Future directions for joint AAMP, Pacific Panel activities

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Future directions for joint AAMP, Pacific Panel
activities

• Scientific challenges
• Observational Programs
• Cross-cutting issues
• With help from
• W. Cai, D. Wang, A. Clement,
• A. Ganachaud

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Intraseasonal Oscillations
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Intraseasonal oscillations
Figure 1 The life cycle of the Madden-Julian
oscillation. Each map is separated by 3 days.
The blue shading show regions of enhanced
rain- fall (negative OLR anomalies) and the red
shading shows regions of reduced rainfall
(positive OLR anomalies). The regions of
anomalous rainfall can be seen to move eastward
over the tropical Indian Ocean - western Pacific
through the MJO life cycle.
Matthews QJR (2000)
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Intraseasonal oscillations and ENSO

• ENSO-WWB interactions play an important
• role G1BT
• In determining ENSO amplitude
• ENSO predictability
• ENSO skewness
• ENSO instability
• ENSO sensitivity to climate change

Jin, Lin, Timmermann, Zhao, 2007, GRL
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MJO and 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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Monsoon and ENSO pace-maked by the North
Atlantic?
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MOC and ENSO
Timmermann et al. J. Climate 2006, accepted
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MOC and ENSO
Timmermann et al. J. Climate 2006, accepted
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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MOC and Asian monsoon
Regression of modeled LF JJAS Rainfall Anomaly on
modeled AMO Index
From Zhang and Delworth 2006
Modeled AMO Index
Regression of observed LF JJAS Rainfall Anomaly
(CRU data) on observed AMO Index
Observed AMO Index
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AMO and Indian monsoon and ENSO
MOC weakening -gt northern hemisphere cools -gt
weakening of summer monsoon -gt weakening of
annual cycle activity in the eastern tropical
Pacific ???
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AMO and Indian monsoon and ENSO
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AMO natural versus aerosols
From Wenju Cai
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Predictability of the AMO, AMOC
ECHAM3-LSG
lowpass

• MOC
• Skill up to 20 years
• Predicting damped persistence

Groetzner, Latif, Timmermann, Voss 1999
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Challenges

• Establish link between AMO and multidecadal
  variability of monsoon and ENSO in different
  CGCMs,
• Establish link between AMO and AMOC variations in
  ocean reanalaysis
• Study potential predictability on long timescales
  (initial and boundary value problem), would this
  be useful?

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ENSO-monsoon interactions on paleo-timescales
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ENSO-monsoon interactions
JJA
Orbital forcing W/m2
Timm and Timmermann 2007, JCL
Abram et al 2007, Nature
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ENSO-monsoon-IOD interactions
Abram et al 2007, Nature
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Challenges

• How do meridional perturbations (meltwater
  pulses, orbital forcing) control ENSO and
  monsoon?
• Better interannual proxies for ENSO variability
• Understand the stability of teleconnections and
  the mechanisms modulating them

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The Indonesian Throughflowhow much is
wind-driven, howmuch thermohaline?
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Climate effect of Indonesian Throughflow
sea level difference cm between no-throughflow
and throughflow
SST difference K between no-throughflow and
throughflow
Schneider 1998
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Wind forcing of Indonesian Throughflow
Apply NCEP ERA40 winds to Godfreys Island Rule
Model
For the interior Ocean
Seasonal cycle of the ITF, in absolute value
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Wind forcing of Indonesian Throughflow new
dataset

• We have calculated both the stream function and
  the steric heights for NCEP and ERA40 wind
  products, with the Indonesian Throughflow Passage
  open in a quasi-realistic topographic setting.
  The data provides monthly, annual mean and
  seasonal outputs of both variables in NetCDF
  format. These data are now available from the
  Tasmania Partnership of Advanced Computing
  (http//digitallibrary.tpac.org.au)

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Modulation of South China Sea Throughflow

• South China Sea Throughflow measures the water
  mass exchange between the SCS and Pacific Ocean.
  (Qu, et al. 2005)
• Its interannual variability can be explained by
  the trade-wind remote forcing associated with
  ENSO. (Wang et al., 2006)

