CLIVAR Pacific panel

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CLIVAR Pacific panel
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Main Issues

• ENSO (and related aspects)
• Observational requirements
• Metrics (societal and scientific)
• SPCZ
• Eastern Pacific biases (VOCALS)
• Interbasin connections
• SPICE
• Interaction with other panels

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ENSO

• Understanding and predicting ENSO
• Background state gt MJO ? ENSO
• Background state gt annual cycle ? ENSO
• Background state ? ENSO
• ENSO and stochastic forcing
• ENSO and greenhouse warming
• Decadal timescales in ENSO
• ENSO metrics (diagnostics and observations)

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ENSO sensitivity to climate change Observational
requirements

• Monitoring of SST, thermocline depth, boundary
  and interior transports
• Monitoring of Walker circulation (see Vecchi and
  Soden, Nature 2006)
• Monitoring of ENSO-MJO relationship
• Monitoring of subsurface anomalies (ARGO, TAO,
  altimeter)
• Monitoring of heat flux convergences via drifter
  data, ARGO data

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ENSO-WWB interactions,

• WWB activity modulates and is modulated by ENSO
  (Eisenman, Jin, Lengaigne)
• WWB is modulated by the annual cycle (Hendon and
  Zhang)
• Nature and Dynamics of these interactions still
  unclear
• Evidence for intensification of WWB and WWB-ENSO
  interactions (Jin et al. 2007)
• What background conditions make this interaction
  favorable?

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• East-ward propagating coupled instabilities

ENSO-WWB interactions,
WWB modulation by temperature
Eisenman et al. 2005
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ENSO-WWB interactions observational requirements

• Monitoring of zonal temperature advection
• Monitoring of MJO and warm pool heat budget
• Precise knowledge of WWB initial conditions
• Monitoring of MJO-warm pool front propagation
  (satellites) and subsurface response (TAO,
  altimetry)

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Understanding the South Pacific Convergence Zone

• Why is there a SPCZ?
• How is it connected to the ITCZ?
• How does the SPCZ interact with the MJO?
• How does the SPCZ interact with the SST
• How does the SPCZ respond to tropical and
  extratropical SST forcing on interannual to
  decadal timescales?
• What influence does the SPCZ wind convergence and
  its modulation have on southwest Pacific boundary
  currents?

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Understanding the SPCZ

• Clouds and temperatures in observations (left)
  and NCAR CCSM3 model

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Understanding the SPCZ
Figure 1 Schematic of hypothesised mechanism for
the development of convection along the SPCZ
during an MJO. Convection over Indonesia (1)
associated with the passage of a MJO leads to an
upper tropospheric anticylone (2). Poleward of
the anticyclone, there is a large PV gradient,
associated with the subtropical jet and the
tropopause (3). Equatorward advection of high''
PV air on the eastern flank of the anticylone
leads to an upper tropospheric trough (4), which
induces deep ascent to the east (5). This region
of deep ascent, to the southeast of Indonesia, is
over the SPCZ, an area susceptible to deep
convection. Hence strongly enhanced convection
can be triggered by the deep ascent and
convection develops from Indonesia into the SPCZ
(6).
Matthews et al 2000 QJR
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Understanding the SPCZ observational requirements

• Series of detailed process studies needed (a la
  TOGA-COARE) focusing on cloud formation, boundary
  layer dynamics, atmosphere-ocean interactions
• Relationship between SST, SPCZ, Rain and Salinity
  using satellite data (Aquarius,SMOS)
• Response of ocean to variations in SPCZ (ARGO,
  drifter data)
• SPCZ and subduction and mode-water formation
  (ARGO, Repeat hydrography)

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Improving model biases in the eastern tropical
Pacific, cold bias and warm bias, SPCZ bias

• Possible origin of cold bias in coupled models
  (missing ocean biology, under-representation of
  TIWs, mixing, missing diurnal cycle of
  insolation, under-representation of Galapagos
  effect, uncertainties in convective
  parameterizations)
• Possible origin of warm bias in stratus regions
  (problems with cloud parameterizations and
  cloud-aerosol interactions, missing Tsuchiya
  jets, lack of horizontal resolution,
  under-representation of eddies in AR4 CGCMs)

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Improving model biases in the eastern tropical
Pacific, cold bias and warm bias

• Clouds and temperatures in observations (left)
  and NCAR CCSM3 model

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Improving model biases in the eastern tropical
Pacific, cold bias and warm and SPCZ bias
observations needed

• Vertical chlorophyll profiles gt bio-optical
  feedbacks
• Better estimates of eddy-induced heat transports
  in the southeastern Pacific (VOCALS)
• Better observations of Tsuchiya Jets and their
  variability
• Observational estimates of TIW heat budgets
• Focused process study on SPCZ needed!

