Rupture nucleations in the 1995 Hyogo-ken Nanbu earthquake and its large aftershocks   总被引：1，自引：0，他引：1  

Bunichiro Shibazaki  Yasuhiro Yoshida  Mamoru Nakamura  Masao Nakamura  Hiroshi Katao 《Geophysical Journal International》2002,149(3):572-588

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Microbiological and Chemical Studies in the Seas of Hiuchi and Bingo—II     

Yoichi Yoshida  Masao Kimata 《Journal of Oceanography》1970,26(1):6-10

The distribution of inorganic nitrogen compounds and the metabolic rates of these compounds by microorganisms as a whole were investigated in the Seas of Hiuchi and Bingo. The results obtained are as follows:

1. Of inorganic nitrogen compounds, the contents in sea water, those in bottom muds, the uptake or liberation rates of microorganisms as a whole in sea water, and the liberation rates from bottom muds to sea water are 0.2～4.0 μg at. N/l, 3～60 μg at.N/100 g, 0.01～0.5 μg at.N//lhr, and 0.3～1.9 μg at.N/100 cm²/hr, respectively, and these contents or rates of ammonia usually are the largest of these inorganic nitrogen compounds.
2. From the above-mentioned results and the others, it is suggested that the nitrogen in the seas circulates mainly in sea water itself and the course of nitrogen cycle, which passes through bottom muds, is not so important, and further that, of the cycle of inorganic nitrogen compounds, the main course is the course which ammonia is liberated from organic nitrogen compounds and it is immediately uptaked by microorganisms, and the course which it is oxidized to nitrate and the others are not so important.

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Specific accumulation and temporal trends of organochlorine contaminants in Dall's porpoises (Phocoenoides dalli) from Japanese coastal waters     

Kajiwara N  Watanabe M  Tanabe S  Nakamatsu K  Amano M  Miyazaki N 《Marine pollution bulletin》2002,44(10):1089-1099

Organochlorine compounds (OCs) such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane related compounds, hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), tris(4-chlorophenyl) methane (TCPMe) and tris(4-chlorophenyl) methanol were determined in the blubber of Dall's porpoises (Phocoenoides dalli) collected from Japanese coastal waters in 1998/1999. Among OCs analyzed, PCBs were the predominant contaminants with concentrations ranging from 1.5 to 39 microg/g on a wet weight basis. OCs concentrations were relatively low and less variable in mature females possibly due to the lactational excretion from their bodies, while in males the concentrations were increased with body length. Concentrations and compositions of DDTs and HCHs showed significant differences between the truei-type population off the Pacific coast of northern Japan and dalli-type from the Sea of Japan/Okhotsk, suggesting its usefulness to discriminate different populations. OCs levels detected in truei-type porpoises collected in 1998/1999 were lower than those collected in 1984, except TCPMe. On the other hand, except DDTs, the residue levels of other organochlorines in dalli-type porpoises showed no significant decrease since 1984.  相似文献   

The Carbon Cycle of Sandy Lands in China and its GlobalSignificance   总被引：1，自引：0，他引：1  

Feng Qi  Cheng Guoduong  Mikami Masao 《Climatic change》2001,48(4):535-549

The quantitative C dynamics of desertifiedlands in Northern China were predicted for the years2000 and 2030, based on the areas and conversion rates(positive and negative) of desertified lands in thepast forty years and organic carbon contents of soils.The top 1.0 m soil layer of natural desertified landsin China contained some 7,841 Tg of organic carbon asof 1992. In China, over the last 40 years, a total of2,812 Tg of organic carbon was released from desertlands and, in the reverse process about 644 Tg oforganic-C were fixed into lands undergoingdesertification. Thus, China's desert lands have showna net release of 2,168 Tg of organic-C over the past40 years, equivalent to 7,949 Tg of CO₂. By theyear 2000, the area of desertified lands in China hadincreased 40,300 km² and released 368 Tg oforganic-C into the atmosphere. By 2030 this area willincrease to 249,700 km² and release about 1,996 Tg of organic-Cinto the atmosphere. Net releases of151 Tg and 1,243 Tg of organic-C can be expectedby the year 2000 and 2030, respectively. This wouldbe equivalent to a net release of 553 Tg of CO₂by 2000 and 4,558 Tg by 2030. Thus, the organiccarbon released through land desertification in Chinacould be an important factor affecting changes inconcentrations of greenhouse gases worldwide.  相似文献   

