白鱀豚哨叫声的研究   总被引：1，自引：0，他引：1  

王丁  王克雄  赤松友成  藤田薰 《海洋与湖沼》1999,30(4):349-354

于1996年1月,在中国科学院水生生物研究所白暨豚馆人工饲养池和湖北省石首市天鹅洲长江故道,使用频响范围分别为0－100kHz和0－16kHz的磁带记录系统,记录了一头成年雄性和一头成年雌性白暨豚的哨叫声。采用计算机信号分析系统详细分析了哨叫声的结构和声谱图,并与其它鲸类哨叫声进行比较。结果表明,白暨豚哨叫声的最大和最小频率平均值分别为5841Hz和4975Hz,频率变化幅度一般小于1000Hz。哨叫声平均持续时间为907ms。频率随时间变化不连续,且较平缓,起伏很少,有部分重叠现象。白暨豚哨叫声的结构与另一种淡水豚─—亚河豚相近,但相对于一些海洋性种类（如宽吻海豚）则呈现较大的差异,表现出对环境的高度适应性。  相似文献   

Zoned Calc-Alkaline Plutons in Northeastern Kamchatka,Russia: Implications for the crustal growth in magmatic arcs     

P. K. Kepezhinskas  I. Reuber  H. Tanaka  S. Miyashita 《Mineralogy and Petrology》1993,49(3-4):147-174

Summary The Upper Cretaceous oceanic and island-arc terranes of Northeastern Kamchatka (Russia) are intruded by numerous ultramafic and mafic to intermediate plutons. Ultramafic plutons north of Epilchik Lake show a concentric structure: dunites in the core pass progressively outwards into wehrlites and pyroxenites and into gabbros along the rim which are occasionally phlogopite- and amphibole-bearing. Compositional layering and mineral orientations marked by spinel clusters in the dunites and by acicular amphiboles in the marginal gabbros are parallel to the contacts. The mafic to intermediate plutons studied in the Machevna area show similar concentric structure with a dioritic core and a gabbroic rim. Magmatic flow lines are near-vertical in the central part of the plutons. These internal structures and general geometry of the plutons suggest vertical magma intrusion into mega-tension gashes developed initially at a high angle to the subduction zone.Olivine, pyroxenes, and plagioclase have primitive compositions. Al-rich, highpressure amphiboles are followed by Al-poor, low-pressure hornblendes. A two stage model of pluton crystallization and emplacement is proposed: initial crystallization and seggregation at the Moho level below the intraoceanic island are (approximately 22–25 km depth) and final emplacement followed by partial recycling of primary ultramafic cumulates and solidification at upper crustal levels (approximately 8–10 km depth). Emplacement of the arc plutons was accompanied by epidote amphibolite-facies contact metamorphism of host volcanic and pyroclastic rocks.Major- and trace-element analyses of plutonic rocks indicate calc-alkaline affinities and emplacement in a primitive arc setting. The tectonic setting, age, and emplacement structures suggest that these plutons mark the change of geodynamic conditions from arc-related compression to local extension probably related to the initial stages of opening of the proto-Komandorsky basin. A two stage model for the crustal growth in magmatic arcs is proposed based on northeastern Kamchatka plutons. During stage I, primitive basaltic melts were emplaced along the crust-mantle boundary below the arc. Continuous fractionation and accumulation of olivine-rich cumulate rocks at the base of the growing island-arc crust resulted in production of evolved melt which was further emplaced in the upper arc crust. Crystal fractionation of a shallow, stage II magmatic reservoir below the active arc volcanoes resulted in formation of a significant amount of plutonic rocks and eruption of mafic to intermediate calc-alkaline lavas at the surface.

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Zonierte kalk-alkalische Plutone im nardöstlichen Kamchatka, Russland: Hinweise auf Krusten Wachstum inmagmatischen Bögen