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Interbasin connections on interannual to
multidecadal timescales
AMO
A weakened MOC leads to a reduction Of the
meridional asymmetry in the eastern Tropical
Pacific, hence a weakening of The annual cycle
and an intensification of ENSO Whether the
AMO reflects variations of the AMOC is still
unclear, although modeling Results suggest a
strong influence of the AMOC on Atlantic
SST Challenge for ocean data assimilation to
Establish a closer link between observed AMO and
AMOC variability
ENSO
ACY
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Interbasin connections on interannual to
multidecadal timescales, observational
requirements

• Establish better statistical evidence for
  interbasin linkages using paleo-reconstructions
  of AMO (speleothems, drought indices), ENSO and
  annual cycle strength (corals, speleothems,
  varved lake sediments)
• Monitoring of MOC and AMO and their linkages with
  ENSO on decadal and longer timescales
• Monitoring of cross-central America moisture
  transport, stability of AMOC

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ENSO metrics

• Societal relevance, application indices
• Standard Nino X indeces
• Rainfall over Peru and Ecuador, northern
  Australia
• Wave heights along Californian Coast
• Subsurface temperature around Galapagos
• Number of tropical cyclones in western tropical
  Pacific
• Chlorophyll concentration in Nino 3, and Nino 1
  regions
• Upwelling indices in eastern equatorial Pacific,
  along the South and North American coast
• Seasonal forecasts not only of SST but also of
  primary productivity in Nino X regions
  (desirable, but not yet available)
• Coral bleaching indices from NOAAs Reef watch

• Scientific relevance, advancing our
  understanding and prediction
• Standard Nino X indeces
• Standard warm water indices (PMEL web-site)
• MJO variance index (BMRC web-site)
• Second and third order statistics (including
  spectra)
• BJ index
• Transport indices (boundary and interior
  transports)
• SST-lead-lag correlation between east and west
  SSTA
• Growth rate and variance of ENSO as a function of
  calendar month
• Composite of annual cycle strength for El Nino
  and La Nina years
• TIW variance and heat transport
• Individual heat budget terms
• Moisture transport Atlantic-Pacific in
  atmosphere, interannual variations

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Southwest PacIfic Ocean Circulation and Climate
Experiment
Goal Observe, Model, and understand the role of
the SW Pac Ocean in the -Large scale decadal
climate modulation-ENSO -Tasman Sea
area -Generation of local climate signatures
A. Ganachaud, W. Kessler, S. Wijffels, K.
Ridgway, W. Cai, N. Holbrook, M. Bowen, P.
Sutton, B. Qiu, A. Timmermann, D. Roemmich, J.
Sprintall, S. Cravatte, L. Gourdeau, T. Aung
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The Southwest Pacific Ocean
SPCZ
SPCZ
A
A
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Thermocline water currents
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SPICE Field Experiment Overview
Outset for a large scale field experiment
3-North Coral Sea Pilot study
A-Existing large scale programsB-Pilot
studiesC-Sustained observations
1-Monitoring inflow and bifurcation
2-EAC variability monitoring
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SPICEwww.ird.nc/UR65/SPICE

• Implementation plan in progressBased on existing
  infrastructures and research groupsNeed for a
  process study in the SPCZ

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Local Climate and environment influences
Ocean and climate fluctuations have strong,
measurable impacts on biodiversity freshwater
resources, health and tropical cyclones Pacific
Islands are highly sensitive to the oceanic
environment fragile ecosystems, low-lying
populated areas, isolation, Need for
implementing the link between large-scale
oceanography, coastal island oceanography, and
impacts on climate and environment Work with
existing structures (PI-GOOS/SOPAC/START-Oceania)
UPWELLING IN NOUMEA
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Workshop on Western Tropical Pacific Hatchery
for ENSO and Global TeleconnectionsGuangzhou
CHINA, 26-28 November 2007

• To address key science questions, such as
• - does the South China Sea play an important
  role in the climate system or is it merely
  responding to Pacific/Indian forcing?
• - How important is the South China Sea
  Throughflow in draining heat out of the Pacific?
• - What triggered the 2006/07 El Nino event?
• - What were the global impacts of the
  2006/2007 El Nino?
• - How good was the forecast skill of the
  2006/2007 El Nino?
• - How does the longterm Indian ocean warming
  affect the global climate system (including
  ENSO)?
• - What is the origin of the longterm Indian
  ocean warming?
• -How does the warm pool respond to
  anthropogenic climate change (atmospheric versus
  oceanic feedbacks)?
• Further engage the Chinese oceanographic and
  climate research community in CLIVAR
• Link the Chinese observational activities to
  other international field programs (such as
  SPICE, NPOCE and PACSWIN)
• Seek international coordination in terms of field
  experiment timing and infrastructure (sharing
  ships, common XBT lines, ...), large scale
  modeling projects, ocean, atmosphere and coupled.

http//www.clivar.org/organization/pacific/meeting
s/pacific_workshop.php