In recent years it has become obvious that two large ice sheets in Antarctica and Greenland are most ideal medium for past some 100k year record of global climate and environment. Compared with deep-sea sediment, polar ice core has some following advantages as record medium for palaeo-environment. 1) High resolution because of high accumulation rale, 2) High Accurcay because of inactive chemical at ice sheet surface, and 3) Occulusion of air itself by the process of densification from firn to ice. Recent polar ice core studies have revealed 100 k-year cycle of climatic change and the synchronism between Northern and Southern Hemisphere. French and Soviet co-studies on Vostok ice core suggest that CO2 change have had an important climatic role during the late Pleistocene in amplifying the relatively weak orbital forcing. Thus ice core studies have provided fundamental information for the interpretation of glacial and interglacial climatic cycle. Furthermore, such studies on long term climatic changes basis on ice cores show the necessity of interdiciplinary interpretation on atmosphere-ocean-cryosphere climatic system and its relation to earth's orbital movement. Climatic cycle shorter than 100k-year shows regional characteristics. Hypsithermal, the warmest thousand years in Holocence appears in different ages; 8, 000-4, 100 years B. P. for Camp Century, Greenland core, 8, 000-4, 500 years B. P. for Byrd core, (9, 000)-5, 000 years B. P. for Mizuho core and 11, 000-8, 000 years B. P. for Dome-C core, Antarctica. So dose “little ice age”, the recent cold centuries. Polar ice cores reveal large volcanic eruption. Recent studies have suggested the climatic role of volcanic activities; The acidity of Byrd core indicates that a major volcanic event occurred for 150 years just when the transition period from the late glacial to the Holocence started. Thus polar ice core studies release valuable informations on palaeo-climate and environmont. However, further studies are requested for the detailed, quantitative and interdiciplinaly interpretation of 102-105 year climatic variation with high quality deep ice cores. Japanese Antarctic Dome Program at the top of Dronning Maud Land, Antarctica and European Greenland Ice Program (GRIP) are expepected to provide by-polar “standard” cores which will cover more than last climatic cycle.
Rapid deterioration of the West Antarctic ice sheet has been warned, whereas the East Antarctica has been considered rather stable. The Japanese Antarctic Research Expedition, however, revealed that the ice sheet thickness is decreasing at a rate of 0.5 to 0.7m/year in the Shirase drainage. Ice core analyses indicated that the thinning started at ca. 1, 000 years B. P. at around Mizuho Station, which is located about 250km upstream from the coast in the Mizuho Plateau. It is considered that the thinning of the ice sheet should have contributed to the eustatic sea-level rise by about 0.1 m in the last 1, 500 years. A possible trigger and a mechanism of the thinning are hypothesized, and the sea-level rise caused by the deterioration of the West and the East Antarctica is discussed in relation with the cli - matic warming.
Glacier fluctuations during the Holocene in the Himalayas are compared with those in the world. Characteristics of glacier mass balance in the Nepal Himalaya, which belongs to the summer-accumulation type, are described. And the glacier fluctuations after the Little Ice Age in the Nepal Himalaya are discussed on the basis of variation of summer air temperature, which is the controling factor of glacier mass balance in this area.
About 2×109 people live around the Tibetan Plateau and receive much water supply from the snowfall and rainfall over these mountains. Wet monsoon current make continuous and heavy rainfall on the southern side of Tibetan Plateau due to the orographic effect. Sometimes, Indian and Pakistan people are suffered from disastrous floods by these rainfalls. In the upper portion of the Himalayas, monsoon current make much snowfall in the warmer season by the monsoon. The glaciers and snowfields in the Himalayas are thus developed in summer. In the other hand, the snow and ice near the peak of these mountains are melting and supplying water to the rivers in summer. North-western part of the Tibetan Plateau has not so much precipitation in summer, but relatively much snowfall in winter. In this region, water resource is mainly stocked in winter and supply the melting water to the deserts mainly in summer. In this paper, several data are collected mainly from the mountaineering reports, and the mechanism of the water supply around the Tibetan Plateau are discussed.