Zusammenfassung Zahlreiche ultramafische, Bowie mafische bis intermediäre Plutone intrudieren die oberkretazischen ozeanischen und Inselbogen-Terrains in Nordost-Kamchatka (Russland). Ultramafische Plutone nördlich des Epilchik Lake zeigen eine konzentrische Struktur: Dunite im Kern gehen graduell in Wehrlite und Pyroxenite, und schließlich am Rand in Gabbros über, die gelegentlich Phlogopit und Amphibol führen. Lagenbau und Orientierung von Mineralkörnern sind durch Spinell-Kluster in den Duniten und durch nadelige Amphibole in den randlichen Gabbros gekennzeichnet und liegen parallel zu den Kontakten. Die mafischen bis intermediären Plutone in dem Machevna-Gebiet zeigen ähnliche konzentrische Strukturen mit einem dioritischen Kern und einem gabbroischen Rand. Magmatische Flußlinien Bind fast vertikal in den zentralen Teilen der Plutone. Diese internen Strukturen und die allgemeine Geometrie der Plutone legen es nahe, daß es sich hier um vertikale Magmen-Intrusion in Mega-Strukturen handelt, die sich ursprünglich in einem hohen Winkel zur Subduktionszone gebildet haben.Olivine, Pyroxene und Plagioklase haben primitive Zusammensetzungen. Auf Alreiche Hochdruck-Amphibole folgen Al-arme Tiefdruck-Hornblenden. Ein Modell, das zwei Stadien der Pluton-Kristallisation und Platznahme vorsieht, wird vorgeschlagen: Ursprüngliche Kristallisation und Segregation im Moho-Niveau zwischen dem intraozeanischen Inselbogen (ungefähr 22–25 km Tiefe) und schließliche Platznahme gefolgt von teilweise Recycling primärer ultramafischer Kumulate und Verfestigung in oberen Krustenniveaus (ungefähr 8–10 km Tiefe). Die Platznahme der Bogen-Plutone war von Epidot-Amphibolit-Fazies Kontaktmetamorphose der intrudierten Vulkanite und Pyroklastite begleitet.Haupt- und Spurenelement-Analysen der plutonischen Gesteine weisen auf kalkalkalischen Charakter und eine Platznahme in einem primitiven Insenbogensetting hin. Die tektonische Situation, das Alter und die Strukturen der Platznahme lassen erkennen, daß these Plutone den Wechsel in geodynamischen Bedingungen von Inselbogenbezogener Kompression zu lokaler Extension repräsentieren, Vorgänge die mit den initialen Stadien der Öffnung des proto-Komandorsky Beckens zusammenhängen. Auf der Basis der Plutone des nordöstlichen Kamchatka wird ein Modell des Krustenwachstums in magmatischen Bögen vorgeschlagen, das auf zwei Stadien beruht. Während des ersten Stadiums werden primitive basaltische Schmelzen längs der Kruste-MantelGrenze unter dem Bogen intrudiert. Andauernde Fraktionicrung und Akkumulation Olivin-reicher Kumulatgesteine an der Basis der wachsenden Inselbogenkruste resultiert dann in der Produktion einer entwickelten Schmelze die spdter in der Kruste des oberen Bogens Platz genommen hat. Kristallfraktionierung eines seichten magmatischen Reservoirs des zweiten Stadiums unter den aktiven Vulkanen des Bogens führte dann zur Bildung signifikanter Mengen plutonischer Gesteine und zur Eruption von mafischen bis intermediären kalk-alkalischen Laven an der Oberfläche.

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Holocene climate and environmental changes inferred from sediment characteristics and diatom assemblages in a core from Hwajinpo Lagoon,Korea     

Ara Cho  Daekyo Cheong  Jin Cheul Kim  Dong-Yoon Yang  Jin-Young Lee  Kaoru Kashima  Kota Katsuki 《Journal of Paleolimnology》2018,60(4):553-570

Hwajinpo is the largest lagoon in Korea and is located along the east coast of the country. It possesses Holocene sediments that provide an important record of past climate change. We studied the evolution of Hwajinpo Lagoon using grain size data and diatom assemblages in an 11.0-m core (HJ02), which was obtained at the mouth of a small river that drains into the lagoon. Core chronology was established with accelerator mass spectrometry ¹⁴C dates and optically stimulated luminescence dates. Diatom assemblages and grain size analysis revealed that estuarine conditions in the inner lagoon area transitioned to an open embayment ca. 8 ka as a result of sea-level rise. Around 7.8 ka, the open bay became a semi-closed bay as a consequence of development of a sand barrier. After the bay was semi-closed, marine water inflow was increasingly restricted as the sand barrier developed, and the semi-closed bay became a completely enclosed, low-salinity, brackish lagoon around 6 ka. There was an erosional hiatus between 5.5 and 1.7 ka (7.0 m depth), likely caused by river flooding and a switch in the location of drainage along the delta. The lagoon became oligohaline around 1.6 ka, likely because of increasing precipitation associated with an intensified Asian summer monsoon. This increase in precipitation resulted in expansion of the sand bar by sediment inflow, driven by agricultural development in the area. About 1000 years ago, the diatom assemblage was similar to the modern assemblage, suggesting the lagoon’s current geomorphic conditions had been established.  相似文献   

