Abstract
The mass spectra of large and giant hygroscopic particles in the air are measured by means of a hand-operated impactor and a microscope. Our results are in good agreement with the spectra obtained by several investigators at different places of the world. The concentrations of the giant particles are largest on the sea or on the coast and decrease to one tenth at distances of about 100 km from the coast. Further decrease of the concentration is observed at cloud base. These observations suggest that the main source of the giant hygroscopic particles is the ocean.
It is further found that there are enough giant hygroscopic nuclei for the production of drizzle at the stratus cloud base.
