1 / 21

Simulation of present-day climate of tropical Africa Using the Hadley Centre regional climate modeling system

Simulation of present-day climate of tropical Africa Using the Hadley Centre regional climate modeling system . AIACC AF 20 Project Andre F. KAMGA , Gregory. S. Jenkins , Amadou T. Gaye , Adamou Garba , A. Sarr, and A. Adedoyin.

alethea
Download Presentation

Simulation of present-day climate of tropical Africa Using the Hadley Centre regional climate modeling system

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Simulation of present-day climate of tropical Africa Using the Hadley Centre regional climate modeling system AIACC AF 20 Project Andre F. KAMGA , Gregory. S. Jenkins , Amadou T. Gaye , Adamou Garba , A. Sarr, and A. Adedoyin

  2. African tropics experiences a highly variable climate and presents a significant vulnerability to probable climate change.

  3. Acquiring knowledge of possible future climate change for the next decades will facilitate design and implementation of adaptation strategies.

  4. Numerical simulations with Global Circulation Models (GCMs) are appropriate tools to address global to sub-continental scale climate change and impacts ( Giorgi et al. 2002) • To address country, sub-country and local scale climate change consequences or impacts, high resolution climate Scenarios are required. Regional Climate Models (RCM) are tools to develop high resolution climate scenarios. • We examine hereunder a RCM simulation of some aspects of present-day (61-90) climate of tropical Africa.

  5. Why do we examine models simulations? • To guide future improvements of climate models • To facilitate interpretation and use of models climate forecasts or climate change scenarios.

  6. Precis is a regional climate modeling system developed by UK Metoffice Hadley Centre for climate prediction and research.The Hadley center regional climate modeling system have been used to conduct experiments over Europe, India and Southern Africa. The Boundary Conditions Are Provided by a 30 Year ( 1961-1990) Integration of HADAM3H Which Is an Atmospheric Higher Resolution (150 Km) Version of HADCM3.

  7. PRECIS TEMPERATURE SIMULATIONS AND NCEP/CDAS REANALYSIS.

  8. Temperature Climatology • Temperatures above 30°C at sub-country scale are simulated with positive Biases up to 2°C. • Regional monthly variability of temperature is well captured by Precis. • Locations with high temperatures ( > 30°C) are well simulated by PRECIS RCM. • Therefore, there may be some skill in capturing areas at a sub-country scale that may experience temperatures above a given threshold in future climate scenarios with Precis.

  9. PRECIS PRECIP SIMULATIONS AND CRU ANALYSIS.

  10. Precipitation is overestimated over the ITCZ . • Regional annual cycle of precipitation is well captured. • Heavy precipitation locations in the ITCZ core are simulated. • Therefore, there may be some skill in capturing areas that may experience heavy precipitation or flooding with overestimation of precipitation intensity.

  11. Discussions • There is generally a surface temperature warm bias (1-2°C) over much of land areas. A systematic strengthening of St Helena High as well as the low-level monsoon winds (warm air masses) are common behavior of many GCMs. Therefore, the warm bias in the RCM is probably related to circulation bias of the driving GCM.

  12. Moreover, a tropospheric cold bias in the tropics has been noted in the driving GCM leading to a reduction of static stability, promotion of convective ascent, and intensification of the hydrological cycle. • The observed overestimation of precipitation in the RCM over ITCZ is probably related to biases in the circulation and temperature profiles of the driving GCM.

  13. CONCLUSION« The annual cycle of precipitation and temperature are well simulated by the RCM from sub-continental to sub-country scales. Sub-continental to sub-country scale areas that have experienced heavy precipitation and high temperatures are reasonably well captured. »RCM runs with Reanalysis as driving data may shed some lights on the extent to which the main source of RCM biases are the driving GCM data.

  14. To improve our capacity to interpret and use models, extensive validation experiments are needed and relationships between scenarios verification and scenarios value could be investigated. “ If forecasts or a climate change scenarios do not contain the information one needs, or are not presented in a manner such that one can extract that information then one simply stops buying them and speaks badly of them in cities wine bars or sue the forecasts vendors.”

More Related