Abstract
Graupel showers formed und e r the winter monsoon situation were frequently observed on the coast of Japanese Archipelago along the Sea of Japan. Graupels ranged from 0.2 to 10 mm in diameter, and their shapes were found to be granular in most cases for small graupels less than 2 mm in diameter. Smaller conical graupels were mostly of circular conical form, whereas larger ones have spherical bases. Thus, it was relatively easy for us to make an estimation of their volumes and accordingly their density. Their density was found to range from 0.3 to 0.5g/cm3, with an average of 0.396 g/cm3, irrespective of size in the region, rangeing from 2 to 7 mm in diameter.