Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: S. Chai x
  • Refine by Access: All Content x
Clear All Modify Search
James W. Telford, Thomas S. Keck, and Steven K. Chai

Abstract

The processes involved when dry air is entrained into a cumulus cloud are discussed. The water droplet size spectra are totally changed by this process, as compared to condensation growth in undiluted cloud.

Cloud-top entrainment of dry air is stressed and the difficulties encountered in applying simple past procedures for “homogeneous” and “inhomogeneous mixing” are illustrated. The dynamical constraints on modeling condensation growth are examined. It is concluded that entity type entrainment mixing (ETEM) is the most satisfactory explanation of observed cloud droplet spectra.

Full access
Bjorn Stevens, Donald H. Lenschow, Gabor Vali, Hermann Gerber, A. Bandy, B. Blomquist, J. -L. Brenguier, C. S. Bretherton, F. Burnet, T. Campos, S. Chai, I. Faloona, D. Friesen, S. Haimov, K. Laursen, D. K. Lilly, S. M. Loehrer, Szymon P. Malinowski, B. Morley, M. D. Petters, D. C. Rogers, L. Russell, V. Savic-Jovcic, J. R. Snider, D. Straub, Marcin J. Szumowski, H. Takagi, D. C. Thornton, M. Tschudi, C. Twohy, M. Wetzel, and M. C. van Zanten

The second Dynamics and Chemistry of Marine Stratocumulus (DYCOMS-II) field study is described. The field program consisted of nine flights in marine stratocumulus west-southwest of San Diego, California. The objective of the program was to better understand the physics a n d dynamics of marine stratocumulus. Toward this end special flight strategies, including predominantly nocturnal flights, were employed to optimize estimates of entrainment velocities at cloud-top, large-scale divergence within the boundary layer, drizzle processes in the cloud, cloud microstructure, and aerosol–cloud interactions. Cloud conditions during DYCOMS-II were excellent with almost every flight having uniformly overcast clouds topping a well-mixed boundary layer. Although the emphasis of the manuscript is on the goals and methodologies of DYCOMS-II, some preliminary findings are also presented—the most significant being that the cloud layers appear to entrain less and drizzle more than previous theoretical work led investigators to expect.

Full access