Sea ice is an important interactive component of the global climate system, affecting reflecting climate change. Therefore, sea ice research is important for climate prediction. Especially important the study on the marginal ice zone in which the polar air, ice and water masses interact with the temperate ocean and climate system. The sea of Okhotsk is the southrenmost freezing sea in the northern hemisphere. Since Hokkaido is situated in its marginal ice zone much more sea ice research is anticipated for climate prediction. There also exists a need explore the social importants of sea ice rese-arch. At present, however, there are less than 10 Japanese scientists in this area of study. It is necessary to further develop this field of study.
The winter snow cover area anomaly over Eurasia has been noted for about a century as a precursor of the succeeding Indian monsoon rainfall anomaly. This snow cover anomaly is shown to be associated with the particular atmospheric teleconnection pattern called Eurasian pattern. Indian monsoon rainfall is shown, in turn, to be tightly linked with the sea surface temperature in the equatoriol Pacific in the following autumn and winter. The global analysis of atmospheric circulation anomalies also demonstrates that the significant Eurasian pattern with anomalous snow cover is greatly responsible for producing anomalous sure gradient along the equatorial Indian Ocean therough the western Pacific, which trigggers the E1 Nino event over the eastern equatorial Pacific. These anomalous condition seem to be caused by the anti-E1 Nino condition over the western Pacific in combination with the polarity of the teleconnection pattern (NAO) over the northern Atlantic through the Arctic region. These observational evidences strongly suggest that the ENSO cycle with a time scale of several year period should be taken as oscillation in the coupled cryosphere/atmosphere/ocean climate system over the globe, rather than that in the coupled atmosphere/ocean system in the tropical Pacific.
It is said that a disaster changes itself as a change in the condition of public life. In Japan, recently with rapid progress of motorization, the traffic accident owing to blowing snow steppes into the spotlight. For example, a multiple pile-up accident on the Expressway appears as a new disaster. As several research studies for blowing snow are carrying out, the disaster due to blowing snow is thought to be reduced in the near future. In this paper, first of all, the outline of the generation of blowing snow and its activity are given in the chapter 1, the relation between snow and wind. Next, the history of prevention of snow disaster on railway and snow problems on road in recent years, are mentioned. In the chapter 3, the investigated results of phenomena generated by snow and wind are introduced. After strong blowing snow, the direction of prevailing wind and the condition of snow cover are estimated with the direction of the wind pattern on snow cover in the area. In the chapter 4, countermeasures against blowing snow and utilization of blowing snow, described are the shape around snow fence, the reconsideration of snowbreak forest and utilization of blowing snow as water resources. In the last chapter, the trends of research studies of blowing snow are introduced, which are being carried forward by the National Research Center for Disaster Prevention and the Civil Engineering Research Institute of Hokkaido Development Bureau.
Heavy snow areas in Japan are located in the central part of the Honshyu Island along the Japan sea, where is warm compared to the Hokkaido and the north part of the Tohoku district. In this report, the disastrous avalanches during the heavy snow fall winters, lately occured in succession in Niigata prefecture, are discussed. The Japanese Islands elongate from north to south, and amount of snowfall and its properties, such as snow are crystals and density is different depending on latitude. Therefore, avalanche release, one of the snow phenomena, is different in time and location. For full-depth avalanches, for example, one peak was found in April in Hokkaido. In Niigata the maximum was in February. The types of disastrous avalanche were dry full-depth slab avalanches and/or dry surface slab avalanche. In high latitude and cold regions, the avalanche release mechanism is weakening of supporing force caused by depth hoar in the middle or bottom layer. However, in Niigata prefecture it was the increase of driving force caused by heavy snowfall. For large scale surface avalanches the weak layer was not depth hoar but a thin wet granular snow sandwiched between dry snow layers. If the wet snow freezes into a dry snow, its strength increased and the surface avalanche could not released on such a slope. Comparisons of simulations of internal frozen in field moving observations revealed that the wet granular snow can be freezed at some situations. Avalanches denude and take in the snow in the steep slope, and sedimentation starts at the gentle slope. The zone of deposit has been morphlogically defined as the zone where snow debris exists. Here, using the mass balance of denudation and sedimentation, a kinematic definition for the zone of deposit was proposed. From observation, for fulldepth avalanches, length of the zone of deposit by both definition was approximately equal. On the other hand, for surface avalanches, the length by the kinematic definition was longer than the morphological one. If the avalanche starts from the same staring zone, the avalanche track in heavy snow winter is longer than the normal year, and track itself is also different. Therefore, catastorophic avalanche disasters occur in the heavy snowfall winter.
