Do models capture clouds?

by Umar Saeed, Sophia Schäfer, Ioannis Binietoglou, Paloma Borque, Lia Amaral

The topic of the “number crunchers” group was to understand the use of Large Eddy Simulation (LES) models to study cloud formation. LES are very high resolution models, suitable to study convective processes and cloud formation in scales not covered by typical weather models. For our group project we used the Dutch Atmospheric Large-Eddy Simulation (DALES) [1] to simulate the June 5, 2013 case in order to:

  • study the effect of spatial resolution of the model to cloud representation.
  • study the effect of driving meteorological fields on the model’s output.
  • examine the effect of parameters such as the cloud condensation nuclei number and the incoming solar radiation in the simulated scenarios.
  • understand different strategies for model - measurement comparison: direct comparison physical quantities and forward operator that simulates the raw instrument reading.

[1] Heus, T., van Heerwaarden, C. C., Jonker, H. J. J., Pier Siebesma, A., Axelsen, S., van den Dries, K., Geoffroy, O., Moene, A. F., Pino, D., de Roode, S. R., and Vilà-Guerau de Arellano, J.: Formulation of the Dutch Atmospheric Large-Eddy Simulation (DALES) and overview of its applications, Geosci. Model Dev., 3, , doi:10.5194/gmd-3-415-2010, 2010.

pictureJune-43.png

Caption: 3D rendering of cloud forming in the simulated domain for 11:00 UTC, 5th June 2013. The colors on the horizontal plane represent the Liquid Water Path (LWP) over each column.