Theme 2: Regional Ocean Influences

1
Theme 2 Regional Ocean Influences

• Western boundary currents
• Marginal seas and exchanges with open ocean
• Atmosphere/Ocean interaction impact on local and
  far field climate
• Equatorial connection between Pacific and Indian
  Oceans

• The WEP is the hatchery for ENSO
• Scale interactions
• Representation of regional processes in global
  models

2
Sea of Okhotsk Yaremchuk, Mitsudera (Hokkaido),
Regional studies
South China Sea and Throughflow Qu, Yaremchuk, Yu
Exchange through Luzon Strait Yarumchuk, Qu, Yu
Indian Ocean Tracer transport, freshwater
constraints, O2 min Jensen, Yaremchuk, Yu, Aiki,
et al
Western equatorial Pacific and LLWBCs Richards,
Qu, Natarov, Kashino (J), Sasaki (ES)
ITF and its relation to variability of Indian and
Pacific Oceans McCreary, Potemra and Schneider
SE Indian Ocean heat budget and mixed layer Qu,
Masumoto(UT), Sasaki (ES)
Outflow of ITF Yu, Potemra
Banda Sea Kida
3
Circulation induced by throughflow
LCS ?d, n 1 mode
McCreary, Miyama (FRCGC), et al
4
Circulation induced by throughflow
There is a westward and equatorward surface
(eastward and poleward subsurface) geostrophic
flow across PO interior
The general structure of circulation, upwelling
and downwelling is a robust feature, but details
of are strongly dependent on the imposed mixing.
There is anomalous upwelling caused by the ITF in
the Pacific wherever ?d is negative.
Details of the exchange (pathways, vertical
structure, mixing) depend on geometry and wind
forcing.
McCreary, Miyama (FRCGC), et al
5
South China Sea throughflow and its impact on the
Indonesian throughflow
1. The SCSTF is a heat and freshwater conveyor,
transferring up to 0.1-0.2 PW of heat and 0.1 Sv
of freshwater from the SCS into the tropical
Indo-Pacific Ocean. 2. The SCSTF impacts the
SCS heat content. In response, the SCS acts as
a heat capacitor, storing heat in certain years
and releasing it in others. 3. The SCSTF impacts
the Indonesian throughflow. In response, the ITF
heat transport is significantly (by up to 47)
reduced. Thus, the SCS is likely to play an
active role in climate variability.
Water entering the South China Sea through Luzon
Strait is lower in temperature and higher in
salinity (blue) than water leaving it through
Karimata, Mindoro, and Taiwan Strait (red).
6
Retrieving the South China Sea throughflow from
T/S climatologies
Karimata transport 1.5-3 times less than
diagnosed by direct simulations
T/S in South China Sea
Topography in Karimata St.
7
Varying currents in the Western Equatorial Pacific
10 N
Eq
1994
2004
NECC
October 1999
October 2002
Analysis of OFES
8
Zonal current along 138 E
OFES
Obs (Kashino)
0
Sep 2001
400
Eq
10N
June 2004
9
CCSM
OFES
El Niño
La Niña
10
Lateral mixing interleaving
U
Salinity
Kashino
Model
V
Tracer
Natarov and Richards (2007)
11
Western equatorial Pacific future activities

• Use of regional models to study ocean/atmosphere
  couplings
• Analysis of OFES, CFES, SINTEX-F experiments
• Use of TAO/TRITON, Argo, Satellite data
• Participation in R/V Mirai cruise to study mixing
  in the thermocline
• Use of Earth Simulator for mixing experiments
• Major field programs NPOCE, PACWIN, SPICE

12
(No Transcript)
13
ENSO influence on the ITF
Estimates of ITF transport (8-month running-mean
filtered) are shown above in comparison to an
ENSO index. The mediocre correlation between ITF
transport and ENSO can be explained by variations
in ITF with depth.
The figure on the right is a correlation of ITF
transport (from SODA) in the upper 800m and MEI,
and it shows how the peak correlation is at
depth ITF variability at this depth originates
in the Pacific.
(Potemra and Schneider)
14
Initialization of regional OGCMs in open boundary
domains using the 3dVAR technique
15
NEC
NECC
MC
SEC
NGCC
SECC
SEC
3yr average near surface currents from 1/10
degree POP
16
SPICE
17
Marine Ecosystem
Chlorophyll (phytoplankton)
Krill
Tuna
18
IPRC Activities on the Marine Ecosystem
Phytoplankton
SST
?SST caused by bio
2oC
Biofeedback on SST (Timmermann)
Impact of stirring and mixing (Richards)
19
Future ecosystem modeling work

• Use of regional models (e.g. iROAM) with imbedded
  ecosystem model
• Biofeedbacks
• Eastern Tropical Pacific
• Arabian Sea oxygen minimum zone