著者

境田 清隆 江越 新 倉持 真之

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.120, no.2, pp.382-391, 2011-04-25 (Released:2011-06-30)

参考文献数

11

被引用文献数

6 9

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The mitigation of the urban heat island phenomenon by local circulations of land and sea breezes has recently become a subject of major interest. This study aims to clarify the effects of sea breezes on the urban heat island phenomenon in Sendai, Northeast Japan, paying attention to the vertical mixing effects of tall buildings. In Sendai city, where the urban heat island phenomenon has developed along with sea breeze circulation, spatially dense observations of temperature were carried out with instrument screens at twenty-five elementary schools in and around the urban area from 2000 to 2004. When a sea breeze begins to blow, the air temperature in the coastal region peaks and does not rise during daytime. By comparing the warming quantity during the day when sea breezes do not blow, the cooling effects of the sea breeze are evaluated quantitatively. It was found that cooling effects are remarkable in May and June, and disappear in September. Cooling effects in the urban center do not differ from those in the suburban area, in spite of dense buildings and large number of roughness parameters. Because of the mixing function, the large number of roughness parameters is considered to be useful to pull the cool air mass of sea breezes down to the ground. Vertical observations of wind and air temperature at the Miyagi Prefectural headquarters, which is located in the central business district (CBD), were carried out from July 2007 to July 2008. When sea breezes begins to blow, downward air currents were observed at the windward walls of buildings, and the cooling effects of sea breezes were identified gradually from the tops of tall buildings to the ground. The horizontal distributions of air temperature during the day with sea breezes produce relatively cool areas near the coast and in the urban center. The cooling effects of sea breezes appear to be more remarkably in the urban center than in the residential area where there are no tall buildings.

著者

内田 和子

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.104, no.4, pp.525-543, 1995-08-25 (Released:2009-11-12)

参考文献数

23

被引用文献数

1

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Japanese flood control was rapidly developed in Modern Ages when regular flood protection works began onnationwide scale. It is flood prevention cooperatives that promoted those public works by bearing a part of the expenses in Modern ages.Flood prevention cooperatives are classified into 3 types according to functions. They are the one that takes a share in the expenses of flood protection works and irrigation-drainage works (type I), the one that practices flood defense activities (type II), and the one that petitions to realize and promote river improvement works and acts a part of the works as an agent of prefecture (type III). The author conducted research on cooperative dues that support activities of cooperatives. The results are as follows.Amount of share in the expenses taken by flood prevention cooperatives much differs in compliance with their functions. In type I cooperative dues were very high, in type II they were less and in type la they were much less. In all types cooperative dues were imposed by standards that based on the degree of flood damages. Especially in type I, much amount of cooperative dues were levied according to many grades, but type II and type III had a few grades. Their objects of imposition were land and houses, and in urban areas they included fabrics such as railroads.Flood prevention cooperatives dissolve when they accomplished their purposes in each function. But the cooperatives of type II shift to public flood defense corporations that consist of municipalities and act by budgets of municipalities.Flood prevention cooperatives fully understood natural features of geomorphology, hydrology and so on, and social features of land use, land ownership, and so on of their areas. On the basis of these recognition they contrived their unique imposition system in consideration of benefit by public flood prevention works. In consequence they promoted public flood prevention works by taking a share in expenses.

著者

本多 光太郎

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.19, no.2, pp.83-91, 1907-02-15 (Released:2010-10-13)

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:18840884)

巻号頁・発行日

vol.11, no.3, pp.234-234, 1899-03-25 (Released:2010-12-22)

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.40, no.7, pp.424-425, 1928

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.11, no.8, pp.589, 1899-08-31 (Released:2010-12-22)

著者

乾 睦子

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.123, no.3, pp.ix-x, 2014-06-25 (Released:2014-07-03)

参考文献数

1

著者

本山 功

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.121, no.3, pp.478-492, 2012-06-25 (Released:2012-07-09)