Rapid economic growth in post-war Japan resulted in the great change of regionaleconomy and social structure from the late 1950s. As a result of the change, the alleviation of snow problem has become an important subject in the snowy regions. Snow problem is a broader concept than snow damage. It is a comprehensive regional problem includes obstruction of social activities by snow and utilization of snow, which are not necessarily included in snow damage concept. This paper examines historical development and present situation of snow problem, and tries to point out some implications on the necessary conditions of countermeasures for snow problem in future. At first, the changing process of snow problem is summarized, and the signification of the change is examined from the viewpoint of local community. Next, some focal points of snow problem and expected countermeasures are described through an examination on the background and mechanism of contemporary snow problem. The third part is a statistical analysis on regional variations of snow problem, with a consideration of natural and social factors, supposed to be related to the formation of the regional variations. Data from inquiries into 966 municipalities in the snowy area of Japan carried out by National Research Center for Disaster Prevention (NRCDP) during 5 winter periods from 1978/79 to 1982/83 are used in the statistical analysis. The changing process of snow damage and snow problem in Japan can be divided into three historical periods. These periods correspond to an expansion of the contents of snow damage, from a problem of individual safe, to a socioeconomic problem, and finally to a problem of social function. Impact of snow to local communities had been limited to the safety problem for long time, but now it affects almost all social activities. As a result of the change, countermeasures for snow problem are expected to be a structural element of administrative planning system for regional development, not merely a protective measure for natural disaster in a narrow sense. Three focal points of contemporary snow problem are pointed out. These are, obstruction of lifeline functions in winter period, way to suffice the highly advanced requirements of local residents, for example, amenity of winter life, and establishment of organization and manpower to treat snow problem. Regional systematization of snow treatment, improvement of snow resistibility of urban space, and activation of industries and civic life using snow as resources, are also suggested as main targets for administrative organizations correspond to above mentioned problems. Remarkable regional variations are found among the occurrence patterns of various kinds of snow damages and municipal manager's estimation of criticalness about snow problem. The variations mainly correlate with two climatic regional characteristics, namely maximum snow depth in average year and coldness of air temperature in winter period. However, it must be stressed that some social conditions, for instance population of municipality, degree of urbanization, and aged dependency ratio, are playing an important role in the formation of the regional variations. Careful check of the regional variations should be required for administrative policy making and its implementation to counter snow problem. In a concluding paragraph the importance of local community is emphasized as a unit to counter snow problem through systematization of cooperation between administrative organization and local resident.
It is an unavoidable situation, many big cities and towns are located in the heavy snow. fall areas of Japan. A typical cloud pattern over the sea of Japan which will produce a heavy snowfall is shown with the resulting observed snowfall. Variations of the snowpack depth on the ground are shown in space and time. Return periods for the maximum snow depth are shown for five points in Japan. Differences in the depth and stratum of snowpacks at five places in Japan are also shown. The differences of the snow strata and the daily changes are shown from the north to the south for four places in Japan. A survey of snow and ice research in Japan during the past 50 years was carried out along with the activities of the Japanese Society of Snow and Ice. It was revealed from the survey that a wide range of research works on snow and ice have been carried out in the past 50 years. They included artifical snow crystal growth studies, observation of snow crystals in the atmosphere, physical studies of snowpacks, snow accretion on wires and riming studies, mechanical properties of snow and ice, dislocation studies of ice, sea ice studies, frost heaving studies, how to remove or how to prevent snow from railways, runways, roads, roof etc., searches of the best cloth in winters, how plants survive the cold, etc. These scientific or enginnering research works are recorded in “Seppyo”(Japanese Journal of the Japanese Society of Snow and Ice), “Teionkagaku”(Japanese J. issued from the Institute of Low Temperature Science, Hokkaido University) or other journals which are printed from their own research institutes. The number of the papers which were presented in the annual meeting of the Japanese Society of Snow and Ice increased rather dramatically around 1969. Recently the number is approximately 180, because the number of presentations at the annual meeting is limited by the lack of presentation time. Finally, a view of future research works, both in fundamental and applied problems on snow and ice and H2O is presented.