Thoughts on Northwestern Pacific Ocean Circulation Experiment NPOCE Dunxin Hu Institute of Oceanolog

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Thoughts on Northwestern Pacific Ocean
Circulation Experiment (NPOCE)Dunxin Hu
Institute of Oceanology Chinese
Academy of Sciences

• At CLIVAR workshop on WTP, 26 Nov.
  2007,Guangzhou China

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Warm pool heat source for atmospheric
circulation, in formation of which ocean
circulation plays essential role
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• Outline
• 1. Brief review on field experiment in the
  northwestern Pacific Ocean
• Remaining problems to be understood and solved
• NPOCE workshop An international joint program
  needed (thought for long and more realistic now)

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• Brief review on field experiment in NWP
• CSK(1960-70s)
• TOGA(1985-1994)/WOCE(1990-1997)
• (WEPOCS1985-88, PRC-US1985-1990,
• CAS1985-1990, TOCS1995-99
• NGCUC and MUC were revealed and so
  forth
• Calm period for 10-15 years (since early1990s)
• Discussions between scientists in the last 10
  years (IOCAS, IPRC, PMEL, UH, U. Sydney, UW,
  WHOI, etc.)

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• Questions
• 1. What we have known?
• 2. What we do not know?
• 3. How to solve the problems?

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EUC (R/V Hugh Smith, 1951 Cromwell et al. (1954)
Velocity (U) and temperature distributions along
meridional and zonal sections
u
T
Zonal section of T along the equator
Johnson et al. (2002)
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Annual mean of zonal velocities along 143ºE
section
Measurements (Johnson et al., 2002)
Mean 143E
SODA
HYCOM (Wang and Hu, 2007)
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Zonal velocities (cm/s) along 143E from Papua New
Guinea to 5N. Shaded area indicates westward flow
NGCUC
EUC
(Lindstrom et al., 1987)
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MUC
(Hu and Cui, 1989)
V component along 7.5N
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V component along 18N(cm/s)
?
U component along 130E(cm/s)
LUC
NEUC
V component along 8N(cm/s)
MUC 16Sv
Composite from 11 cruises of China-US and CAS in
1980s
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Meridional velocity (V-component) along 18N

cm/s
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?
?
NGCUC
?
EUC
(Fine et al., 1994 Lukas et al., 1996)
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1. Bifurcation of NEC?
Results not consistent!

• Bifurcation latitude
• Nitani (1972) 11-14.5N
• Toole et al. (1988, 1990) 12-13N
• Qu and Lucas (2003) 13.3N (20N at 1000m)
• Wang and Hu (2006) 13.4N
• Changes
• Qiu and Lukas (1996) northernmost in Oct and one
  year after El Niño southernmost in Feb. and La
  Niña year
• Qu and Lukas (2003) northernmost in Nov.
  southernmost in June
• Kim et al. (2004) northernmost in Sept. and El
  Niño year southernmost in May and La Niña year
• Wang and Hu (2006) northernmost in Dec. and El
  Niño year southernmost in June and La Niña year

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• 2. Origin of MUC and EUC?
• 3. Relation (connection) between those
• undercurrents, especially between MUC
• and NGCUC?
• 4. LUC to be measured?
• 5. Transports through Luzon Strait and of
• the Kuroshio at its origin?

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• Subtropical subsurface waters get into EUC
  through central Pacific as well as LLWBC (MC
  NGCUC) and cause inter-decadal variability of
  ENSO. EUC water from NGCUC, MC and interior of
  the Pacific Ocean (McCreary and Lu,
  1994 Gu and Philander, 1997 Lu et al., 1997)

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Water sources of EUC?
1.3Sv
Mindoro St.
From MC
8.2Sv
20.3Sv
EUC
2.2Sv
8.6Sv
NGCUC
From IO
Horizontal flow at 200m (annual mean)from HYCOM
Hu and Wang, 2007
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EUC water sources along 143E
Hu and Wang (2007)
EUC water sources 1. NGCUC 8.6Sv 2. MC
8.2Sv 3. Indian Ocean 2.2Sv 4. Mindoro St
1.3Sv Total 20.3Sv
NGCUC
EUC
from NGCUC
from MC from Indian O.
from Mindoro St.
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Water source of MUC?
Water from IO into MUC
Hu and Wang, 2007
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Water source of MUC?
MUC water mainly from IO
From IO
Hu and Wang, 2007
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Water source of MUC?
MUC
Water from IO into MUC
Hu and Wang, 2007
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Water source of MUC?
MUC
Water from IO into MUC
Hu and Wang, 2007
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Water source of MUC?
MUC
Water from IO into MUC
Hu and Wang, 2007
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• After mutual visits and discussions in the last
  more than 10 years, scientists from various
  countries showed strong desire to go back to the
  western Pacific and work there again. As a result
  NPOCE workshop was held on 17-18 May 2007 in
  Qingdao, China.

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• Agreed An international joint program is needed
  and possible now.
• Present status
• Some Chinese funds available and hope more to
  come (two 973 projects funded, a major NSFC
  project under discussion).
• Suggest to get funds for the southern part of
  NPOCE (another Chinese 973 project or from other
  nations?).

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NEUC
Sketch of ocean circulation in the northwestern
Pacific Ocean
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Design of the Northwestern Pacific Ocean
Circulation Experiment (NPOCE)
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Chinese 973 Subtropical gyre variability and its
impact on seas surrounding China (2007 -2011)
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973 Project (2006-2011)Ocean-Atmosphere
Interaction in Asia and Indian-Pacific Ocean
(AIPO) Confluent Region and Its Impact on the
Short-Term Climate Variation in China
Asia
W. Pacific
Indian O.
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Schematic observation plan of air-sea interaction
in the AIPO Region
Western Pacific Ocean
Kuroshio
SCS
NEC
NECC
ITF
SEC
Indian Ocean
SJC
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973 project (2007-2012)Title Variability of
Subtropical Gyre in the North Pacific Ocean and
its Impacts on Dynamic Environment of the
Marginal Seas
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Observation plan of 973 projects
KC
CTC section Bottom mounted ADCP Subsurface
mooring Other projects PN Sections (Japan)
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(1) Experiment in the northern part of NPOCE east
of Luzon and Taiwan will start from 2007/2008
based on two Chinese 973 projects AIPO
(2006-2011) and NSG (2007-2012) with US
collaboration.
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2)Experiment in the southern part of NPOCE
between Mindanao and New Guinea, where MC and SEC
get in, and ITF and NECC leave from. Circulation
there is very complex and poorly understood.
This is one of the hot spots scientists have
been attracted to. Scientists intend to get funds
for, after the NPOCE workshop held in May 2007
Qingdao China.
A conference on western Pacific circulation and
its role in climate is planned to be held in 2008
Key facilities Mooring, Argo floats, Gliders.
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North NPOCE Two Chinese 973 projects (2006-2011)
South NPOCE ???
(NSFC or ohters?)
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NPOCE SPICE PACSWIN would make the whole
western Pacific Ocean one of the CLIVAR Pacific
Panel important targets
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????! THANK YOU!
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