST STCs Zonal Currents NGCU Conclusions. Schott et al., 2004. nSEC. sSEC. NEC. NECC. EUC. Introduction SST STCs Zonal Currents NGCU Conclusions. - PowerPoint PPT Presentation
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Pacific (Sub) tropical circulation in ORCA025 and
ORCA05
DRAKKAR Meeting 2007Joke Lübbecke
Introduction SST STCs Zonal Currents NGCU Conclusions
Schott et al., 2004
NEC
EUC
nSECsSEC
NECC
o In ORCA05 some problems in the tropical pacific:• no Tsuchiya Jets• EUC too deep• transport too high
better representationwith higher resolution?
Introduction SST STCs Zonal Currents NGCU Conclusions
o Differences between the ORCA025 experiments:• KAB001 (CORE forcing, weak 3-dim restoring in high lat.)• KAB002 (CORE forcing, strong surface restoring)• G70 (ERA-40, strong surface restoring)
Nino3 SST
COADS obs.ORCA05ORCA025
Introduction SST STCs Zonal Currents NGCU Conclusions
Meridional Overturning Stream Function
ORCA025:KAB001G70
20/15 Sv30/2035/35 45/40
Eq.10°S 10°N20°S 20°N30°S 30°N
Introduction SST STCs Zonal Currents NGCU Conclusions
STC Strength
ORCA05KAB001G70
Introduction SST STCs Zonal Currents NGCU Conclusions
explaination for different trends ???
ORCA05 ORCA025
EUC: mean equatorial zonal velocity
0.9 0.9
Introduction SST STCs Zonal Currents NGCU Conclusions
ORCA05 ORCA025
Mean zonal velocity at 155°W
EUC
nSECcSEC
NECNECC
EIC
EUC
nSECcSEC
NECCNEC
EIC
NSCC
SSCC
Tsuchiya Jets (NSCC, SSCC) in ORCA025
Introduction SST STCs Zonal Currents NGCU Conclusions
Introduction SST STCs Zonal Currents NGCU Conclusions
Tsuchiya Jets
eastward velocities averaged over 26.0< <27.0
NSCC
EUC
SSCC
Eq.
5°N
5°S
10°S
10°N
155°W165°E 110°W
Mean zonal velocity at 155°W
KAB001
G70
Introduction SST STCs Zonal Currents NGCU Conclusions
0.80 m/s0.85 m/s
1991-2000
mean EUC Transport
Introduction SST STCs Zonal Currents NGCU Conclusions
Experiment 165°E 155°W 110°W
ORCA05
KAB042
34 Sv 46 Sv 28 Sv
ORCA025
KAB001
32 Sv 38 Sv 23 Sv
ORCA025
G70
22 Sv 27 Sv 18 Sv
Johnson et al., 2002
17 Sv 35 Sv 26 Sv
in density range 22.5<<26.0
EUC Transport variability
Introduction SST STCs Zonal Currents NGCU Conclusions
at 155°W,in density range22.5<<26.0KAB001
G70
annual cycle
KAB001KAB002G70
Introduction SST STCs Zonal Currents NGCU Conclusions
Mean velocity in 150m depth
7°S section
ORCA2 ORCA05 ORCA025
0.35
0.4
0.1
Introduction SST STCs Zonal Currents NGCU Conclusions
Transport
transport variability mean transport
(24.0 << 26.7)5°S to 10°S average:
• ORCA2: ~ 13 Sv• ORCA05: ~ 20 Sv• ORCA025: ~20 Sv
ORCA2ORCA05ORCA025
Introduction SST STCs Zonal Currents NGCU Conclusions
Introduction SST STCs Zonal Currents NGCU Conclusions
• improvements with ORCA025: Tsuchiya Jets present EUC extension not that deep more realistic EUC transport representation of western boundary current
• KAB001 compared to G70: structure of zonal currents and OT similar all wind driven features weaker in G70 EUC transport variability in phase with offset
• open question: different STC trends: ORCA05 > G70 > KAB001
KAB001KAB002
ORCA05 (KAB042)ORCA025 (KAB001)ORCA025 (KAB002)ORCA025 (G70)