TITRE TITRE TITRE

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• The Tropical water cycle in the frame of Climate
  Change
• General scientific objectives of the mission
• Mission and instruments specifications
• Relation to other missions
• Status of the scientific preparation

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• Energy exchanges and the tropical system
• Atmospheric energy budget in the intertropical
  zone and at system scale (radiation, latent heat,
  )

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• Atmospheric water and the tropical system
• Atmospheric energy budget in the intertropical
  zone and at system scale (radiation, latent heat,
  )
• Water budget of the systems (including
  precipitation and water vapor transport)

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• Dynamics in the tropical system
• Atmospheric energy budget in the intertropical
  zone and at system scale (radiation, latent heat,
  )
• Water budget of the systems (including
  precipitation and water vapor transport)
• Conditions of appearance and development of
  these systems (Surface temperature, water vapor,
  winds,)

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• Dynamics and the Tropical System
• Atmospheric energy budget in the intertropical
  zone and at system scale (radiation, latent heat,
  )
• Water budget of the systems (including
  precipitation and water vapor transport)
• Conditions of appearance and development of
  these systems (Surface temperature, water vapor,
  winds,)
• Life cycle of Mesoscale Convective Complexes
  in the Tropics (over Oceans and Continents)

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Main objectives of the Mission Convection - Water
Vapor - Radiation interactions - effect of the
water vapor distribution on convection
- re-distribution of water vapor by
convective systems -
feedback of water vapor on climate

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Main objectives of the Mission Convection - Water
Vapor - Radiation interactions - effect of the
water vapor distribution on convection
- re-distribution of water vapor by
convective systems -
feedback of water vapor on climate
Cloud and rain systems
relations to the energy budget - effect of
convective and associated clouds on radiation
- life cycle of mesoscale cloud systems, in
relation to surface properties,
radiation and latent heat
- changes in budget
of ITCZ and subsidence areas
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• Additional objectives
• Operational aspects cyclone forecasting,
  monsoon systems forecasting,
• interest for Indian meteorologists
  - interest for French
  tropical islands
  - interest for African monsoon areas

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• Additional objectives
• Operational aspects cyclone forecasting,
  monsoon systems forecasting,
• interest for Indian meteorologists
  - interest for French
  tropical islands
  - interest for African monsoon areas
• Contribution to climate monitoring
• Radiative budget (complementary to CERES) -
  Precipitation (enhanced sampling in the tropics)
  - Water vapour (tropical sampling)

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Principles of the Mission Frequent sampling of
the intertropical zone measuring - Cloud
properties and precipitation - Water vapor
horizontal and vertical distribution - Outgoing
radiative fluxes Association with operational
satellites (geo and leo)
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• Main Mission features
• Coverage 23N to 23S, repetition time from 3 to
  6 times per day
• Tropical Orbit (20 inclination)
• Wide Swath (altitude gt 800 km)

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• Main Mission features
• Coverage 23N to 23S, repetition time from 3 to
  6 times per day
• Tropical Orbit (20 inclination)
• Wide Swath (altitude gt 800 km)
• Study of Mesoscale convective systems gt 100 km
• Surface resolution from 10 to 40 km, depending
  on the parameter.

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• Relevant parameters and instrumentation
• Column water vapor, cloud water and ice,
  precipitation, sea surface parameters
• Microwave Imager radiometer MADRAS

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• Relevant parameters and instrumentation
• Column water vapor, cloud water and ice,
  precipitation, sea surface parameters
• Microwave Imager radiometer MADRAS
• Relevant channels
  Column water vapor
  23 GHz
  Sea surface wind 18 GHz
  Precipitation, cloud water 18, 23,
  36.5, 89 GHz
  Active
  convective areas, cloud ice 89, 157 GHz
  
  Two polarisations required for all
  parameters, except column water vapor (23 GHz),
  then conical scan

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• Main Madras channel characteristics
• Precipitation and cloud properties are best
  obtained from combination of channels. Proper
  combination requires identical field of views.
  This is specified for channels 18, 23, 36.5 GHz.

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• Main Madras channel characteristics
• Resolution at 89 GHz 10 km (cross track)
  with adjacent pixels, in order to get complete
  images of the active convective parts of the
  systems.
• Resolution for lower frequencies will be lower
  (40 km) with oversampling in order to keep some
  information on smaller scales

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• Main Madras channel specifications
• 157 GHz channel is an experimental channel
  intended to provide new information on ice at
  cloud top, eventually helping for precipitation
  estimation over land, and for lower layers WV
  retrieval. It will provide the best space
  resolution.

