Within the theory of spatial interaction modeling, the competing destinations model is the first ray of hope for a solution of the misspecification problem which states that the estimated distancedecay parameter might be biased by the spatial structure effect of the system under consideration. However, the underlying idea of the two-stage destinationchoice process, which the model assumes, has not been empricially verified. This paper tackles the issue by examining the estimated parameter on the inclusive value of the nested logit model, which is conceptually equivalent to the competing destinations model. The results obtained in terms of outmigration from each of the 46 prefectures in Japan are sufficient to verify the process. In addition, the effect of different choice trees on the model performances is discussed.

View full abstract

In this paper, the author examines the water supply and drainage systems of Tokyo, Mexico City, Paris and Sdo Paulo. Through a comparison of the former two cities, we recognize the difference between an advanced city and a primate city in a developing country. To this schema, Paris, another advanced city, and Sao Paulo, one more primate city in a developing country, are added, to give an extra dimension to the observation.
As the main point of view, an analysis of the historical development of the water supply and drainage systems is done. Then, the diffusion of the systems and their maintenance in terms of working order are examined in each city.
In conclusion, the author has placed these four cases in the schema of advanced cities and primate cities of developing countries. But the meaning of “advanced” is expressed in a different way in the cases of Tokyo and Paris, and on the other hand, Mexico City and Sdo Paulo have their own ways of development, although they show the same kinds of problems, which are characteristic of primate cities in developing countries.
The process of development represents the history of the necessity of their installations, which appear as a result of the convergence of social conditions with physical ones.

View full abstract

The Xishuangbanna (_??__??__??__??_) Dai Nationality Autonomous Prefecture is located at the end of the southwest part of the People's Republic of China. It borders on Burma and Laos. The tropical areas including Xishuangbanna, Hainan Island etc. in China are marginal tropial areas when compared to the typical humid tropical areas like Malaysia and Indonesia and other places in Southeast Asia.
In Xishuangbanna, we can find over eleven minority ethnic groups including Dai, Jinuo etc. and they practice many types of agriculture. In this paper, the authors discuss the characteristics and recent changes in agricultural land use and crop cultivation according to nationalities on the basis of the authors' field work.
In the 1980's, a Responsibility System for Agricultural Production was introduced in Xishuangbanna, and they are carrying out agricultural changes that they have never undertaken before. This is centered on the expansion of modern and intensive agriculture of rubber, tea and tropical fruits. Rubber tree growing has been introduced by many minorities, and the height limit of rubber tree growing is 1, 350 meters above sea level.
In general, through the process of modernization in agriculture, the introduction of rubber and tea, the paddies in the basins and the slash and burn cultivation in the mountain regions have been receiving little attention in their agriculture. The result is that their cultural characteristics tend to slowly decline especially among the minorities who are non-Buddhist. We find that the minorities show a tendency to adapt to the Han people's culture.

View full abstract

From the viewpoint of floristic geography, Yunnan and Hainan like other areas in South China are transitional areas between Holarctic and Palaeotropic Floral Kingdoms. Accordingly, plants of both floral kingdoms are mixed together. Besides, there are many indigenous taxa of plant.
Physical conditions, especially in Yunnan, are very complicated; local differences in habitats are great. Thus, various types of plant communities are found from tropical rain forest to arctic vegetation in summit areas. Special interest is paid to sclerophyllous oaks and their communities.

View full abstract

In Xishuangbanna, Yunnan Province, zonal soils are vertically distributed as follows: Quasi latosol (below 600 m a. s. l.), Lateritic red earth (600-900 m a. s. l.), Red earth (900-1, 600 m a. s. l.) and Yellow brown soil (above 1, 600 m a. s. l.). However, Lateric red earth is also found as a palaeosol in the Red earth zone. The crystallinity ratio (Fe_d-Fe_o)/Fe_t of iron was calculated from the results of of chemical analysis for each soils: for Quasi latosol it is over 0.85 in most cases, between 0.7 and 0.85 for Lateritic red earth, and from 0.5 to 0.7 for Red earth.
Based on KIRA's Warmth Index, areas in Xishuangbanna below 900 m a. s. l. are classified as subtropical, while those above that level belong to the warm temperate zone. But while Red soil is found in the subtropical zone, Yellow brown forest soil as well red soil as palaeosols are widely distributed in the warm temperate zone in Southwest Japan. Thus the relationship between the Warmth Index and the soil type in Yunnan, South China is different from their equivalent in Southwest Japan. However, the iron crystallinity ratio of the Red earth in Yunnan and the Red soil in Southwest Japan lie almost within the same range (0.5 to 0.7).
The southern part of Yunnan Province lower than 600 m a. s. l. is subtropical according to KIRA's Warmth Index, but, Quasi latosol distributes in Xishuangbanna. In this region, d (water deficiency based on THORNTHWAITE's 1948 definition) occurs every year between January and June. Generally, in Guangdong Province, eastern South China, does not occur every year from January to June. In contrast, it occurs annually in August and September in eastern South China. The southern part of Yunnan Province has high temperature with humid climate in summer, a favorable condition for the decomposition of organic matter. On the other hand, winter and spring have mild weather and drought occurs every year. It is believed that this climatic condition encourages the crystallization of iron and as a result, Quasi latosol and Lateritic red earth are distributed even though the thermal condition is subtropical. However, there is still the possibility that Quasi latosol may be distributed as a palaeosol in this area.

