Challenges in monsoon system study

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Challenges in monsoon system study

• The monsoon systems are manifested as
  land-atmosphere-ocean coupled systems, exhibiting
  a variety of time and space scales that are
  governed by complex physical processes and their
  interactions.
• Due to our lack of understanding these processes
  and interactions, large uncertainties still exist
  in prediction of the monsoons on local, regional,
  and continental-scales.
• Monsoon predictions require better models, and
  better models require improved physical
  parameterizations, which in turn require more
  comprehensive observations. 
• Since the monsoon systems possess a large range
  of variability from diurnal to decadal time
  scales, prediction is a challenging test for the
  modelling community. 
• Given the importance of the monsoons in driving
  the energy and water cycle, improving model
  physics in monsoon regions will result in better
  models for other applications such as global
  change, and water resource assessments.

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This workshop was a unique and timely
opportunity to promote a new initiative of the
pan-WCRP monsoon system prediction studies,which
should be an essential part of the new WCRP
strategy.
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WS recommendations (selected) 1

• Targeted workshops are envisioned as an important
  mode of interaction for sustaining CLIVAR and
  GEWEX interactions. These can be held in
  conjunction with existing panel meetings, as
  sessions at conferences, or independently.
• The near-term (1-2 years) goal is to improve the
  simulation of the diurnal cycle of precipitation
  and convection in global models by making use of
  regional climate models and cloud-resolving
  models that have more comprehensive physics. This
  is seen as the primary near-term goal that will
  crosscut the expertise of CLIVAR and GEWEX.

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• Improved modeling of the intraseasonal
  oscillation, with large-scale convection in the
  tropics on a time scale of 30-70 days. This
  phenomenon straddles numerical weather prediction
  and climate, and is a potential source of
  predictability that has not been realized due to
  its poor representation in models.
• Need for more process studies and modeling of the
  Maritime continent and the Indian Ocean.
• Better understanding of the atmospheric moisture
  distribution and transport.
• Sensitivity testing to determine the resolution
  necessary in global models to simulate
  multi-scale interactions that dominate the
  Earths monsoon systems.

WS recommendations (selected) 2
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WS recommendations (selected) 3

• The decay of the present observing system needs
  to be reversed.?role of GEOSS is important!
• Improved (and sustained) observations are needed
  over sparsely sampled regions of the tropical
  oceans, especially the Indian Ocean.
• Better observations of land surface conditions
  are needed (e.g., soil moisture, snow cover, snow
  depth) for understanding processes, and because
  these quantities can serve as boundary conditions
  for model simulations.
• The role of aerosol and dust and its impact on
  the development of monsoon precipitation should
  be investigated, though at present these may be
  secondary to errors in the basic structure of
  monsoon simulations.

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Diurnal cycle of rainfall by TRMM-PR
The most humid area in the tropics show large DC
in time-space.
(Ichikawa and Yasunari, 2006 J. Climate)
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OLR and wind (850hPa)
MJO disturbance developed between Jan to Feb in
2001
Jan21-31
Feb1-10
ISO propagated through the islands, with apparent
Kelvin-Rossby response.
Feb11-20
Feb21-28
Ichikawa and Yasunari, 2007 submitted to GRL.
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????????????????? TRMM3B42
(???0.1?0.2?0.4?0.6?0.8?1mm/h) ??30-60?????????
OLR(???-5?-20W/m2) ??700hPa???????(????????????
!!)
Comparison with westward propagating case (June
2001)
Feb. 2001
Jun.2002
??? ????
??? ????
??
??
m/s
m/s
??
??
??
??
m
m
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Fine structure of MJO
shadedOLR(-190-240- W/m2) whitezonal wind
at 600hPa(solid2,dash10m/s) colordiurnal
cycle filtered rainfall 0.2, 0.4 mm/h
Time-longitude section of rainfall between Eq-5S
Propagating rainfall activity associated with the
diurnal cycle over and around the island
?? Propagating diurnal disturbance (PDD)
15-20m/s
(Ichikawa and Yasunari, 2007 submitted to GRL.)
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Abnormally heavy flood occurredin southeast Asia
during winter monsoon surge in 2006/2007
This extreme event occurred in abnormally warm
winter monsoon in east Asia (under the global
warming trend?!).
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Rainfall amount and mean low-level(925hPa)
circulations during heavy rainfall events of
17Dec.-20Dec.2006
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Time-sequence of V 925hpa Strong NE monsoon
surge was likely to cause heavy rainfall
events.
15DEC
16DEC
17DEC
18DEC
19DEC
20DEC
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Heavy rainfall was modulated by diurnal cycle of
meso-scale convective system.
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MJO
Flood over Malay peninsula ? stagnant rainfall
Heavy rainfall over Jawa
2N-6N Average
Flood over Malay peninsula ? gradual eastward
propagation
Heavy rainfall events were also associated with
MJO from IO.
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Meso-scale disturbances originated from DC
convective sytem over Tibetan Plateau(Yasunari
and Miwa, JMSJ, 2006)
Tibet P.
Tibet P.
Eastern Edge of Plateau
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Diurnally-developed convergence line in some
cases expand toward the eastern edge of the
Plateau, to form meso-asystems over Meiyu Frontal
Zone (Plateau Edge CyclogenesisPEC)
(Yasunari and Miwa, JMSJ, 2006)
High-resolution GAME RA data used
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Scientific rationales for AMY (IMY) and YOTC

• Multi-scale interactions from meso-scale to
  planetary-scale are essential for dynamics and
  prediction of ISV and seasonal march of monsoons,
  which include time scales from DC to ISV and SC.
• Global-scale simultaneous satellite observations
  with high-resolution (with space time) are
  essential for resolving these interactions,
  through 30m. to 1hr obs. of the geostationary
  met. satellites.
• Coordination of in-situ regional observations and
  modelings relevant to various international/nation
  al projects should be optimized in conjunction
  with the intensive satellite observations.
• High-resolution reanalyses based on the data of
  these IOPs (for boreal summer and winter monsoon)
  will provide invaluable data for improving daily
  to seasonal predictions.

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In this workshop, we need to discuss

• How to coordinate various regional experiments
  during IOP 08-09
• Optimized operation of satellite observations
• Data exchange and management policy
• Cooperation in modeling acitivity including
  capacity buildings in monsoon countries
• Common products for monsoon study and prediction,
  e.g., high-resolution data assimilation

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Objectives of the Workshop

• This Pan-WCRP workshop on the monsoon climate
  systems aims to integrate our current
  understanding of fundamental physical processes
  that govern the various monsoon climate systems,
  and to promote better predictions using a
  hierarchy of models.
• This workshop should also be a unique and timely
  opportunity to promote a new initiative of the
  pan-WCRP monsoon system prediction studies, which
  should be an essential part of the forthcoming
  COPES (Coordinated Observation and Prediction of
  the Earth System) as a new WCRP strategy.
• Organizing committee
• T. Yasunari (Co-chair), K. R. Sperber
  (Co-chair), W. Higgins, K.M. Lau, J. McCreary,
  C.R.Mechoso, J. Polcher, K. Puri, J.
  Slingo, C. Thorncroft, B. Wang, G.-X., Wu

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The follow-up workshop on diurnal cycle of
rainfall over land ocean

• was held as part of the Sysmatic Error Workshop
  of WGNE in San Francisco, February 12-16 2007.
• 1st. International workshop on AMY will be held
  in Beijing, April 23-25, 2007.
• 2nd Pan-WCRP monsoon workshop to be expected in
  conjunction with the 1st Science workshop on the
  new CEOP, in Bali, Indonesia, September 2007.