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Prof. KONARE Abdourahamane , Profesor , Atmospheric Physics Laboratory ,

CLIMATE CHANGE AND HYDRO-METEOROLOGICAL HAZARDS IN AFRICA. Prof. KONARE Abdourahamane , Profesor , Atmospheric Physics Laboratory , University Felix Houphouet Boigny of Abidjan Cote d’Ivoire African Science and Technology workshop; BIUST, Palapye , 25-27 November 2013. OUTLINE.

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Prof. KONARE Abdourahamane , Profesor , Atmospheric Physics Laboratory ,

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  1. CLIMATE CHANGE AND HYDRO-METEOROLOGICAL HAZARDS IN AFRICA Prof. KONARE Abdourahamane, Profesor, AtmosphericPhysicsLaboratory, UniversityFelixHouphouetBoigny of Abidjan Cote d’Ivoire AfricanScience and Technology workshop; BIUST, Palapye, 25-27 November 2013

  2. OUTLINE • EVIDENCE OF CLIMATE CHANGE IN WEST AFRICA • OBSERVATIONS • MODELING • SOME FEATURES OF HYDRO-MET HAZARDS ACCROSS AFRICA • DROUGHT • FLOOD • DUST • FIRE • CONCLUSION

  3. CLIMATE CHANGE DEFINITION Climate change is a long-term change in the statistical distribution of weather patterns over periods of time that range from decades to millions of years. It may be a change in the average weather conditions or a change in the distribution of weather events with respect to an average, for example, greater or fewer extreme weather events. Climate change may be limited to a specific region, or may occur across the whole Earth.

  4. OBSERVATIONS Changes in rate of flow in West African rivers (Club du Sahel et de l’Afrique de l’Ouest, 2008) Ten-year average cumulative rainfall for four stations in the Sahel and in the 1950s, 1980s and 1990s

  5. OBSERVATIONS Between 1912 and 2011, the mass of ice on the summit of the Kilimanjaro decreased by more than 85 per cent Lake Chaddecreased by more than 90 %

  6. Climate change in Côte d’IvoireImplications for Hydrometeorologicalhazard During the past 50 years, dryingtendency have been reinforcedespecially in the northeastern part of the country. Number of hamattandays has increased in the south Future prjectionindicatespersistence of Drying, as well as highesttemperatureincrease This has strong implications in agriculture and Pastoralism,

  7. PROJECTED CHANGES OF THE AFRICAN CLIMATE Africa’s climate is changing, and it will effect temperature and rainfall. It is predicted to warm during the next century. All seasons in all regions will have a median increase in temperature from 3-4° C, It is also predicted that the annual rainfall will decrease in Mediterranean Africa, North Sahara and southern Africa but on the other hand, there will be an increase in rainfall in East Africa.

  8. MOCCAD: Scénarii climatiques (Pluies et températures) pour la Côte d’Ivoire avec RegCM4, selon A1B • Impacts futurs différenciés régionalement même à l’intérieur d’un même pays • Tendance à l’assèchement généralisé Implications importantes pour les feux • Rechauffement généralisé • à court et moyen terme • (horizon 2050). • Rechauffement relatif très • accentué en Côte d’ivoire

  9. EASTERN REGION Mean Baseline and future mean surface temperature for the December-February season under A2 Special Report on Emissions Scenarios (SRES) (AbebeTedege, 2010).

  10. DROUGHT Drought is an extendedperiod of months or yearswhen a region notes a deficiency in its water supplywhether surface or underground water. Generally, thisoccurswhen a regionreceivesconsistentlybelowaverageprecipitation

  11. DROUGHT IN SAHEL Rainfallanomaly SahelFamin, 2011 • humans, overgrazing, deforestation, • large scaleclimaticfactorsinflencedrought • Global dimming • Modelspredictreduction of 25% by 2100

  12. DROUGHT IN EASTERN AFRICA Famine in easternAfrica Precipitationanomaly An unusuallystrong La Nina, have interruptedseasonalrains for twoconsecutiveseasons. In many areas, the precipitation rate during the main rainyseasonwaslessthan 30% of the average of 1995–2010

  13. FLOOD A flood is an overflow of water that submerges or "drowns" land. The European Union Floods Directive defines a flood as a covering by water of land not normally covered by water.

