Through funding sourced from the Swedish Secretariat for Environmental and Earth System Sciences, a workshop held was held in Johannesburg during May 2015 in which representatives from the four CORDEX-Africa regions gathered for three days to discuss the analysis framework for the next series of analysis workshops that will take place during 2015 and 2016. These planned workshops aim to build on the highly successful CORDEX-Africa activities during 2011-2013 that saw nine papers published and facilitated interactions between climate and impact scientists.



From left to right: Grigory Nikulin (SMHI, Sweden), Francois Engelbrecht (CSIR, South Africa), Chris Lennard (UCT, South Africa), Daniel Michelson (SMHI, Sweden), Genito Maure (Universidade Eduardo Mondlane, Mozambique), Vincent Ajayi (Akure Federal University of Technology, Nigeria), Sarah Osima (Tanzania Meteorological Agency), Eleanor O’Rourke (IPOC), Wilfried Pokam (University of Yaounde, Cameroon) and Daniel Nyanganyura (ICSU African Regional Office, South Africa).


During the meeting the objectives of the next series of workshops was outlined and the opportunity was taken to introduce the IPOC to the delegates. However, the main aim of the meeting was to develop research questions for each of the four regions that would form the analysis framework to be followed in the next series of workshops.

The regional questions are set out below and you are invited to comment on them or make suggestions by emailing Chris Lennard (lennard at csag dot uct dot ac dot za).


1. Non-region specific questions (meta questions)

  • How to link the four domains as they are really interacting – what is seen in East Africa may then be seen in Central and West Africa, Perhaps also include three overlapping domain so not just having standalone domains?
  • Quantification of the “added value” of the downscaled product with respect to the driving ERA-Interim and GCM data.


2. West Africa

West African driven by two major air masses – SW monsoon in summer and during winter under influence of north easterlies. Complex interaction of many other processes like AEJ, TEJ, AEW, meridional temperature gradient, gradient of moist static energy etc.

Three focus groups proposed:

(1a) Model evaluation (ERA Interim and GCM historical runs)

  • temperature
  • rainfall
  • onset & cessation of rainfall
  • spatial & temporal distribution of rainfall (monsoon) and temperature
  • diurnal cycle (specifically rainfall)
  • intra-seasonal, interannual and multi-decadal time series analysis
  • extremes

(1b) Dynamics of West Africa

  • Are the models able to simulate key dynamic features such as MCS, AEW, TEJ which account for rainfall distribution in W. Africa?
  • Determine representation of MSC
  • Look at feedback of land surface
  • Feedback of aerosols – relevance to Harmattan
  • Teleconnections – ENSO etc

(2) Scenarios & projections

  • Focus on changes in the above over the next 50 years but up to 100 years

(3) VIA connections

Working with communities running impacts models:

  • agriculture – crop/forest sustainability
  • health – disease outbreak (malaria, cerebral spinal meningitis) effect of climate change
  • water resources management – freshwater, HEP, irrigation

User engagement activity:

  • policy


3. Central Africa

Climate related to annual movement of ITCZ crossing twice a year with two rainy seasons according to position of ITCZ. North and south component of AEJ, also TEJ, low level westerlies bringing moisture from the Atlantic Ocean. Jets at between 650-700hPa, low level westerlies peak at 925hPa and the TEJ at 100-200hPa.

Groups will follow the same format as the West African group but also will include:

  • ITCZ – focus on vertical moist stability (surface to 850hPa).
  • Diabatic heating – strong influence of forest.
  • Interaction between forest and climate – impact on changing climate on forests (FPS??)
  • Should look at synoptic and mesoscale processes
  • CRCM and RCA3 had a good representation of the diurnal cycle
  • Some indicator or proxy of collective mesoscale effect in this area
  • Aerosols
  • Role of teleconnections

VIA community interaction

  • hydrological modelling


4. Southern Africa

A. Coastal storms and processes

For evaluation and change purposes the following systems are proposed for assessment

1.     Tropical cyclones

  • Trajectories
  • Landfall frequency and location
  • Rainfall intensity
  • Trends frequency
  • Over East Africa: TC to east/west of Madagascar is dry/wet because of messing with Congo boundary?

2. Tropical lows (storms)

  • Trajectories
  • Location
  • Rainfall intensity and intensity changes
  • Wind speeds and gust speeds

3. Cut off lows

  • Trajectories?
  • Location
  • Rainfall intensity and intensity changes
  • Can RCM develop COL at the boundary

4. Mid-latitude cyclones

  • Trajectories
  • Rainfall intensity and changes
  • Wind speeds and gust speeds
  • Tricky because of southern boundary?

5. Mesoscale convective systems (Inland systems)

  • Can the CORDEX resolution get to MCC/MCS?
  • Are there proxies to use
  • Hail, wind and lightning
  • Identify with wind shear, OLR, AEW, CAPE
  • MCC climatology?

6. Tropical Temperate Troughs (Inland systems)

  • Association with rainfall and extreme rainfall
  • Variables to assess in cloud – OLR in the models

B. Other variables

1. Wind

  • West coast for fog and fisheries, can resolution capture this
  • Biodiversity
  • Wind energy – can provide information on how wind potential can change in the future.

2. Solar

  • Solar power – cloudiness

3. Ocean currents (FPS? as regional ESM study)

  • Coupled regional models – upwelling along west coast and Agulhas/Mozambique currents under climate change (important for east coast rainfall)
  • Position of the southern and eastern boundary of CORDEX-Africa a concern

C. Interesting regions to study

Limpopo basin “dry slot”

  • why is this region so comparatively dry?
  • do RCMs capture this

Zambezi basin

Greater Ruaha basin

D. Running simulations (CSIR, CSAG & possibly Mozambique)

  • Running WRF-Hydro, CCAM CABLE,
  • Simulation idea: have CCAM and WRF as semi-earth systems regional models and run ERA-Interim period
  • Set of analysis questions will need to be developed.


5. East Africa

Governing position of the ITCZ and related dynamics

  • 4 high pressure systems (Mascarene, Azore, Arabian ridge and St Helena high)
  • wind systems
  • moisture transport
  • q850 or q700, Congo basin
  • Monsoon winds that affect MAM rainfall onset and cessation
  • Westerlies from the Congo associated with tropical cyclones?

Waves: Easterly and Westerly waves

Variables required for evaluation and change assessment

  • Winds 700, 200
  • OLR

East Africa wetting question

  • Most GCMs (and RCMs?) project wetter climate but historical trends do not show this
  • Is this a CC signal, natural variability, is it RCM or GCM specific,


  • ENSO, IOD, NAO, other…..


6. Other general themes

Droughts and mega-droughts

  • drivers of drought (synoptic, local and teleconnective)
  • ETCCDI and parametric indices
  • wind speed relationship with temperature
  • what type of drought are you interested in (meteorological, agri and hydrological)
  • Soil moisture content questions (impact of rainfall and rising temperature)

Temperature analyses

  • Heat waves
  • Power demand, disease zones, ecology and agriculture, water demand,

Temperature – rainfall – evapotranspiration nexus


  • Feedbacks in a warmer climate

Thermodynamic changes and rainfall parameterizations (Clasius-Clapeyron)


  • Different types of vegetation produce hydrophobic and hydroscopic particles which impacts cloud and rainfall
  • Look at models that have an aerosol climatology
  • Characteristics in the transition/pre- seasons are important for fire

Do RCMs capture recirculation patterns of aerosols?

  • Can RCMs reproduce these
  • Are they even in the reanalysis?