NUCLEATION-DROPLET GROWTH INTERACTIONS AND MICROPHYSICAL PROPERTY DEVELOPMENT IN CONVECTIVE CLOUDS

In the microphysics-dynamics interaction above the convective cloud ba se, the analytic solutions with the Maxwellian droplet growth system o btained by Squires (1958) and Fukuta (1993), without including the rel ationship of the cloud condensation nucleus (CCN) activity spectrum, a re shown to be partial or diagnostic solutions and that of Twomey (195 9) as a complete or prognostic solution within its approximation. The diagnostic solutions of the diffusion-kinetic (DK) droplet growth syst em are numerically evaluated, and significant effects of accommodation coefficients to raise the supersaturation and droplet number concentr ation maxima are found. The relationship among the diagnostic solution , the prognostic solution, and the CCN activity spectrum is graphicall y explained, and a graphical method to obtain the DK prognostic soluti on is described. The prognostic solution with the Maxwellian system ha s been derived in a back-tracking manner and the solution is found to agree with that of Twomey in the functional relationship. The effect o f parameters in the CCN activity spectrum on the maximum droplet numbe r concentration has been assessed for the Maxwellian system. The progn ostic solution of the DK system graphically obtained shows the droplet concentration increase from that of the Maxwellian typically by a fac tor between 1.5 and 2 with condensation coefficient of 0.03 and therma l accommodation coefficient of 1.0.