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• Relevant parameters and instrumentation
• 3D distribution of water vapor
• Microwave Sounder SAPHIR
• Relevant channels several channels sampling
  the WV absorption line at 183.31 GHz
• No need of polarisation measurement, as much
  levels as possible
• Cross track scanning, 6 channels

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SAPHIR humidity sounder 6 channels centered at
183.31GHz No  window  channel, but a channel on
the far wings of the line
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• Relevant parameters and instrumentation
• Outgoing radiative fluxes at Top of Atmosphere
• Wide Band Solar Terrestrial Radiation
  Radiometer ScaRaB
• Main channels Total and shortwave (lt4µm)
• Resolution 40 km, radiometric accuracy
  similar to previous ScaRaB (Meteor and Resurs).
• Ancillary VIS and IR channels

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Complementarity to other Missions Monitoring of
the Earth Radiation Budget ScaraB/Megha-Tropique
s could partially fill a gap in RB measurements
from CERES (Wielicki) Global Precipitation
Mission Madras/Megha-Tropiques could be
associated to this multi-satellite mission to
increase its tropical sampling.
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New target for GPM
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Status of scientific preparation of
Megha-Tropiques in France Year 2005 marked the
new start of the scientific studies on
Megha-Tropiques. A French mission team was
constituted in 2004  Michel Desbois (P.I.)
Laurence Eymard (SAPHIR) Rémy Roca (mission)
Nicolas Viltard (MADRAS) Michel Viollier
(ScaRaB) Sophie Cloché (data bases) In January
2005, a first meeting of a preliminary French
 science team  took place in Paris, an a
preliminary work programme for year 2006 was
established in March-April. Elements of this
programme were discussed with Indian partners in
April 2005 in Bangalore. The present Ahmedabad
meeting is aimed to start really common projects
around mission Megha-Tropiques, when it is
possible. A wide range of subjects of cooperation
have already been suggested and will have to be
discussed 
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• Actions devoted to algorithm developments
• Satellite data bases for testing algorithms and
  processing procedures of the Megha-Tropiques
  instrumental package.
• Microwave rain algorithm developments
  adaptation and evaluation of TRMM-based
  algorithms specific effort on the ice phase.
• Combined geostationary - microwave algorithms.
• Radiative fluxes retrievals at different
  space-time scales.
• Humidity retrievals in the perspective of SAPHIR

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• Actions devoted to validation of satellite
  products
• Precipitation retrieval validation (raingauges
  and radars) sampling and scaling effects.
• Validation for other quantities (ice
  microphysics, others)
• Different methods for water vapour determination
  (IR and MW sounders, GPS, )
• General use of the AMMA campaigns and data bases
  for satellite validation studies
• - Promoting specific campaigns for water vapour,
  clouds and radiative budget

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• 3) Actions devoted to MT sampling effects
• Use of geostationary observations to simulate the
  MT sampling of convective systems and their life
  cycle. To be performed over Africa, India and
  Brazil.
• Development of a simulator for MT from analyses /
  satellite observations to analyze the impact of
  MT orbit on the various fields retrieved
  (radiative budget, water vapour )

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• 4) Actions devoted to MT data scientific
  exploitation
• Assimilation of microwave data including MT in
  forecast models.
• Impact of dry subsidence areas in the subtropics
  on the global climate .
• Upper tropospheric drying influences on monsoon
  cloud systems and hence on monsoon variability.
• Construction of cloud climatology over the Indian
  ocean area.
• Structure of mesoscale convective
  complexes/systems over Indian Monsoon Region.
• Monsoon systems in India and Africa
• Use of microwave emissivity in complement of
  VIS-IR data for land surface properties.
• Cloud resolving models for Indian region using
  Microwave and radar data.
• Etc

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This list of actions is not limitative, and many
subjects have to be better defined. We have to
establish a new work plan, defining the different
tasks and their planning, and to determine which
actions will be pursued in France, India, or in
French Indian cooperation. The increasing
interest in studying tropical climate, the large
domains covered, as well as the need of using
previous experience gained from other satellite
projects , will also require participation of
scientists from other countries