In this paper, the position of geomorphology in the area of geography in Japan and the recent trend of Japanese geomorphology are discussed, judged from the papers published in Geographical Review of Japan (Chirigaku Hyoron). Since the establishment of the Association of Japanese Geographers in 1925, geomorphology has been a main object of study in the field of geography in Japan. Immediately after 1945, geomorphological studies have become conspicuously active in comparison with other fields in the physical geography, and quantitative researches of fluvial and marine deposits such as gravel analysis and the studies of mechanism of the formation of geomorphoic surfaces made rapid progress particularly from 1950 to 1960. At that time, depositional topographies were paid more attention to than erosional topographies. As is well known, the Japanese Islands belong to an orogenic zone showing many topo-graphic features affected by crustal movements in the recent geological periods. Therefore, Japanese geomorphologists have paid much attention to the relationship between landforms and crustal movements. After 1950, active faults have been investigated by many geomor-pholcgists in Japan. Recently, systematic approaches of active faults of Japanese Islands appeared and the result was published as Active Fault of Japan (1985). Around 1960, papers of the geomorphic history in Holocene and Pleistocene were intensively published in Geographical Review of Japan. One of the typical examples of such researches is a study of geomorphic history of the Kanto Plain, which became a standard region of Quarternary Chronology in Japan, using a tephrochronological method. On the other hand, quanti-tative and experimental studies of the external agencies on the depositional and erosional forms are also actively carried out. It is worthy of note that the relations between processes and land forms are precisely examined. At present, notable is the progress of general geomorphology, such as studies on mech-anisms and processes of the formation of landforms, experimental geomorphology, climatic gecmorphology as well as tectonic geomorphology and geomorphic chronology, in Japan. Thus, contents of Japanese geomorphology have a wide variety. However, papers on re-gic-nal geomorphology has been very few, contrary to those on general geomorphology. From the viewpoint of geography in Japan, this tendency is not desirable. In recent years a store of topographic knowledge has been accumulated in various parts of Japan. Japanese geomorphology is now considered to have reached a step to make a systematic regional geomorphology of Japan from a standpoint of geographical philosophy.
The purpose of this study is to clarify the characteristics of blockings appeared in summer over East Asia and the developement or the dissipation processes of the blockings from the view point of stationary Rossby wave propagation. The latitudinal structure of zcnal mean flow at the 500 mb level in summer over Fast Asia during 1946-1985 are classified by means of principal component analysis to result in six types of circulation regimes (1A, 1B, 2A, 2B, 3A, 3B). Among these circulation regimes, two types of regimes, Type 1A and Type 3B, are obtained as blocking patterns. The former appears mainly in June and the first ten days of July and the latter in the middle and the last ten days of July and August (Fig. 2). The former has more strong persistency than the latter (Fig. 4), During the occurrence periods of both blockings, the anticyclone at surface lies over the Sea of Okhotsk and the temperature anomalies are markedly negative all around Japan (Fig. 5 and Fig. 6). The transition probabilities between six types of circulation regimes are calculated. Those which have high transition probabilities are selected, and composite maps for the 500mb level isobaric heights are prepared taking by the circulation regime to appear at next pentad -into consideration. Differences between the composite maps are investigated and the character istic feature about the developement and the dissipation processes for Type IA and Type 3B blocking are found as follows. Type 1A: In the developement stage of blocking, two Rossby wave trains begin to be seen remarkably. One is that which appears high (H) over Atlantic south-western Europe-low (L) over north-eastern Europe→H over the west of Tibet. Another is that which appears L over the east of Tibet→H over the east of Siberia. In the dissipation stage of blocking, the Rossby wave trains having a opposite mark to ones appeared in the developement stage begin to appear. It seems that such stationary Rossby wave propagation contributes largely to the blocking (Fig. 9 and Fig. 10). Type 3B: In the developement stage, Rossby wave train which has its origin in the neighbourhood of Japan, is extended to North America (L near to Japan→H over Aleutian→L over Alaska). On the other hand, the appearance of Rossby wave train occurred from the neighbourhood of Oasipean Sea to Pacific Ocean seems to contribute to dissipation of the blocking (Fig. 11 and Fig.12)