THE OPTICAL-PROPERTIES AND MORPHOLOGY OF CLOUD-PROCESSED CARBONACEOUS SMOKE

The effects of high relative humidity and low supersaturations of water vapour on the morphology of fractal clusters of carbonaceous smoke are examined. Under supersaturation conditions, characteristic of those found in the atmosphere, smoke still consists of fractal clusters, although the fractal dimension has been substantially increased. The result of cloud processing (repeated compression/expansion cycles) upon the optical properties of the clusters indicates little change for small clusters (N < 102) and a much greater effect for large clusters (N > 103 primary spherules). This is qualitatively consistent with the predictions of theory if the particles change from clusters of fractal dimension D < 2 to compact spheres as a result of such processing. © 1990.