Testing of a towed CTD     

Yukio Fujinawa  Yoshinobu Tsuji  Isao Watabe  Ken Sasaki  Masao Nomoto  Toshiaki Hara  Yoshito Tsuji 《Journal of Oceanography》1980,36(5):253-258

The results of laboratory and field experiments on a CTD measuring unit attached to a controllable towed body is described. It was verified that the three-dimensional distribution of salinity and temperature could be observed with sufficient accuracy (to 0.03 in salinity and to 0.01°C in temperature if proper correction is adopted) while cruising at up to 4 knots. A double integrated A/D converter is used to compensate for effects of extraneous environmental changes.  相似文献   

Interannual variability of the Kuroshio transport passing through the 137°E meridian in an OGCM related to the North Pacific windstress     

Yoshinobu Wakata  Takashi Setou  Ikuo Kaneko  Hiroshi Uchida  Shiro Imawaki 《Journal of Oceanography》2006,62(1):25-35

The interannual variability of the Kuroshio volume transport passing through the 137°E meridian south of Japan was simulated with an ocean general circulation model (OGCM). The time series of the Kuroshio volume transport over the 1000 m depth in the OGCM is well reproduced by the one-dimensional quasi-geostrophic (QG) vorticity equation with a windstress forcing. In our analysis of the OGCM and QG results, we found that peaks and troughs of the time series of the Kuroshio volume transport with 2–3 yr time-scale were induced by windstress curl, both local and immediately eastward, whereas longer time-scale variability was also induced by windstress curl near the dateline.  相似文献   

Stokes' expansion of internal deep water waves to the fifth order     

Yoshinobu Tsuji  Yutaka Nagata 《Journal of Oceanography》1973,29(2):61-69

Stokes' expansion is applied to the internal waves of finite amplitude, which propagate on the interface between two layers of infinite thickness. Stream function, wave profile, phase velocity and mass transport velocity are given in the fifth order approximation. It is shown that (a) phase velocity increases with increase of wave steepness, (b) mass transport appears in the direction of the wave propagation in both layers as in the case of the surface waves, and (c) when the density difference is very small, the wave profile is flattened not only at the troughs but also at the crests.  相似文献   

Influence of Source/Sink Distributions on Flux–Gradient Relationships in the Roughness Sublayer Over an Open Forest Canopy Under Unstable Conditions     

Hiroki Iwata  Yoshinobu Harazono  Masahito Ueyama 《Boundary-Layer Meteorology》2010,136(3):391-405

The flux–gradient relationships in the unstable roughness sublayer (RSL) over an open canopy of black spruce forest were examined using long-term observations from an instrumented tower. The observed gradients normalised with the surface fluxes and height above the zero-plane displacement showed differences from a universal function established in the surface layer. The magnitude of differences was not constant throughout the year even at the same observation height. Also the magnitude of the differences was different for each scalar, and scalar similarity in the context of the flux–gradient relationship did not always hold. The variation of the differences was explained by the relative contribution of overstorey vegetation to the total flux from the entire ecosystem. This suggests that a mismatch of the vertical source/sink distributions between scalars leads to a different strength of the near-field dispersion effect for each scalar, and this resulted in inequality of eddy diffusivity among scalars in the RSL. An empirical method that predicts the magnitude of differences is proposed. With this method, it is possible to estimate the eddy diffusivity of scalars provided that the relative contribution of overstorey vegetation to the total flux from the ecosystem is known. Also this method can be used to estimate the eddy diffusivity for scalars whose primary sources are at ground level, such as methane and nitrous oxide.  相似文献   

Petrochemistry of Late Miocene to Quaternary Igneous Rocks and Metallogenesis in Southwest Hokkaido, Japan     

Eijun OHTA  Yoshinobu KAWANO  Mitsuru NAKAGAWA  Hiroo KAGAMI 《Resource Geology》1998,48(3):183-195