Changes of precipitation amounts and extremes over Japan between 1901 and 2012 and their connection to climate indices   总被引：5，自引：0，他引：5  

Weili Duan  Bin He  Kaoru Takara  Pingping Luo  Maochuan Hu  Nor Eliza Alias  Daniel Nover 《Climate Dynamics》2015,45(7-8):2273-2292

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Evaluation of the JNLT site     

Hiroyasu Ando  Takeshi Noguchi  Masao Nakagiri  Akihiko Miyashita  Yasumasa Yamashita  Kyoji Nariai  Hiroyoshi Tanabe 《Astrophysics and Space Science》1989,160(1-2):183-189

Two steps have been taken to decide at what place and altitude to set up the JNLT on Mauna Kea. First, the wind tunnel experiment has been made in collaboration with the Institute of Meteorology using the two models of summit area with the reduced scales of 1/1000 and 1/5000. This study tells us that the north-west cone is suitable for JNLT. Secondly, we have done the measurement of the microthermal activities in this area with a 30 m tower, which was continued for about 4 months in collaboration with the University of Hawaii. This experiment has given the mean vertical profile ofC _T ² over 4 months and its scale height in the boundayr layer on our site. By use of these measurements, the contribution of the boundary layer to seeing is estimated. The behaviour ofC _T ² under strong winds can be explained very well by topographic effects, which is in fairly good agreement with the results of our wind tunnel experiment.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 2, 1988.  相似文献   

Direct measurement of the swimming speed, tailbeat, and body angle of Japanese flounder (Paralichthys olivaceus)     

Kawabe  Ryo; Naito  Yasuhiko; Sato  Katsufumi; Miyashita  Kazushi; Yamashita  Nariharu 《ICES Journal of Marine Science》2004,61(7):1080-1087

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Comparison of surface velocities determined from altimeter and drifting buoy data     

Kaoru Ichikawa  Shiro Imawaki  Haruo Ishii 《Journal of Oceanography》1995,51(6):729-740

Surface velocities determined from trajectory of a drifting buoy from March through November 1987 are compared with surface geostrophic velocities determined from sea surface dynamic topography (SSDT) obtained from altimetry data with the aid of long-term hydrographic observation data. In general, these velocities show similar temporal variations in both zonal and meridional components, except in a period when obvious error is found in the altimetric SSDT field. When the buoy was trapped by several mid-ocean meso-scale eddies, the comparison is especially good. Systematic discrepancy is found, however, when the buoy was in the Kuroshio region, because of using both temporally and spatially smoothed mean SSDT estimated from hydrographic data; instead, surface geostrophic velocities determined from the altimetric SSDT referred to the improved geoid model result in better comparison.  相似文献   

Monitoring Surface Velocity from Repeated ADCP Observations and Satellite Altimetry   总被引：1，自引：1，他引：1  

Kaoru Ichikawa  Noriaki Gohda  Masazumi Arai  Arata Kaneko 《Journal of Oceanography》2004,60(2):365-374

A method has been developed to monitor the surface velocity field by combining repeated acoustic Doppler current profiler (ADCP) observations and satellite altimetry data. The geostrophic velocity anomaly is calculated from the sea surface height anomaly field estimated from the altimetry data by an optimal interpolation. It has been confirmed that this accurately observes the smoothed velocity anomaly field when the interpolation scales are set according to the spatio-temporal sampling pattern of the altimeter used. The velocity anomaly obtained from the altimetry data is subtracted from the repeated ADCP observations to estimate temporal mean velocity along the ship tracks. Regularly sampled, nine-year time series of surface velocity can then be obtained by adding the computed mean velocity and the altimetry anomaly components. This clearly illustrates surface velocity fluctuations such as the movement of the Kuroshio axis due to its meandering and an increase of the interannual variability of the Subtropical Countercurrent toward its downstream region. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Concentrations of 222 Rn, Its Short-Lived Daughters And 212 Pb And Their Ratios Under Complex Atmospheric Conditions And Topography     

