With a closed system of prognostic equations, which govern the time change of zonal mean flow, of merdional eddy transport of westerly momentum and of kinetic energy of disturbance, the variation of general circulation in the barotropic nondivergent atmosphere is discussed, including a physical interpretation of barotropic instability. There are three fundamental types in the motion of jet stream: first is the one ex pected in the barotropically unstable state where the jet stream is sharp and corresponds to the phenomenon such as splitting ; second is expected in the barotropically stable state where the jet stream is flat and the motion is mainly affected by the latitudinal distribution of kinetic energy of the disturbance; the third is characterized by the alternate oc currence of the first and the second. Results of tentative prediction of zonal mean flow are shown.
An analysis of small-scale disturbance followed by severe storms was performed by making use of the automatic recording data of weather stations in western Japan and South Korea. A high pressure cell with 500km length and 50km width could be pursued for about 12 hours from South Korea to the central Japan. Mesomaps were constructed in order to study the mechanism of the maintenance of the squall line and to estimate the order of magnitude of each term in the equation of motion governing the phenomena.
Crystals of some benzenoid compounds are found to have abilities of ice nucleation in a laboratory experiment. Terephthalic acid and phthalic acid are superior to the most effective silicate minerals in that ability. Formation of hydrogenbonded linkage between water molecule and carboxyl group is suggested to be an origin of their property of ice nucleation. Possible meteorological significance of organic ice nuclei for the formation of rainfall in maritime airmasses is discussed.