WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

IMPACT OF LAND USE CHANGE ON THE CLIMATOLOGY OF

WEST AFRICA

SARR, A. (SENEGAL) MONKAM, D. (CAMEROUN)

INTSIFUL, J.D (GHANA)

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

OUTLINE

• INTRODUCTION

• MODEL CONFIGURATION

• VALIDATION AGAINST RE-ANALYSIS

AND CRU DATA

• SENSITIVITY TESTS

• CONCLUSION AND OUTLOOK FOR

FUTURE RESEARCH

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

MOTIVATION

• PRESENT UNIQUE FEATURES OF REGION

DROUGHTDESERTIFICATIONDEFORESTATION

LANDUSE CHANGE

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

MAIN CLIMATOLOGICALFEATURES

• LOWER TROPOSPHERE (MONSOON)

• MIDDLE TROPOSPHERE (AEJ)

• UPPER TROSPOSPHERE (TEJ)

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

MODEL CONFIGURATION-1

• Physics : - Spatial resolution :

Horizontal - 50 kmVertical - 18 and 23 level

- Schemes : AS / FC GRELL / AS

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

MODEL CONFIGURATION-2

• Run length : 38 days 25/07/96 to 01/09/9625/07/95 to 01/09/95

• Initial & lateral boundary conditions : ECMWF Re-analysis(ERA)

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

VALIDATION AGAINST REANALISES & CRU DATA

• Surface temperature• Meridioanal flux at 925 hPa• Zonal wind filed at 700 hPa• Zonal wind field at 200 hPa

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

SENSITIVITY TESTS

• Landuse change:

Default CorrectedScenarios - 75% desert, 25% savanna

• CPS and Vertical Resolution

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

LANDUSE MAPS

Corrected Scenario

DefaultUSGS

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

MLY. MEAN TEMPERATURE

DEF

SCE

COR

ERA

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

MONTHLY MEAN AEJ

DEFSCE

ERA

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

MONTHLY MEAN TEJ

ERA

SCEDEF

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

DEF SCE

ERA

MONTHLY MEAN SPC. HUMIDITY

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

PRECIP

DEF-CONV

SCE-ACC

DEF-ACC

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

CONCLUSION AND OUTLOOK FOR FUTURE RESEARCH

• OBSERVED CLIMATIC CHANGES IN LAND USE SCENARIO• GENERAL FEATURES OF TEMP.,TEJ & AEJ WELL CAPTURED

WITH FEW DISCREPANCIES (LOCALLY)• GENERAL FEATURES OF HUMIDITY WELL CAPTURED BUT

BIAS OVER THE OCEAN AND INLAND• FEATURES OF TOTAL PRECIP. POORLY CAPTURED DUE TO

CONFIGURATION PROBLEMS AND PHYSICS • GENERAL FEATURES OF CONVECTIVE PRECIP. WELL

CAPTURED BUT SIGNAL TOO WEAK TO REFLECT IN TOTAL PRECIP.

• RESULTS ONLY PRELIMINARY & NEEDS MORE OPTIMISATION• OF THE MODEL PHYSICS

WORSHOP ON MODELING PWC/ICTP 26-96 June 2003

THANK YOU