Impact of wind shear on the top of stratocumulus cloud

In the course of Physics of Stratocumulus Top (POST) campaign CIRPAS Twin Otter research aircraft performed 17 flights in the region of Monterey Bay in July and August 2008. Data analysis revealed two different types of stratocumulus:

(i)„classical”, under strong temperature inversion, dry air above the cloud top and thin wind shear layer in the cloud top region;

(ii)„non-classical” under weak temperature inversion, humid air above and deep shear layer.

In “non-classical” cases conditions prohibit Cloud Top Entrainment Instability. One of such cases (TO13) was used to prepare setup for LES (Large Eddy Simulation). We focus on sources of turbulence responsible for entrainment and mixing process. We perform a series of simulations varying wind shear and radiative cooling in a cloud-top region in order to understand formation of layers in the cloud top region, reported by Malinowski et al., 2013.

Reference: Malinowski, S. P., Gerber, H., Jen-La Plante, I., Kopec, M. K., Kumala, W., Nurowska, K., Chuang, P. Y., Khelif, D., and Haman, K. E., 2013: Physics of Stratocumulus Top (POST): turbulent mixing across capping inversion, Atmos. Chem. Phys., 13, 12171-12186, doi:10.5194/acp-13-12171-2013