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AMOC effect on ITF reduction of 6Sv
Wind-stress induced by AMOC collapse
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Indonesian Throughflow as part of the global
ocean conv.
Speich, Blanke, and Cai, 2006
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ITF as transmitter of thermocline anomalies
Post-1980, SODA
Cai et al 2005, GRL
Pre-1980, SODA
Shi, Ribbe, Cai and Cowan, 2007
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Challenges

• Does the ITF precondition IOD gt Anna
• JEBAR vs. Godfrey
• How much of the wind itself originates from the
  AMOC?
• How much of the JEBAR effect is due to the
  conveyor belt circulation?
• What modulates ITF on paleo timescales?

Shi, Sue and Ribbe, Joachim and Cowan, Tim and
Cai, Wenju (2007). A dataset of the wind-driven
global ocean circulation for climate research.
Technical Report. Joachim Ribbe, Toowoomba,
Australia.
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International field program/ process studySPICE
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Southwest PacIfic Ocean Circulation and Climate
Experiment SPICE A. Ganachaud
JISAO/PMEL/NOAALEGOS / IRD Nouméa-Toulouse
Lines show geostrophic streamlines on the
isopycnal
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Southwest PacIfic Ocean Circulation and Climate
Experiment SPICE
SPCZ
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Seasonal variation of supergyre
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SPICE questions
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Modeling strategy regional zooms
High resolution global/regional ocean, atmosphere
and climate models
Blue Link (CSIRO/BOM) ROMS/Mercator (IRD Nouméa)
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A-Existing large scale programsB-Pilot
studiesC-Sustained observations
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SPICE

• A synergy has emerged to organize a coordinated
  experimentin the South West Pacific
• Goal Observe, Model, Understand, the role of SW
  Pac oceanLarge scale decadal climate
  modulation-ENSO, TasmanGeneration of local
  climate signatures
• The science plan is based on existing
  infrastructures
• SPICE is integrated in the broader CLIVAR context
• www.ird.nc/UR65/SPICE

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Chinese activities in the South China Sea
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South China Sea version of China GOOS (State
Oceanic Administration, China)
ChinaArgo
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South China Sea version of China GCOS (China
Meteorological Administration)
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SEATS Southeast Asian Time Series Study
SEATS since 1999
Acting a key site for JGOFS (finished), SLOAS
(ongoing), GEOTRACES (planning)
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SCSIO version of the SCS network
Ongoing repeated cruises the northern SCS and
southern SCS. Planned time series sites Xisha
Isl. Sta. Nansha Isl. Sta.
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2004-2006 Repeat cruises in the northern South
China Sea carried by the SCSIO, China Academy of
Sciences.
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Role of local air-sea feedback in the TCs
development in the South China Sea
The first TC in the NW Pacific in 2006 happened
in May, much earlier than normal and sudden
developing in the SCS due to warm SST
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What determines long term behavior of WWTP

• AAMP, IOP, Pacific panel share the same interest
  in MJO and WWBs and their modulation due to ENSO
• Joint interest in Northwestern tropical Pacific
  and its influence on the monsoons and NAO

Black West. Trop. Pacific gradient 12S - 4N
8N - 20N Red NAO index From Kurcharski and
Molteni 2005
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A gap in the era of post-TOGA the western
Pacific and its marginal seas
western Pacific marginal seas
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Monsoon circulation and its impact on weather and
climate over East Asia
Water vapor transport in climatological July
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Monsoon induced upwelling in the western SCS
Chla field in the western SCS Xie, JGR, 2003
Tang, JGR, 2004
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Cross-cutting issues

• ITF
• ENSO-monsoon interactions
• ENSO-IOD interactions
• ISO-ENSO interactions
• Warm pool dynamics
• ISO and SPCZ

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Activities

• Pacific panel could help to organize the
  monsoon-ENSO conference in 2007/08
• Propose analysis of AR4 simulations to study the
  physics of climate change in the warm pool and
  SCS
• Propose analysis of AR4 simulations focusing on
  SPCZ dynamics, South Pacific SST variability and
  impacts on Australian rainfall
• ENSO-monsoon summer adventure camp for students