The purposes of this paper are to examine the regionality and seasonal changes of the daily precipitation distributions of Korea and to clarify that's relationship to the location of the front in 128E for the Changma season (early summer rainy season). At first we classify the distribution patterns of the daily rainfall as the northern-part type, the south coast type, the central-part type and the northeast-coast type for June and July, 1982-1989 and then examine their seasonal changes. After that, we take the latitudinal locations of the front (Baiu or Changma front) in 128E and check the relationship of the front locations and the rainfall distribution in terms of the frequencies of the rainfall distribution patterns and the average precipitation for a front location.
The results of this paper are as follows
1) The heavy rainfall type (with daily rainfall more than 80mm) and the northern-part rainfall type are appeared frequently in July, the northeast-coast rainfall type is appeared frequently in former half period of June and the south-coast rainfall type does not show apparently the seasonal change.
2) There are some latitudes where once the front go north, the rainfall pattern of Korea is changed apparently. These are 30N, 33N, 39N and so forth. In orher words, when the front locate south of 25N, there are appeared frequently the no rainfall type, the south-coast rainfall type and northeast-coast rainfall type of little precipitation (less than daily rainfall 10mm or 10-40mm). As the front is shifted northward, there are increased the south-coast rainfall type of much precipitation (more than daily rainfall 80mm or 40-80mm). When the front locate over Korean Peninsular (35-39N), there are appeared frequently the northern-part rainfall type and the central-part rainfall type of much precipitation (more than daily rainfall 80mm or 40-80mm).
3) From the fact that the mean precipitation of the Northern part for a front over Korean Peninsular (35-39N) are much more than that of the Southern coast for a front over the Southern coast of Korea (33-35N), we can explain that the much precipitation area of the Northern part of Korea are located far north from the Changma frontal zone. That is, near the Southern coast there are more fronts but there are less precipitation, in the Northern part less fronts make more rainfall. In these results, over the Northern part of Korea far from the frontal Zone there are formed the much precipitation area in July.

View full abstract

This paper discusses the slope development of valley-head area in the hills around Karumai, northern margin of the Kitakami Mountains, where tephrochronological method is applicable. Each valley head area is classified into six micro-landform units, and the relation between slope profiles and slope surface deposits is investigated by digging a lot of pits. These profiles (Figs. 5, 8) reveal the change of slope processes since the late Last Glacial as follows.
In the Full Glacial, almost all slope in this area including “Crestslope” and “Upper sideslope” suffered surface denudation under periglacial conditions, although small surface slides occured on steep sideslopes in part. In the Late Glacial, surface denudation became weaker as warming climatic condition, and the both slope units were stabilized before HP fall (12-13×10³yr. B. P.). On the other hand, the stabilization of “Lower terrace-like gentle slope”, that is valley bottom in the Last Glacial period, took place in the time between HP fall and NbP fall (8.6×10³yr. B. P.). This stabilization is a consequence of the formation of “Lower sideslope”, that is provided by increase in precipitation.

View full abstract

[in Japanese]

View full abstract