Abstract: Southwest Hokkaido is largely covered by Late Miocene to Quaternary igneous rocks, and has a large number of gold veins and base-metal veins of the same age. Investigation of the silica-normalized concentration of elements has revealed regional petrochemical zoning; large ion lithophile elements (LILE) and K₂O/(Na₂O+K₂O) of the rocks increase toward Japan Sea, whereas total FeO, CaO, and ⁸⁷Sr/⁸⁶Sr decrease. Mapped concentration isoplethes of these elements are not ideally parallel to the volcanic front, but protrude to the west at Funka Bay, and to the northwest at Matsumae Peninsula. Isoplethes of ⁸⁷Sr/⁸⁶Sr show similar patterns and two more northwestward protrusions in the northeast (Jozankei block) of southwest Hokkaido. Contrary to the general petrochemical trend, both high– and low-LILE volcanic rocks occur in the Jozankei block. The ore deposits are distributed in four metallogenic zones; manganese–base–metal zone on the Japan Sea side, pyrite-limonite zone mainly along the volcanic front, gold zone in the middle, and two units of gold–base–metal zone. The northern unit of this zone is in the Jozankei block, and seems a part of the gold zone overlapped by the manganese–base–metal zone. Thus, as a rule, pyrite–limonite, gold, and base-metal deposits accompany low–, intermediate–, and high-LILE igneous rocks, respectively. Individual deposits and volcanic rocks make chains oblique to the zones and the volcanic front. The majority of the ore deposits are distributed along ridges of Bouguer anomalies overlapped by the volcanic chains, which apparently control the patterns of the petrochemical isoplethes. This is typical for two volcanic chains to the north and south of Funka Bay, where the petrochemical isoplethes protrude to the west. This indicates that both the igneous activity and the mineralization have been under the control of tectonic fractures at the roots of the volcanic chains. The geological, petrochemical and metallogenic data support the idea that the chemical characteristics of the deposits are correlated mainly with the chemistry of the associated magmas, and partly with that of the host rocks.  相似文献   

Na i D brightening phenomena in quiescent prominences     

Yoshinobu Nikaidou 《Solar physics》1982,80(2):259-277

The Na i D emission lines are found to brighten temporarily in restricted regions of quiescent prominences and we call the phenomena the Na i D brightenings. The comparison of observed intensities of Na i D lines with model calculations shows that the phenomena is attributed to a kind of local activation of quiescent prominences accompanied by mass motions. The Na i D lines are emitted from extraordinarily high pressure regions in which the pressure rises up to 0.37 2.7 dyn cm^–2 and the temperature seems to be in the range between 5800 7000 K. The line-of-sight velocity of the mass motions amounted to several tens of km s^–1 in some Na i D emitting prominences investigated. The life time of the phenomena is estimated to be about several tens of minutes.  相似文献   

全球重要农业文化遗产静冈传统茶草综合系统:价值、保护与行动（英文）     

Hidehiro INAGAKI  Yoshinobu KUSUMOTO 《资源与生态学报(英文版)》2019,(5)

日本静冈的传统茶草综合系统是当地政府申请的日本第一个全球重要农业遗产系统(GIAHS)。本文介绍了当初发现该系统的背景、为申报GIAHS所采取的措施以及被列入全球重要农业文化遗产名录后,静冈茶草系统当前的作用和面临的新情况。自2013年入选全球重要农业遗产系统,目前日本的半天然草原大幅减少,但在静冈的茶草系统里发现了独特的半天然草原,茶园里生物多样性非常丰富。这些茶草系统和采用的传统耕作方法被称为"Chagusaba"。然而,GIAHS的申请过程并不容易,因为许多当地农民不了解他们传统耕作方法和GIAHS品牌的价值。在Chagusaba入选GIAHS名单之后,我们的主要工作是相关的品牌推广,努力使传统农业生产出高品质的茶叶。随着日本农业节省劳动力技术的进步,劳动力成本降低,优质茶叶的价格也有所下降,因此,执行低效传统耕作方式的农民数量越来越少。有必要正确地重新认识传统农业方法种植的茶叶的价值,并在价格上得以体现。静冈县当地政府目前正致力于实施认证体系,包括利用GPS进行科学评估,以及引入生物多样性指标等等。  相似文献   

