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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.
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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 • In ORCA05 some problems in the tropical pacific: • no Tsuchiya Jets • EUC too deep • transport too high better representation with higher resolution? • 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)
COADS obs. ORCA05 ORCA025 Introduction SST STCs Zonal Currents NGCU Conclusions Nino3 SST
35/35 45/40 30/20 30°S 20°S 10°S Eq. 10°N 20°N 30°N Introduction SST STCs Zonal Currents NGCU Conclusions Meridional Overturning Stream Function 20/15 Sv ORCA025: KAB001 G70
Introduction SST STCs Zonal Currents NGCU Conclusions STC Strength explaination for different trends ??? ORCA05 KAB001 G70
Introduction SST STCs Zonal Currents NGCU Conclusions EUC: mean equatorial zonal velocity 0.9 0.9 ORCA05 ORCA025
nSEC nSEC cSEC cSEC NEC NEC NECC NECC EUC EUC NSCC SSCC EIC EIC Introduction SST STCs Zonal Currents NGCU Conclusions Mean zonal velocity at 155°W ORCA05 ORCA025 Tsuchiya Jets (NSCC, SSCC) in ORCA025
10°N 5°N NSCC EUC Eq. SSCC 5°S 10°S 165°E 155°W 110°W Introduction SST STCs Zonal Currents NGCU Conclusions Tsuchiya Jets eastward velocities averaged over 26.0< s <27.0
Introduction SST STCs Zonal Currents NGCU Conclusions Mean zonal velocity at 155°W 0.85 m/s 0.80 m/s 1991-2000 KAB001 G70
Introduction SST STCs Zonal Currents NGCU Conclusions mean EUC Transport in density range 22.5<s<26.0
Introduction SST STCs Zonal Currents NGCU Conclusions EUC Transport variability annual cycle KAB001 KAB002 G70 at 155°W, in density range 22.5<s<26.0 KAB001 G70
Introduction SST STCs Zonal Currents NGCU Conclusions Mean velocity in 150m depth
Introduction SST STCs Zonal Currents NGCU Conclusions 7°S section 0.1 0.35 0.4 ORCA2 ORCA05 ORCA025
ORCA2 ORCA05 ORCA025 Introduction SST STCs Zonal Currents NGCU Conclusions Transport transport variability • mean transport • (24.0 <s< 26.7) • 5°S to 10°S average: • ORCA2: • ~ 13 Sv • ORCA05: • ~ 20 Sv • ORCA025: • ~20 Sv
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
KAB001 KAB002
ORCA05 (KAB042) ORCA025 (KAB001) ORCA025 (KAB002) ORCA025 (G70)