The relation of temperature and velocity to the slope of the tropopause in a steady zonal wind field is derived in spherical polar coordinates. Then, the tropopause “dip” just north of the jet streams in the westerlies is discussed. The relation of temperature and velocity to the slope of the tropopause in a geostrophic wind field was first derived by V. Bjerknes.(1) Further the relation of temperature and velocity to the slope of the tropopause in a gradient wind field was given by H. Ertel.(2) The case treatd by H. Ertel is admittedly a simple one, so it may not be adequate for the problem of the tropopause funnel. However, such a consideration will be of value as a preliminary to the discussion of a steady zonal wind field, though it must be admitted that the analysis will not be essentially new from that given by V. Bjerknes. The upper sign gives when r=∞, so yields a solution which is continuous near straight isobars, while the lower sign gives an arrangement which is not available in the earth's atmosphere. Thus the only solution of Eq. (3 b) which can be extended out to a region of straight isobars is given by Thus the slope of the tropopause is generally steeper than the slopes of near-by isobaric surfaces in the temperate latitudes of the northern hemisphere. Several recent papers from the University of Chicago have attempted to infer the vertical circulation pattern associated with well developed jet streams in the westerlies. _??_f there is to be a finite wind maximum, it is necessary that near the jet centre the slope of the isobaric surfaces steepens and above the jet centre the slope of the isobaric surfaces decreases upward. Since the atmosphere preserves hydrostatic equilibrium to a high degree of approximation, the meridional temperature gradient above the jet stream core must be opposite in direction from that of the lower levels. Thus, well developed jet streams are likely to happen in the region of the tropopause. Isobaric surfaces and the tropopause with steep slopes will be associated with the jet core in the westerlies. Thus, the tropopause dip will be found just north of the jet stream.
1. Secular change of the climate in Sakai on the Japan Sea coast of Chugoku District, Japan. (1) The climate of the period 1925 to 1946 (say the latter period) differs discontinuously from that of 1903 to 1924 (say the former period). (2) The duration of sunshine, the depth of deepest snowfall and the amount of evaporation are increasing, but, on the contrary, the humidity, the number of days without sunshine and that of stormy days are decreasing in the latter period than the former. (3) The increase of the duration of sunshine is largest in summer, and the decrease of humidity and the number of stormy days are largest in winter. 2. Secular change of the climate in other parts of Japan. (1) The climate of all parts of Japan shows a change between these two periods. (2) The change of the duration of sunshine has a tendency to decrease in the sunnyregion along the Pacific coast and to increase in the cloudy region along the Japan Sea coast. The humidity has a tendency to increase in the low humidity region along the Pacific coast and to decrease in the high humidity region along the Japan Sea coast.
The authors analysed the rain water fallen in Nagoya City during January, 1948 and November, 1949, and determined its chloride content. They studied the relation between the chloride content and the course of the air mass that brought the rain. The courses of air masses were classified as follows: a. North China-Yellow Sea-Korea-Japan Sea-Honshu. b. Central China-East China Sea-Honshu. c. Central China-East China Sea-Pacific Ocean-Honshu. d. Bonin Islands-Honshu. The chloride content shows its maximum for the maritime air mass (course d) which comes from the Pacific Ocean. The air mass of the continental origin (course a) shows the least chlorinity which seems to increase with the degree of modification caused by maritime effects.