参考文献数

50

被引用文献数

2 1

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The Benguela Current is an eastern boundary current in the South Atlantic subtropical gyre, associated with strong coastal upwelling off Namibia, which plays a major role in heat transport from the Indian Ocean to the Atlantic Ocean through the Agulhas Current and in the global carbon cycle through high biologic productivity. Seven sedimentary cores (Sites 1081–1087) recovered during the Ocean Drilling Program Leg 175 cruise from continental slopes consist of upper Cenozoic continuous siliceous and calcareous hemipelagic sequences, which allowed high-resolution paleoceanographic analyses over the upwelling region from 20°S to 30°S. Onboard and post-cruise scientific research has revealed and discussed the history of the oceanic system and the relation to global climate changes as follows. (1) Calcareous sequences (Sites 1085 and 1087) in the southern part of the region record sedimentary inprints that can be correlated with the Miocene global carbonate crash events and latest Miocene to early Pliocene biogenic bloom with the first signal of wind-driven upwelling at 11.2 Ma. (2) Off Namibia diatom concentrations dramatically increased after 3.1 Ma and reached a maximum spanning from 2.6 to 2.0 Ma, which was called the Matuyama Diatom Maximum associated with a moderate increase in organic matter accumulation and lowering of sea-surface temperature. This elevated bioproductivity and cooling occurred in response to changes in water circulation caused by gateway closures and enhanced bipolar glaciation. During the last 2 million years, the decreasing trend of diatom deposition coincided with an overall increase of coastal upwelling intensity. (3) The Walvis Opal Paradox is another prominent feature observed in orbitally controlled climate cycles in the upwelling system during the Quaternary. It is characterized by a decrease of diatom/opal deposition, which coincided with increased upwelling during glacial periods and vice versa during interglacials. Its possible causes include waning of North Atlantic Deep Water production during glacials. Despite these great advances in the reconstruction of the evolution of the Benguela Current upwelling system, causal links to global climate and regional events in other oceans are less well understood. To evaluate the interplay between opal/organic carbon deposition in the upwelling system and a series of climatic, tectonic, oceanographic, and biologic events in the world ocean, a better understanding of sedimentary processes on shelves and slopes in terms of glacio-eustatic sea level changes, improvement of paleoproductivity reconstructions, and reevaluation of dissolution of siliceous microfossil shells is needed.

著者

中川 洋 鈴木 麻希 竹内 瑛一 松本 良

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.118, no.5, pp.969-985, 2009-10-25 (Released:2010-03-19)

参考文献数

34

被引用文献数

5 6

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Plantonic and benthic foraminifera are analyzed with 11 sediment cores recovered from the Umitaka Spur area of the Joetsu Basin off Joetsu, Niigata Prefecture. The area is characterized by active methane seeps and methane hydrates. We recognize 12 foraminiferal biozones (Biozone I to XII in descending order) in the last 32000 years based on three selected cores (two well-dated and one longest), and apply them to another 8 cores for correlation. Sediment cores are divided into five lithologic units as massive to bioturbated mud (lithologic unit 1), thinly laminated mud (unit 2), gray massive mud (unit 3), thinly laminated dark mud (unit 4), and bioturbated mud (unit 5) from upper to lower. Lithologic units 2 and 4 correspond to basin-wide thinly laminated layers, previously reported as TL-1 and TL-2, respectively. The Japan Sea became a closed inland basin during the lowest sea level period of the last glacial maximum (LGM) at 27-26cal kyr BP (Biozone VIII). The surface water reached the lowest salinity level, while the bottom water was strongly anoxic due to reduced vertical circulation. An expulsion of a large amount of methane occurred on the Umitaka Spur during the LGM due to a massive dissociation of subsurface methane hydrate. Biozones VIII, VII, and VI at around 27-17 cal kyr BP with planktonic foraminiferal maximum and benthic foraminiferal minimum are found in a dark layer of TL-2, which was formed during the period of the lowest sea level in the LGM. Biozone IV, 12-11 cal kyr BP, is characterized by low oxygen tolerant benthic species of Bolivina pacifica, and correlates with dark layer TL-1, which implies that the deep circulation of Japan Sea was severely reduced for a short period during (or soon after) the Younger Dryas Cooling Event. B III represents the planktonic foraminiferal minimum zone, which marks the transition from cool water species to warm water species in planktonic foraminifera. Foraminiferal stratigraphy reveals that the sedimentation rate of the Umitaka spur sediments varied significantly depending on topography such as pockmarks or mounds.

