Gcm simulations for west africa validation against observations and projections for future change
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G.Jenkins, A.Gaye, A. Kamga, A. Adedoyin, A. Garba, A. Sarr AF20 - PowerPoint PPT Presentation


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GCM simulations for West Africa: Validation against observations and projections for future change. G.Jenkins, A.Gaye, A. Kamga, A. Adedoyin, A. Garba, A. Sarr AF20. NCAR Climate System Model. Version 1.3 (Gent and Boville, 1998) Atmosphere 2.8   2.8  , 18 vertical levels

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Gcm simulations for west africa validation against observations and projections for future change

GCM simulations for West Africa: Validation against observations and projections for future change

G.Jenkins, A.Gaye, A. Kamga, A. Adedoyin, A. Garba, A. Sarr

AF20


Ncar climate system model
NCAR Climate System Model observations and projections for future change

  • Version 1.3 (Gent and Boville, 1998)

  • Atmosphere 2.8 2.8, 18 vertical levels

  • Ocean component - variable resolutions 2.3 at the poles, 1.2 at the Equator, 45 vertical levels

  • Dynamic/thermodynamic Sea ice component

  • Land surface model (LSM)

  • Forced by greenhouse gases using starting times of 1870. Integrated out to 2100 using A1, A2 and B2 scenarios.

  • CSM has a relatively low climate sensitivity.


Current status
Current Status observations and projections for future change

  • 2003- Analysed NCAR Climate System Model (CSM) version 1.3 A1 scenario for West Africa.

  • 2004- NCAR CSM simulations of West Africa : Present-day and 21st Century Anthropogenic Climate change, Kamga et al. under review, JGR-Atmospheres

  • 2004- Drive the regional climate model with CSM data

  • 2004- Will write up RegCM/CSM for publication


Climate change climate variability linkage in west africa
Climate Change- Climate Variability linkage in West Africa observations and projections for future change

  • Observed

    • Reduced Rain rates associated with:

    • A southward shift in AEJ (700 hPa)

    • A weaker TEJ (200 hpa)

    • Warmer surface temps.

  • Can we use observed changes as a fingerprint for future climate and rain rates?


Reduction in the area of lake chad
Reduction in the Area of Lake Chad observations and projections for future change

25000 km2

To 1350 km2

from reduced rain

and irrigation


21st century regional climate change temperature
21st Century Regional Climate Change (Temperature) observations and projections for future change


Understanding future climate change in west africa
Understanding Future Climate Change in West Africa observations and projections for future change


21st century regional climate change precipitation
21st Century Regional Climate Change (Precipitation) observations and projections for future change


Ensemble model approach to climate change in west africa
Ensemble Model Approach to Climate Change in West Africa observations and projections for future change


Single model approach to climate change in west africa
Single Model Approach to Climate Change in West Africa observations and projections for future change


Single model approach to climate change in west africa1
Single Model Approach to Climate Change in West Africa observations and projections for future change


21st century temp prec diff
21st century temp./prec. diff observations and projections for future change


Temperature observations and ccsm
Temperature (Observations and CCSM) observations and projections for future change


Precip observations and csm
Precip. (Observations and CSM) observations and projections for future change


Csm and observed annual precipitation comparison
CSM and Observed annual Precipitation. comparison observations and projections for future change


Csm and observed annual temperature comparison
CSM and Observed annual Temperature comparison observations and projections for future change


Observed and simulated sahelian precipitation anomalies 20th century
Observed and simulated Sahelian Precipitation anomalies observations and projections for future change(20th century)


Observed and simulated sahelian temperature anomalies 20th century
Observed and simulated Sahelian Temperature anomalies observations and projections for future change(20th century)


Sahelian 21st temp trends
Sahelian 21st temp. trends observations and projections for future change


Sahelian 21st century temp anomalies
Sahelian 21st century Temp. anomalies observations and projections for future change


Sahelian 21st century precipitation trends
Sahelian 21st century precipitation trends observations and projections for future change


Sahelian 21st century precipitation anomalies
Sahelian 21st century Precipitation anomalies observations and projections for future change


20th and 21st annual temp comparison
20th and 21st annual Temp. comparison observations and projections for future change


20th and 21st annual precip comparison
20th and 21st annual Precip. comparison observations and projections for future change


Conclusion
Conclusion observations and projections for future change

  • CSM suggest that the region will become:

  • Warmer by 1.5-2.5C based on SRES scenarios.

  • Wetter --especially in the Sahel - due to an increase in low-level moisture (strengthening of monsoon flow).

  • Only small changes noted for Easterly waves.

  • CSM has significant biases in SLP, Surface air temperatures, precipitation and 200 hpa Zonal winds.


Future activities
Future Activities observations and projections for future change

  • Downscaling -- running a regional climate model (RegCM) for present-day and future climates.

  • Identifying biases in both GCM and regional climate model simulations.

  • Publishing results.

  • Work to reduce biases in GCM/RegCM.

  • Will use CSM 2.0 and CSM 3.0 data in the future.

  • Build human scientific capacity for decades of future research!!


Future directions
Future Directions observations and projections for future change

  • Analyze CCSM 2.0/3.0- Biases in Sea level Pressure, upper level winds much smaller.

  • Use A1, A2, B2 simulations from new CCSM runs to drive regional climate model.


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