Heterogeneous Saltation: Theory, Observation and Comparison   总被引：7，自引：0，他引：7  

Yaping Shao  Masao Mikami 《Boundary-Layer Meteorology》2005,115(3):359-379

In the theory of saltation, under development since the 1940s, it is often assumed that saltation is homogeneous, i.e., saltating particles are uniform in size and follow identical trajectories. This assumption is a limitation to the development of saltation theory. In this paper, as in some other studies made since the 1980s, we are concerned with the saltation of multi-sized particles in turbulent flows, a process that we refer to as heterogeneous saltation. The theory deals with several questions, including the variation of particle size distribution with height, the entrainment rates of particles in different size ranges, and the associated profiles of saltation flux, particle momentum flux and particle concentration. It is hypothesised that saltation is dynamically similar and ‘universal’ similarity functions can be established. The similarity function for saltation flux is presented. Field observations are carried out at the southern fringe of the Takla Makan Desert in April 2002. Measurements of streamwise saltation flux of 32 particle size groups are made using a sand particle counter, together with measurements of wind speed and other atmospheric variables. These data are used to validate the saltation theory, by examining whether the observed saltation flux and particle size distribution can be reproduced. It is shown that the theory is promising in predicting these quantities.  相似文献   

Decadal variability of Subtropical Mode Water subduction and its impact on biogeochemistry     

Eitarou Oka  Bo Qiu  Yusuke Takatani  Kazutaka Enyo  Daisuke Sasano  Naohiro Kosugi  Masao Ishii  Toshiya Nakano  Toshio Suga 《Journal of Oceanography》2015,71(4):389-400

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Hypoxia in Manila Bay, Philippines during the northeast monsoon     

Jacinto GS  Sotto LP  Senal MI  San Diego-McGlone ML  Escobar MT  Amano A  Miller TW 《Marine pollution bulletin》2011,63(5-12):243-248

Herein we present results from one of the first extensive bay-wide oceanographic surveys of Manila Bay, wherein 31 stations were sampled during the northeast monsoon (cold and dry season). A band of hypoxic bottom water (dissolved oxygen<2.8 mg/L) spanned the midsection of the bay from east to west. Bottom nitrate concentrations (5.7-16.8 μM; avg. 11.1 μM) and total organic carbon values in sediments (1.7-3.1%; avg. 2.4%) were high in the midsection, which coincided with the band of hypoxic bottom water. Physical processes and site-specific accumulation of organic material likely lead to hypoxic conditions in Manila Bay, even during the northeast monsoon period when the water column is relatively well mixed. The results of this study complement the previously reported widespread hypoxia that occurs during the rainy season. Thus, hypoxia may be pervasive in the bay throughout the year, although it varies in intensity and spatial extent.  相似文献   

Statistical re-examination of reported emission lines in the X-ray afterglow of GRB 011211     

Robert E. Rutledge  Masao Sako † 《Monthly notices of the Royal Astronomical Society》2003,339(3):600-606

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Surface water chemistry and nitrate pollution in Shimabara,Nagasaki, Japan     

Hiroki Amano  Kei Nakagawa  Ronny Berndtsson 《Environmental Earth Sciences》2018,77(9):354

Groundwater is a finite resource that is threatened by pollution all over the world. Shimabara City, Nagasaki, Japan, uses groundwater for its main water supply. During recent years, the city has experienced severe nitrate pollution in its groundwater. For better understanding of origin and impact of the pollution, chemical effects and surface–groundwater interactions need to be examined. For this purpose, we developed a methodology that builds on joint geochemical analyses and advanced statistical treatment. Water samples were collected at 42 sampling points in Shimabara including a part of Unzen City. Spatial distribution of water chemistry constituents was assessed by describing Stiff and Piper diagrams using major ions concentrations. The nitrate (NO₃?+?NO₂–N) concentration in 45% of water samples exceeded permissible Japanese drinking level of 10 mg L^??1. Most of the samples showed Ca–HCO₃ or Ca–(NO₃?+?SO₄) water types. Some samples were classified into characteristic water types such as Na–Cl, (Na?+?K)–HCO₃, (Na?+?K)–(SO₄?+?NO₃), and Ca–Cl. Thus, results indicated salt water intrusion from the sea and anthropogenic pollution. At the upstream of Nishi River, although water chemistry was characterized as Ca–HCO₃, ion concentrations were higher than those of other rivers. This is probably an effect of disinfection in livestock farming using slaked lime. Positive correlation between NO₃^? and SO₄^2?, Mg²⁺, Ca²⁺, Na⁺, K⁺, and Cl^? (r?=?0.32–0.64) is evidence that nitrate pollution sources are chemical fertilizers and livestock waste. Principal component analysis showed that chemistry of water samples can be explained by three main components (PCs). PC1 depicts general ion concentration. PC2 and PC3 share influence from chemical fertilizer and livestock waste. Cluster analyses grouped water samples into four main clusters. One of these is the general river chemistry mainly affected by PC1. The others reflect anthropogenic activities and are identified by the combination of the three PCs.  相似文献   

Tectonic shortening and coeval volcanism during the Quaternary, Northeast Japan arc     

Koji Umeda  Masao Ban  Shintaro Hayashi  Tomohiro Kusano 《Journal of Earth System Science》2013,122(1):137-147

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