著者

市原 美恵 Claudia ADAM Valérie VIDAL Pablo GROSSE 三部 賢治 折橋 裕二

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.126, no.2, pp.181-193, 2017-04-25 (Released:2017-06-12)

参考文献数

58

被引用文献数

2 4

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Anomalous arc volcanoes tend to exist where a linear topographic feature (fracture zone, line of seamounts, or ridge) on the oceanic plate is subducting. “Dots-and-lines tectonics” are proposed for clarifying this tendency and understanding the mechanisms that generate it. State-of-the-art studies on along-arc variations of volcanism around the Pacific ring of fire and possible effects of inhomogeneities on the subducting oceanic plate are reviewed. Mechanisms generating the clustered distribution of active volcanoes in North-eastern Japan and the extraordinary volcanism at Mount Fuji are reconsidered from a “dots-and-lines” tectonics point of view. Although there still remain many unsolved problems, “dots-and-lines” tectonics could offer a unified explanation of along-arc variations in volcanism, combining processes in mid-ocean ridges, hot spots, and subduction zones.

著者

新名 阿津子 松原 典孝

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.125, no.6, pp.841-855, 2016-12-25 (Released:2017-01-25)

参考文献数

11

被引用文献数

2 3

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The roles of universities and museums in relation to geoparks are discussed by comparing San'in Kaigan UNESCO Global Geopark in Japan and Lesvos UNESCO Global Geopark in Greece. Bottom-up management is a key to the success of sustainable development. It is important for local people to make decisions on regional matters. Scientists who live in the territory of a geopark are also local people and play multiple roles. They usually work for universities and museums. According to the guideline of UNESCO Geopark, education is an important issue. Geoparks need to connect people with earth science. Educational activities, however, need specific times and places to be carried out. It is essential to provide high-quality educational programs continuously for learners of all kinds in the territory of a geopark. In the case of San'in Kaigan Geopark, individual actors, including administrative officers, local geo tour guides, scientists, and curators provide geopark educational programs for learners without their own geopark educational strategy, because the education committee of San'in Kaigan Geopark discusses school education only and half of the geopark staff members are transferred every year. So, it is not easy for them to take over various tasks of the geopark. This situation in San'in Kaigan keeps learners away from high-quality and continuous education. Under this situation, scientists who work for universities play multiple roles in connecting local people with earth science and other people through multi-scale geopark networks which are of global, regional, national, and local scales, although scientists tend to be rooted and the locations of universities do not necessarily commit scientists to become engaged with the geopark. On the other hand, Lesvos Geopark is a good example. It has a rational educational strategy, develops scientific educational programs combined with geotourism, and provides opportunities for education and employment to local people at the Natural History Museum of Lesvos Petrified Forest. The same staff members at the museum take responsibility for management and education in the geopark. That is why they can develop Lesvos Geopark in a coherent manner.

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.8, no.5, pp.272b-273, 1896

著者

青山千春

出版者

東京地学協会

雑誌

地学雑誌

巻号頁・発行日

vol.118, no.1, 2009

著者

保柳 睦美

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.71, no.5, pp.203-214, 1962-09-30 (Released:2010-10-13)

参考文献数

31

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There are many problems still unsolved in the geographical studies of the Silk Road, which in ancient times connected Asia and Europe culturally and materially.1. Who was the proposer of the name of the Silk Road? Richthofen introduced the term of “Seidenstrassen” in his “China, I”, as well as in the article discussing this route in 1877, and there is no doubt about that Richthofen has popularized the name. The name itself, however, was probably used for the first time in the account of the Greek geographer Marinus of Tyre in about 100 A. D., who had drawn his information from Maes Titianus, a Macedonian silk-merchant who sent agents to China during the 1st century of our era.2. The study of the Silk Road by Richthofen was very instructive and suggestive, in spite of the time in which it was made when detailed maps of Inner Asia were not prepared and the European translation of the Chinese old annals and records were scarce. Although Richthofen's study had some faults, he had a good command of many important Chinese old annals and predicted many of the geographical problems which have been hottly discussed since the early part of the 20th century, based on discoveries made by the scientific expeditions of Sven Hedin and Aurel Stein.(Fig. 1)3. The study by Herrmann was scientifically equipped because of the time in which many European translation of the Chinese old annals and records were prepared and some of the results of the scientific expeditions of Inner Asia were published. The weak point of Herrmann's conclusion, however, lies in that he was too confident in the figures of distance of different oasis states from Ch'ang-an and Wu-lei, given by the Former Han Annals.In ancient times in China, li was not used as one of the official units of distance and was only used as a rough estimate. It was more probable that commonly a day's travel equalled 100li. As a consequence, the assumption of the position of many states and the old road based on the calculation of detailed figures of li of the Former Han Annals was in some parts far from the facts of the past.(Fig. 2)4. The most reliable routes were obtained by the work of Stein, though it is not free from criticism. In the study of the Silk Road, however, it is desirable to begin with the close investigation of topography and other natural conditions along the road.Fig. 3 shows the topography and the distribution of settlements and oases scattered along the margin of the Tarim basin, compiled from the maps prepared by the Army Map Service, Corps of Engineers, U. S. Army (1: 1, 000, 000) and the maps of Chinese Turkestan and Kansu surveyed by Aurel Stein (1: 500, 000). A glance at the map shows that the distribution of large oases are confined to the foot of Tien-shan to the north and to the western half of the foot of Kun-lun to the south. The existence of large oases has close relations with the altitude of mountains and the extent of perpetual snow -field. Rivers nourished by large snow-fields flow down the mountains and have built large oases, such as Aku-su, Kucha to the north and Kashgar, Yarkand and Khotan to the west and to the south. The lands are flat and streamlets branch out, showing the character of delta lands rather than alluvial fans. The present highways run connecting those delta -oases and in ancient times the natural conditions were probably not so different from today.5. Worth noticing, however, is that there scattered many small oases at the apex of the gigantic talus slopes of piedmont gravel, particularly to the southern margin of the basin, attaining in parts a relative height of 1, 500m and more and utterly barren. The path which connects these small talus-apex oases is winding but easy to get water, and even in ancient times it was frequently used as the by-road, particularly between Charchan and Khotan.(Fig. 4)