Seasonal variability of the sea surface height in the East China Sea along the China coast: A model study     

Yoshinobu Wakata 《Journal of Oceanography》2009,65(2):281-286

The phase of the sea surface height annual variation in the East China Sea along China’s continental coast is delayed from that in the open ocean area, most probably because of seasonal strong monsoon winds. To elucidate this mechanism, we conducted an idealized model experiment using a rectangular shallow ocean with a sloped seafloor forced by southward blowing winds. We obtain a locally confined high SSH near the western boundary found in the East China Sea. The delay of the phase of the sea surface height (SSH) along the China coast can be interpreted as follows. The SSH of the East China Sea is high over large areas in September and low in March due to the expansion/contraction of seawater, which is attributable to the sea surface heat flux. However, near the continental boundary SSH becomes high in January and low in July under the influence of a monsoon winds. The phase delay along the continental boundary should appear by superposing these two time series with a phase difference near the boundary.  相似文献   

Geological and Hydrodynamical Examination of the Bathyal Tsunamigenic Origin of Miocene Conglomerates in Chita Peninsula, Central Japan     

Toru Tachibana  Yoshinobu Tsuji 《Pure and Applied Geophysics》2011,168(6-7):997-1014

A conglomerate appears on a rocky coast called ??Tsubutega-ura Coast??, located on the southwestern coast near the southern tip of the Chita Peninsula, Aichi Prefecture, central Japan. The conglomerate belongs to Miocene sedimentary rocks termed the Morozaki Group. The conglomerate includes meter-scale boulders, indicating that it was formed by an extraordinary event. In the geological investigation, we observed that the conglomerate shows alternate changes of paleocurrent directions between seaward and landward. This feature is supposed to be formed by tsunami currents. In the hydrodynamical investigation, we obtained following results: (1) the lowest limit of a current velocity to move a boulder of about 3?m in diameter would be about 2?C3?m/s, (2) the speed of tsunami currents reproduced by tsunami simulation exceeds 3?m/s at 300?m in depth when the tsunami is generated by a gigantic earthquake with magnitude 9.0 or more, (3) the transport distance of the boulder would be several hundred?meters to several kilometers by one tsunami event caused by a gigantic earthquake. We conclude that tsunamis best explain the formation of the conglomerate deposited in upper bathyal environments about 200?C400?m depth, both from geological and hydrodynamical viewpoints.  相似文献   

Variations in fraction of absorbed photosynthetically active radiation and comparisons with MODIS data in burned black spruce forests of interior Alaska     

Hiroki Iwata  Masahito Ueyama  Chie Iwama  Yoshinobu Harazono 《Polar Science》2013,7(2):113-124

Absorption of photosynthetically active radiation (PAR) by vegetation was observed in two burned black spruce forests, one and seven years after wildfire, in interior Alaska along with several vegetation properties. This study considered PAR absorption by mosses by examining the relationship between PAR transmittance and fractional coverage of green vegetation. Our results suggest that mosses absorbed a considerable fraction of incoming PAR in the burned forests, which cannot be neglected in evaluating the fraction of absorbed PAR (FPAR). The relationships between FPAR and vegetation indices revealed that enhanced vegetation index (EVI) may be suitable for expressing the spatial and temporal variation of FPAR, regardless of stand age after wildfire. The comparison between the observed in situ FPAR and FPAR derived from Moderate Resolution Imaging Spectroradiometer (MODIS FPAR) clearly showed that MODIS FPAR was highly overestimated. The most likely reason for the overestimation was identified as misclassification of land cover type. The current regional estimation of photosynthesis in boreal region based on the light-use efficiency approach and MODIS FPAR is probably overestimated, and an accurate distribution of FPAR is desired for clarifying the regional carbon exchange in boreal forests.  相似文献