Application of the Coupled Dynamical－Radiational Model of Stratocumulus

This paper presents some results concerning applications of the coupled dynamical-radiational model of stratocumulus Ye developed (Ye, 1990, hereafter referred to as the DRS model). Basically, calculations involved here relate to the time-integration of the DRS model to estimate some time constants associated with the boundary layer and cloud developments. To obtain cloud lifetime (CLT), the time interval from its formation to its dissipation, dif-ferent cloud instability criteria are compared, the mechanism for dissipating cloud are discussed, and thereby two new criteria for judging whether cloud can maintain are established. Following these criteria, the sensitivities of CLT to parameters such as the air-sea temperature difference, subsidence, and surface wind are estimated. The main inter-esting results about the sensitivities of the forming time (CFT) are a stable environment, such as cool sea, low wind, and strong subsidence, would prolong the existence of Sc, which has been predicted by the model calculations and strikingly tallies with statistical observations.Besides, with the DRS model and the CLT criteria, we follow a marine boundary layer, starting with clear sky, through the formation and development of clouds and rain, until their dissipation. On the whole, the model results fit the developing process of a typically stable marine boundary layer, and show some features Nicholls (1984) observed for daytime Sc.