LB01, Lamon bay

1
LB01, Lamon bay
LB01, Bifurcation track
2
vertical black bar core X XBT V vertical net
tows O oblique net tows Red triangle
TRBM Vertical red bar line moorings
3
S-max NPsubtropical
Port Irene bay
thermocline
Port Irene bay
S-min NPIW
Pressure db meters
Polillo depression
Polillo depression
Polillo depression O2-min
100-200 m frequent O2-min
Port Irene bay
Lower thermocline O2-min
All CTD
Stratification LB01, LB02, LB02 (NE)
4
NEC S-max
Kuroshio S-max
LB1
LB02 thermohaline pattern (red and cyan) in Lamon
Bay reflects dominance of North Equatorial
Current (NEC) water whereas LB01 (black)
reflects Kuroshio recirculation gyre regime. The
cyan LB02 stations, with Kuroshio T/S, are in the
northeastern part of the station array. The LB02
green stations are within the embayment of Port
Irene. The LB02 nascent Kuroshio is composed of
NEC T/S
LB2
Polillo channel
All CTD stations 1-78
LB1
NEC S-min
NPIW
LB2
Kuroshio S-min
5
CTD 1-78
NEC, S-max
Polillo channel
Kuroshio
Black LB0-1 Red LB02 Cyan LB02 Green LB02
LB1
LB2
NPIW
Kuroshio
6
NEC
Kuroshio
Polillo and Port Irene Bay
All CTD stations 1-78
NEC
Kuroshio
LB02 dominate NEC signature, except in NE part
of stations array
7
LB01
LB02
Focus on Lamon Bay south of 17.5N LB01
Black LB02 Red
LB01
LB02
Message the time period (april/may 2012) of
LB02 displays greater presence tropical North
Equatorial Current water than the LB01 period
(May/June, 2011), why?
8
(No Transcript)
9
(No Transcript)
10
18.35N
western boundary
NEC S-max
western boundary
North Pacific S-min Kuroshio
looking north
looking south
17.12N
NEC S-max
western boundary
western boundary
looking north
looking north
11
16.50N
western boundary
NEC S-max
western boundary
North Pacific S-min Kuroshio
looking north
looking south
124.25E
NEC S-max
North Pacific S-max S-min Kuroshio
Southern boundary
Southern boundary
looking west
looking west
12
Lamon Bay cruise 1, 23-55 m current vectors,
Lamon Bay cruise 2, 23-55 m current vectors, as
of 8 May 2012
Kuroshio recirculation gyre
Nascent Kuroshio
Nascent Kuroshio
SSS color coded
Kuroshio recirculation gyre
anticyclone dipole
anticyclonic dipole
Lamon bifurcation
Lamon bifurcation
cyclonic dipole
cyclonic dipole
Weak NEC signal
Kuroshio feeder current
Polillo current
Strong NEC source
Polillo current
SSS color coded
Solid arrows denote stronger flow, with clear T/S
source water signal. LB02 Kuroshio recirculation
gyre retreats northward to be replaced by NEC
waters LB01 shows southward penetration of the
Kuroshio recirculation gyre, with reduced NEC
water vectors not to same scale
13
(No Transcript)
14
15.3 Sv
10 Sv, LB01
-5.5 Sv
D2.6 Sv
12.4 Sv
11 Sv, LB01
D-2.2 Sv
-10.2 Sv
LB02 Transports 15?, upper 300 m
15
Bifurcation 13 - 14 N
North Equatorial Current
Bifurcation 10 - 11 N
North Equatorial Current
stronger Mindanao Current
weaker Mindanao Current
NEC bifurcation, late May 2011, during R/V
Revelle transit to south to avoid tyhpoon Songda
NEC bifurcation, April 2012, During R/V Revelle
transit, Freemantle to Legaspi.
16
Weaker Kuroshio
April 2012 La Niña
May 2011 Neutral
Stronger Kuroshio, enriched in Equatorial water
Kuroshio
Kuroshio
Luzon Strait throughflow
Weak or 0 Luzon Strait throughflow

Weak South China Sea throughflow
South China Sea throughflow
bifurcation
North Equatorial Current
North Equatorial Current
bifurcation
Mindanao
Mindanao
Stronger Makassar ITF
Weaker Makassar ITF
For supporting information see ppt slide Notes
page see next slide for relation to Aviso
17
Possible Implications of an ENSO bifurcation
dependent Kuroshio source During La Niña
there is increased injection of  NEC tropical
Pacific water into the subtropical North Pacific
during El Niño the subtropical North Pacific is
more 'isolated' from the NEC.   The NEC
enhanced Kuroshio transport during La Niña, leads
to greater northward heat flux into the North
Pacific reduces western pacific warm pool
volume. The NEC injection into the subtropical
regime, on climatic average (the integrated La
Niña/El Niño phases), balances the loss of North
Pacific water through the Bering Straits (1 Sv)
and through Luzon Strait (3 Sv) into the South
China Sea (that most likely advects into the
Indian Ocean as part of the Indonesia
Throughflow). During El Niño the Kuroshio
recirculation gyre reaches into Lamon Bay, to can
feed the westward leakage into the South China
Sea,  (Luzon Strait westward transport is
increased during El Niño, HYCOM, Hurbert et al
2011). In this way the Kuroshio recirculation
gyre exports the accumulated NEC injected during
the previous La Niña phases. More...  effect
on ecosystems, linkage with PDO, impact on ITF,
WPWP ...
ITF comment During El Niño the SCS throughflow
via Sibutu Passage blocks Mindanao surface layer
leakage to Makassar Strait, which lowers the
Makassar net transport, counteracting thegreater
Mindanao transport associated with the northern
bifurcation position.
18
(No Transcript)
19
Dt 4C _at_ 200 m 18C isotherm Dz _at_ 70 m
Deeper isotherms
Kuroshio
Shallower isotherms