Mathematical Modelling of Atmospheric Convection for better Regional Climate Change Prediction

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The simulation of clouds and precipitation is one of the weakest aspects of weather and climate models and is known to contribute to errors in predicting the regional impacts of climate change. Clouds and precipitation are controlled by atmospheric convection which usually occurs on spatial scales smaller than the grid scale and consequently must be represented by a parameterisation. Questionable assumptions are made in convection parameterisations such as neglecting mass transport by convection.A new theoretical approach to convection parameterisation uses conditional averaging to calculate two values of momentum, temperature and density per atmospheric grid box: one for the convectively stable part of the flow and one for the convectively active part. This approach will enable transport of mass by convection. However, numerical solution of the resulting equations could have severe time-step restrictions. This project will involve designing a numerical technique for solving the conditionally averaged equations for representing convection that will not require a very small time-step. Support will be provided for the student to implement their numerical method in OpenFOAM, a C++ toolbox for solving differential equations.This project is part of the ``Revolutionizing Convective Parameterization'' project at Reading which is part of the NERC/Met Office programme ``Understanding and Representing Atmospheric Convection across Scales''. The student will therefore be part of a national network. This is an opportunity to contribute to model development that will directly feed in to weather and climate forecasting.