SWAMMA brought together a recently-developed model that can for the first time capture these couplings with recently-acquired data from this highly data-sparse region (collected during the NERC-funded AMMA and Fennec projects). SWAMMA therefore combined for the first time a model that should be able to represent the key features of the summertime energy budget of the monsoon system with the first data sufficient to evaluate such a model.

SWAMMA evaluated the new model, quantifying the winds that generate dust uplift in the Sahara and Sahel. The project used the new data to analyse the impacts of variations in the sizes of dust particles. SWAMMA also evaluated the energy budgets of the monsoon system using both models and observations from AMMA and Fennec. SWAMMA quantified how the coupled processes of the monsoon system respond to the seasonal evolution of the monsoon's boundary conditions to control the seasonal stability of the monsoon rainfall and its variability. By bringing together the recently-acquired data and the new model with existing weather and climate models the project evaluated how process errors in operational models lead to systematic errors in predictions, both over West Africa and globally. The project provided metrics for the processes that must be captured by operational models for them to capture the key processes and couplings in the West African monsoon system.

Objectives: The overall objective of SWAMMA was to quantify the balances of West African Monsoon (WAM) processes (dynamic, convective and radiative) that determine the stable states of the monsoon system, their stabilities and transitions, and how the monsoon system responds to perturbations.

Specific objectives within this were to understand and quantify:
(1) How moist convection affects dust and dust uplift
(2) The balance of WAM processes (dynamic, convective and radiative) that determine the energy budget and state of the WAM system and its synoptic variability
(3) The time-evolution in the balance that determines the state of the monsoon through its seasonal cycle.
(4) The impact of an improved representation of the WAM on the state of the global atmosphere.
In each case we will assess how these processes are represented in models with a range of complexities and resolutions, and therefore we will assess the implications for weather and climate prediction. This will allow:
(5) The determination of metrics of the key processes that models must capture to represent the processes controlling the variability in the WAM system.
These objectives required a preliminary objective:
(0) to produce new convection-permitting simulations of the WAM system with a prognostic representation of dust, with the representation of dust informed by recent observations from field campaigns.