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.21, no.10, pp.723b-724, 1909

著者

青山 雅史

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.121, no.2, pp.342-358, 2012-04-25 (Released:2012-05-29)

参考文献数

51

被引用文献数

1 1

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Air and ground temperatures on a periglacial smooth slope at Mt. Minamidake (3,033 m a.s.l.), northern Japanese Alps, were observed and used to compare periglacial conditions between alpine areas in Japan and Switzerland. These temperature data were combined with morphometric parameters to discuss periglacial processes forming a bouldery lobe and a pebbly lobe on the smooth slope. Freezing indices at the study site are smaller than indices in permafrost areas of Mt. Fuji and of the Daisetsu Mountains, Hokkaido. Mean annual air temperatures at the study site were within the boundary values for the presence of mountain permafrost. Mean annual ground surface temperatures on the studied slope are comparable to or colder than those at the lower limit of permafrost in the Swiss Alps. Thus, ground surface temperatures on the studied slope indicate the presence of permafrost, unless an advective heat flow such as rainwater infiltration disturbs subsurface temperatures. The bouldery lobe has a smaller riser height than a typical rock glacier, but a larger one than a typical solifluction lobe. The morphometric parameters of the pebbly lobe are comparable to typical solifluction lobes, which originate from annual frost creep and gelifluction. The surface of the bouldery lobe lacks interstitial fine materials, and that of the pebbly lobe is partly composed of a fine debris layer. These conditions suggest that permafrost creep is responsible for the development of the bouldery lobe, while the pebbly lobe originates from annual frost creep and gelifluction.

著者

横山 又次郎

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.24, no.9, pp.608-620_2, 1912-09-15 (Released:2010-10-13)

著者

大場忠道

出版者

東京地学協会

雑誌

地学雑誌

巻号頁・発行日

vol.115, no.5, 2006

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.117, no.6, pp.Cover06_1-Cover06_2, 2008-12-25 (Released:2010-04-26)

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“foss”は滝を表すアイスランド語.Langjökull(jökullは氷河を表す)を起源とするHvítá川の中上流部にあり,氷河に由来する白濁した川が水しぶきをあげて豪快に流れ下る.当地は,アイスランドの代表的な観光ツアーであるゴールデンサークルツアーにも組み込まれており,多くの人々が訪れる観光地である.河岸には,柱状節理や板状節理の発達した溶岩,枕状溶岩を含む角礫岩などがみられ,氷河の下で起こった火成活動の片鱗がうかがえる.目を上げれば,水源であるLangjökullをみることができる.アイスランドを訪れて印象的であったことの一つが水の美しさ.氷河性河川の豪快な流れ,溶岩原に湧き出す清澄な湧水,青白色の温泉水,どれも火山と氷河の国らしい自然の美しさを感じさせる.(写真・解説:金丸龍夫 撮影日2008年8月19日)

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.28, no.11, pp.789a-791, 1916