AMMA. A frican M onsoon M ultidisciplinary A nalyses A nalyses M ultidisciplinaires de la M ousson A fricaine A frikanischer M onsun: M ultidisziplinäre A nalysen A nalisis M ultidiciplinar de los M onzones A fricanos A frikanske M onsun : M ultidisiplinære A nalyser.
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GCMs tend to have
an early rainfall onset
+ higher precipitation
than really observed
• Still numerous fundamental issues:
A major difficulty:Interactions of numerous processes that develop over a wide range of scales
West African Monsoon and the global climate
The water cycle
Surface atmosphere feedbacks
Scaling issues in the West African Monsoon
Convection and atmospheric processes
Physical and biological processes over land-surfaces
Aerosol and chemical processes in the atmosphere
Process studies are only the first step towards a better understanding and prediction of the African monsoon
(CNES, CNRS/INSU, IRD, Meteo-France)
Need of specific & coordinated efforts over Africa
Help to re-enforce collaborations between countries & disciplinaries
- AMMA Scientific Steering Committees exist in Africa (AMMANET), UK, US and France
- First draft of International Science Plan is nearly finished
- « Commitments » exist from funding agencies (USA, UK, France, Germany)
- Projects endorsed by CLIVAR & GEWEX
- the AMMA International Scientific Steering Committee is formed (1st meeting July 26th).
Analyses Multidisciplinaires de la Mousson Africaine
Analisi Multidisciplinare per il Monsone Africano
The European AMMA Integrated Project
The EU contribution to AMMA will enhance and federate national initiatives :
Partner institutions : human resources
France : INSU, IRD, CNES, Météo-France and MAE are contributing to a national AMMA program.
U.K. : NERC proposal
Germany : IMPETUS and GLOWA-Volta projects
Italy : Proposal to national agencies
Denmark : INTEO project
A total of 578 person.years will be dedicated to the AMMA-IP over the next 5 years. 133 person.years will be funded by the EU.The resources of the consortium
December 2003 : Solicitation for a full proposal.
February 2004 : full proposal submitted.
June 2004 : Definition of the first 18 month plan and negotiation with the EU.
October 2004 : Signature of the consortium agreement by all partners.
December 2004 : signature of the contract with the EU.
January 2005 : start of the project and the enhanced observing period.
2006 : Special observing periods.
2010 : end of the AMMA-IP project.The AMMA IP calendar
Long Term Observation Period (LOP)
Inter-annual and decadal variability
Enhanced Observation Period (EOP)
Two whole seasons (2005-2006-2007)
Special Observation Periods (SOP)
Rainy season of 2006 (IOPs of 2 to 4 days)
SOP 1 Pre-monsoon & Onset stages (~ 10 May- 5 July)
SOP 2 Monsoon maximum (~ 15 July - 15 Aug)
SOP 3 Late Monsoon (~ 15 Aug. - 15 Sept)
=> Northward penetration of moist air from the Gulf of Guinea up to
the Sahelian domain that strongly conditions the WAM (onset and intensity)
+ High sea surface temperature (<=> fluxes) variability !
(cold tongue,equatorial and coastal upwellings, )
Exchanges at the ocean-atmosphere interface :
- Restitution of flux fields over the GG
- Analysis from numerical OGCM
- Experiments from high resolution models
- Analyzis of the influence of surface heterogeneities
Circulation and oceanic processes in the GG (+ off Senegal+Guinea Dome):
- Coastal and equatorial upwellings studies + Cold tongue
- Mixing processes and water masses conversion studies
- Currents and hydrological measurements + analysis
- Zonal currents dynamic and their termination in the GG
- Tropical Instability Waves Studies (Jason projects).
- Coastal upwelling off Canaries (with ROMS numerical model)
- Dispersion/diffusion experiment in the GG (numerical and profilers)
Hydrology of the upper layers in the GG :
- Comparative studies of SST products
- Salinity in the GG studies (barrier layer effet? Influence on dynamic and SST?).
- Mixed Layer depth and heat content studies
- Models results analysis and validation, diagnostic studies
LOP & EOP
Cruises EOP (boreal spring and fall 2005 & 2007)
Cruises 2005 almost programmed
(Priority 1, with R/V SUROIT )
Perhaps: 12 Marvor drifters at 800m (resp. M.Ollitrault, LPO)
Cruise SOP-1 (boreal spring 2006)
(Priority 1, with R/V L’ATALANTE)
=> ? Deep layers with tracers ?
- Instrumented mast (or similar) for HF measurements (50Hz) of turbulence,
Thermodynamical parameters and radiation (0.1Hz).
API SOP (2)
Cruise SOP-3 (End August-September 2006)
- Dakar-> Cap Vert,
- Guinea Dome,
=> Air-Sea Interactions over warm waters in relationship with / during “cyclogenesis”
- Atmospheric Mesurements at the interface
- Drifting buoys “Marisonde”(surface & subsurface) & maybe “Aeroclippers” from Cap Vert
=> During both SOP cruises:
- Need of PIRATA buoys in the GG and farther west and north
- Close connections with TACE project studies
- Links and coordination with TACE & US-AMMA cruises (Ron brown)
- Links and coordination with IFM-Kiel in the framework of the EU IP.
+ attempts to get second R/V available, Antéa in the GG during SOP 1 off Bénin,
Senegalese R/V during SOP 3 off Dakar
Pirata FR11b -Feb.2003
Pirata FR12 -Jan-Feb.2004
Next one: Marion-Dufresne -July 2004
- ARGO profilers
- ADCP + Tsgraph
- Real time transmission of XBT and CTD profiles
(& ADCP from the Beautemps-Beaupré)
station in October 2003
(same parameters than
eastward extension of
Meteorological Station at São Tomé
Failed in December 2003!
(rare electronic component failure…)
Next intervention ASAP!!!
However, HF (10mn) measurements from
October, 17, 11h30 to December, 11, 24h.
24h measurements (Nov. 5, 2003)
Meteorological Station at São Tomé
Wind fields comparison:
Quickscat (black)-SãoTomé (red)
Pirata 0-0 (blue); Quickscat (black); ECMWF (green)
Very first and raw conclusions:
- Be careful to the used product…
- Quickscat known to overestimate for weak wind speed values but about OK in open sea (pirata sites)
- ? Effect of sensors height not corrected + orography effect on diffusiometry (Quickscat)
and probably on São Tomé measurements to evaluate!
For air-sea exchanges and flux estimates (=> & coupled models),
urgent need of precise winds (& humidity) in situ measurements