Toshio Kataoka  Eiji Yunoki  Mitsuo Shimizu  Tadashige Mori  Osamu Tsukamoto  Satoshi Takahashi  Hironori Fudeyasu  Yukitaka Ohashi  Ken Sahashi  Toshihiko Maitani  Koh'ichi Miyashita  Toru Iwata  Takayuki Sasaki  Yoko Fujikawa  Akira Kudo  Roger H. Shaw 《Boundary-Layer Meteorology》2003,107(1):219-249

Atmospheric activity concentrations of ²¹²Pb and short-lived ²²²Rndaughters, together with meteorological elements, have been observed continuously atthree sites at Kamisaibara Village in Japan. In addition, atmospheric activity concentrationof ²²²Rn, equilibrium-equivalent concentration of ²²²Rn and conditionsof the lower atmosphere were observed for three intensive observation periods at Akawase,one of the three sites in Kamisaibara Village. The equilibrium-equivalent concentration of²²²Rn is almost the same as the atmospheric activity concentration of short-lived²²²Rn daughters.The activity concentrations of ²¹²Pb and the short-lived ²²²Rn daughtersand their ratio were low in the daytime owing to convective mixing, and high at nightowing to the surface-based inversion during periods of no precipitation. Their variationshave several patterns corresponding to the scale of the drainage wind or weak mixing.Mechanical mixing due to strong winds through both day and night during the first andsecond observation periods made the atmospheric activity concentrations of ²¹²Pb and the short-lived ²²²Rn daughters continuously low. However, their ratios werecontinuously high during the first period yet continuously low during the second period.This difference can be explained by the effect ofextraction of ²²⁰Rn and ²²²Rndue to strong winds and snow cover. There were also cases in which the ratio of theatmospheric activity concentration of ²¹²Pb to that of the short-lived ²²²Rndaughters at night was equal to or less than the ratio in the daytime. Thisinverse trend, asin the periods of no precipitation mentioned above, is considered to be due to near-neutralconditions on these nights.We find a difference in the ratio of the equilibrium-equivalent concentration of²²²Rn (the activity concentration of short-lived ²²²Rn daughters) tothe activity concentration of ²²²Rn during the first observation period and thatduring the second. The difference can be explained by snow cover on the ground. Wealso find differences among the ratios of the activity concentration of the short-lived²²²Rn daughters to that of ²²²Rn during the three observation periods.These differences can be explained by the submergence of paddy fields.  相似文献   

The economic effects of harmful algal blooms in the United States: Estimates,assessment issues,and information needs     

P.?HoaglandEmail author  D.?M.?Anderson  Y.?Kaoru  A.?W.?White 《Estuaries and Coasts》2002,25(4):819-837

During the last several decades, harmful algal bloom (HAB) events have been observed in more locations than ever before throughout the United States. Scientists have identified a larger number of algal species involved in HABs, more toxins have been uncovered, and more fisheries resources have been affected. Whether this apparent increase in HAB events is a real phenomenon or is the result of increased sampling and monitoring is a topic of intense discussions within the scientific community. We also have an inchoate understanding of the reasons for the apparent increase, particularly concerning the role of anthropogenic nutrient loadings as a causal factor. Whatever the reasons, virtually all coastal regions of the U.S. are now regarded as potentially subject to a wide variety and increased frequency of HABs. It is important to begin to understand the scale of the economic costs to society of such natural hazards. It is a common, but not yet widespread, practice for resource managers and scientists in many localities to develop rough estimates of the economic effects of HAB events in terms of lost sales in the relevant product or factor markets, expenditures for medical treatments, environmental monitoring and management budgets, or other types of costs. These estimates may be invoked in policy debates, often without concern about how they were developed. Although such estimates are not necessarily good measures of the true costs of HABs to society, they may help to measure the scale of losses and be suggestive of their distribution across political jurisdictions or industry sectors. With adequate interpretation, our thinking about appropriate policy responses may be guided by these estimates. Here we compile disparate estimates of the economic effects of HABs for events in the U.S. where such effects were measured during 1987–1992. We consider effects of four basic types: public health, commercial fisheries, recreation and tourism, and monitoring and management. We discuss many of the issues surrounding the nature of these estimates, their relevance as measures of the social costs of natural hazards, and their potential for comparability and aggregation into a national estimate.  相似文献