  14. FLOOD IN SOUTHERN AFRICA Floods in the region are mostly linked to tropical cyclones and la nina that provide rain largely above normal Mozambique and Botswana experiment more flood events with most damages

  15. FLOOD The 2009 West Africafloods are a consequence of exceptionallyheavyseasonalrainfall in large areas of West Africa. Severalrivers, broketheirbanks, causing destruction of houses, bridges, roads and crops. The floods are reported to have affected 940,000 people across 12 countries, and caused the deaths of at least 193 people . In Ouagadougon, rainfall in one daywasequal to 25% of normal annualrainfall for the whole country.

  16. DUST UST • A dust storm or sand storm is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a strong wind blows loose sand and dirt from a dry surface. • Dust has several environmental and sanitary impacts.

  17. DUST EVOLUTION IN THE SAHEL 1970-1974 1957-1961 1983-1987 Icreased of dust concentrations over Sahel as response to the Decrease of precipitation over Sahel

  18. Temporal evolution of dust plumes Figure 5 : Evolution of dust particles (episode of March 17-21th simulated with the RegCM 4.0) from the African continent towards the Atlantic Ocean between March 19-24th 2010. Chad and Niger sources were active simultaneously during the first 3days (19th, 20th and 21st of March). spatial evolution was more accentuate than the temporal evolution. Dust plumes spent 3-5 days to pass through the continent to the Atlantic Ocean

  19. Zonal and meridian transport of dust JJA DJF MAM Dust sources location: 18o to 22o N The dust source around 18°N (Bodélé) quasi-continuous activity. Ascending altitude from DJF to JJA. Figure 6: Meridian profile of mean desert dust concentrations in troposphere μg/kg average between 66°W and 23°E for DJF, MAM and JJA. Trajectories linked to altitudes reached by dust plumes. DJF JJA MAM Dust transport strongly influenced by regional atmospheric dynamic. Figure 7: Zonal profile of mean desert dust concentrations in μg/kg in troposphere average between 0°N and 25°N for DJF, MAM and JJA .

  20. DUST INDUCED ATMOSPHERIC THERMAL VERTICAL PROFILE

  21. DUST IMPACTS ON PRECIPITATIONS Decreaseprecipitation over sahel and increase over the ocean

  22. URBAN AEROSOLS Health? Climate? Liousse and al, 2013

  23. FIRE

  24. NASA DMSP Operational Linescan System

  25. BB emission from AMMA Vs GfedV2 Some important differences especially in Africa on the estimates.

  26. EMISSION Central Africa ( South Sudan-DRCongo) major biomass burning source in the world High AOD values , especially west to the source: transport westwards of the BB plume

  27. DEPOSITION Wet deposition mainly over Congo Basin and Cameroon forest ( relation with zoetele high value (IDAF)) Dry deposition of BC in western africa source is as important as in central africa source

  28. CLIMATICS IMPACTS General cooling of BC and OC aerosol over the source areas ( Congo Basin) General decrease of precipitation as result

  29. CONCLUSION • Hydrometeorologicalhazards are burning issues withhighregionalcharacteristicscontrolled by climate change. • Their spatial and temporal variabilityremain a challenge for the scientificcommunity • Need to improveourpredictabilitycapability • Overcometechnicalconstraints • Theirregional nature recommend a regionalapproach

  30. THANK YOU FOR YOUR ATTENTION

  31. Observations Field campaign Computingfacility

  32. REGIONAL CLIMATE MODELLING Définitions Temps présent (validation en Côte d’Ivoire) Temps futur (projection)

  33. Downscaling Methods . • Two approaches exist for downscaling methods: • The dynamical approach is to explicitly solve the physics and dynamics of regional climate system; • The statistical approach based on finding a statistical relationship between local models and predictor variables. • These two approaches can be used independently or combined (statistical-dynamical methods). • The dynamic approach is often time-consuming calculation. • The statistical approach to it needs to find a method adapted to the impact that we want to study (parameters, area, ...) and to have historical data over a sufficiently long period (10-20 years) category.

  34. From Global to regional

  35. Changement d’échelle:Désagrégation dynamique et statistique

  36. VALIDATION MODELS-OBSERVATIONSpresent time (1990-2005) The models capture the annual cycle More efficient at Bondoukou Significant differences between models Sources of error Underestimation of the absorption of solar radiation Diurnal cycle of convection -Representation of subgrid processes EnsemblesApproach

  37. Comparaison RegCM-Ensemble- Obs Ensemble:Approach Combination of these models to generate an average model of the climate Reducing uncertainties The Ensemble performs better than model RegCM

  38. MERCI DE VOTRE ATTENTION

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