View full abstract

Observations on cold air lakes and fog were made in the Jinghong and the Mengyang basins in Xishuangbanna, Yunnan Province, China during the cold fog seasons, 1986-87 and 1988- 89. A great change of temperature profile occurs in the lower layer of the basin atmosphere at fog formation. During the pre-fog period an inversion layer, that is a cold air lake, develops. However, the inversion in the lower layer disappears at fog formation and then an unstable profile is formed.
The development of the inversion layer and the unstable air are strongly influenced by the topographical environments in the basins. Therefore, the night-time variation of temperature profile is different between the basins. Because the development of the fog layer relates to the temperature profile, differences in the life cycle of fog are also seen between the basins. Furthermore, it is suggested that the meso-scale circulation system participates in the development of cold air lakes and fog formation.

View full abstract

The present paper deals first with conditions of air temperature, rainfall, fog, sunshine hours, winds etc. and secondly their impact on the cultivation of rubber, tea, rice, sugarcane etc. Cold waves occur not infrequently, causing serious damage to the tropical crops mentioned above. Favorable temperature conditions apart from winter and summer on the slopes are found in the zone between 1, 300m and 1, 650 m a. s. l. The bottoms of valleys and basins have different conditions from the surrounding mountain slopes, which may be utilized for different crop cultivation or for a different harvesting season. Spring drought is serious in some years. Irrigation is needed as a countermeasure.

View full abstract

The dominant time-space structure of cold surges affecting Yunnan Province and the whole of China are investigated by applying an empirical orthogonal function (EOF) analysis of monthly surface temperature anomalies for the winters of 28 years (1959-1986). It has been revealed that the predominant mode for Yunnan Province is part of the cold surge over the eastern periphery of the Tibetan Plateau through the coastal area of the southernmost part of China. The predominant mode for the whole of China affects most parts of China particularly to the south of 40°N centered near the Yangtze River basin, but its influence upon Yunnan Province is small. The atmospheric circulation patterns associated with these two modes are deduced by producing composite charts of 500 mb height and sea level pressure anomalies in the Northern Hemisphere. The pattern for the dominant mode of Yunnan Province shows the so-called Eurasian pattern with the anomalous trough over central Asia, and the North Atlantic Oscillation with negative polarity over Greenland. The pattern for the dominant mode over the whole of China seems, in contrast, to be more directly related to the outbreak of a cold air mass over the eastern part of the continent.

View full abstract

The geographical distribution pattern of zonal soils in Hainan Island, China is rather complicated, because the island is located in the transitional zone from subtropics to tropics and humidity decreases from the east to the west. In order to elucidate the taxonomical position of the zonal soils of the island, three representative soil profiles of Latosol, Lateritic red earth and Ferric latosol were selected to analyze general chemical properties, clay-mineralogical composition and the mode of existence of iron compounds. Based on these properties correlation with the categories in the U. S. Soil Taxonomy, FAO/Unesco sytem and the ecological soil classification system of France was made. The results obtained are as follows:
1) The Latosol under subtropicl or tropical monsoon forest climate with 5 months of dry season is correlated with Oxic Rhodustalf (USA), Chromic Lixisols (FAO/Unesco) and Typical Tropial ferruginous soils (France).
2) The Lateritic red earth under subtropical monsoon forest climate with 4 months of dry season is correlated with Oxic Haplustults (USA), Haplic Alisols (FAO/Unesco) and Tropical ferruginous soils with low base saturation (France).
3) The Ferric latosol under subtropical or tropical rain forest climate is correlated with Tropeptic Haplorthox (USA), Rhodic Ferralsols (FAO/Unesco) and Ferrisols (France). Consequently, the so-called Latosol and Lateritic red earth of Hainan Island do not belong to the category of true Latosols, viz. Oxisols or Ferralsols; only the Ferric latosol is barely considered to belong to true Latosols.

View full abstract

Micrometeorological properties of rubber tree plantation were measured for three years from April 1986 to March 1989 in Hainan Island. Aerodynamic properties such as the effective height, the roughness parameter and zero-plane displacement and the penetration rate of radiation through the rubber tree canopy were clearly changed with fall and elongation of leaves and stems of rubber tree. Albedo of short-wave radiation above the canopy also changed from 10% in winter and spring to 16% in summer and autumn. The latent heat flux above the canopy have decreased drastically after leaf fall and sensible heat increased. The sensible heat flux on the forest floor was very small.through the day. Heat loss due to negative net radiation was compensated by the soil heat flux during the night.

View full abstract