CORDEX-Africa Impacts Atlas Prototype

Funding to establish a prototype of the CORDEX-Africa Impacts Atlas has been kindly provided by the Swedish Government through the Swedish Meteorological and Hydrological Institute. A small workshop was convened in August 2017 in Cape Town that brought together climate and agriculture modeling scientists to develop the goals and aims of the prototype atlas as well as discuss the atlas content.

The primary goal of the prototype atlas is to develop a platform that can present sensible/usable information about the regional climate over West Africa when the global mean temperature reach significant warming levels of warming 1.5, 2 and 4 degrees above pre-industrial period as well as the impact this may have on agriculture .

The aims of the project are as follows:

1. Determine the dates the significant warming levels (SWLs) are reached in 2 RCPs (2.6 and 8.5) use CMIP5 GCM data

2. Develop regional climate metrics based on temperature and rainfall from CORDEX downscalings

3. Generate a suitability index for a selection of crops in the West African region using a crop suitability model (EcoCrop) at the time these SWLs are reached.

4. Present the results of the above aims in a sensible and useful way on a web platform

The work will be partitioned into three work packages, one to develop the climate atlas, one to develop the Agriculture atlas and a WP on Visualization. Results will be presented as an online atlas that facilitates the download of climate and impact model data in formats including netCDF, shape files and ascii.

Below is a brief overview of output that can be expected from each work package:

1. The Climate atlas work package

Seasonal means

– mean/maximum/minimum temperature, precipitation (mm/day, mm/season)

Number of wet days (more then 1 mm/day per season and annually) and total amount of precipitation for them

Consecutive 5 and more dry days

Consecutive 5 and more wet days

Number of days above 10, 20, (30) mm/day

Maximum consecutive 5-day precipitation

Maximum length of dry spell, maximum number of consecutive days with RR < 1mm (per season and annually)

R95pTOT, Annual total PRCP when RR > 95p


Number of hot days (above 25?, 30, 35 and 38)

Number of consecutive (5-day) of hot (30 and 35) and dry days (< 1 mm/day)

Heat waves for example WSDI, Warm spell duration index

Need a well used/simple index for this

2. The Agriculture atlas work package

Agri-climate indices including

– Onset (using agri-centric Agrhymet definition )

– Extremes

– Combinations of extreme metrics

– Seasonal rainfall statistics over major and minor growing seasons

Crop Suitability Indices for a variety of crops grown in West Africa

3. The Online Atlas work package

Searchable atlas that provides information on projected changes in climate and agriculture

Downloadable images

Data downloadable as shape files, netcdf and ascii.

Documentation on best practice including what not do do with the information

If you have any thoughts or questions, please feel free to contact Chris Lennard at CSAG.