PhD Project

Development of a scale-independent cloud process parametrization for global climate models.

(Extramural Research Program, DWD)

• Evaluation of cloud process parametrizations (e.g. development of theoretical testcases)
• Evaluation of statistical moments of total water mixing ratio (high resolution model)
• Development of an (improved) statistical cloud cover parametrization (probability density function, prognostic equations for variance and/or skewness)

Advisors: Verena Grützun, Bjorn Stevens and Johannes Quaas

Motivation: Clouds play a major role in weather and climate. Precipitation originates from them, and they strongly alter the planet’s albedo depending on their microphysical characteristics. In numerical modeling of weather and climate it is therefore crucial to appropriately represent clouds in the atmospheric system. Different parametrizations and the lack of understanding of clouds are known to be one of the main reasons for uncertainties in up to date global climate simulations. In current climate models the sugrid-scale variability of total water is only crudely taken into account. A more detailed consideration of this subgrid-scale variability (e.g. by application of a more realistic probability density
function) might improve the representation of clouds.

Research Interests

• Cloud parameterizations in global climate models
• Mathematical description of processes in the atmosphere (clouds)
• Numerics (e.g. modelreduction, solution of large linear systems)
• Mathematical modelling of the Earth System

Summerschools

• 4th Earth System Modelling School (EaSyMS10) in Hamburg (August/September 2010)
• European Research Course on Atmospheres (ERCA 2011) in Grenoble (January/February 2011)