Four-dimensional variational ocean reanalysis: a 30-year high-resolution dataset in the western North Pacific (FORA-WNP30)     

Norihisa Usui  Tsuyoshi Wakamatsu  Yusuke Tanaka  Nariaki Hirose  Takahiro Toyoda  Shiro Nishikawa  Yosuke Fujii  Yasushi Takatsuki  Hiromichi Igarashi  Haruka Nishikawa  Yoichi Ishikawa  Tsurane Kuragano  Masafumi Kamachi 《Journal of Oceanography》2017,73(2):205-233

We produced a four-dimensional variational ocean re-analysis for the Western North Pacific over 30 years (FORA-WNP30). It is the first-ever dataset covering the western North Pacific over 3 decades at eddy-resolving resolution. The four-dimensional variational analysis scheme version of the Meteorological Research Institute Multivariate Ocean Variational Estimation system (MOVE-4DVAR) is employed to conduct a long-term reanalysis experiment during 1982–2012. After evaluating the basic performance of FORA-WNP30, the interannual to decadal variability is analyzed. Overall, FORA-WNP30 reproduces basic features in the western North Pacific well. One of outstanding features in FORA-WNP30 is that anomalous events such as the Kuroshio large meander and anomalous intrusion of the Oyashio in the 1980s, when there were no altimeter data, are successfully reproduced. FORA-WNP30 is therefore a valuable dataset for a variety of oceanographic research topics and potentially for related fields such as climate study, meteorology and fisheries.  相似文献   

Evaporation from the desert: Some preliminary results of HEIFE   总被引：1，自引：0，他引：1  

Jieming Wang  Yasushi Mitsuta 《Boundary-Layer Meteorology》1992,59(4):413-418

As part of a feasibility study for HEIFE, a Sino-Japanese Cooperative Research Program on Atmosphere-Land Surface Processes in Heihe River Basin, fluxes of water vapour are estimated above and below the sand surface. It is found that during the daytime under clear skies, the water vapour flux is directed towards the surface from both the atmosphere above and the sand below.  相似文献   

Partitioning of heavy metals into mineral and organic fractions in a sediment core from Tokyo Bay     

Yasushi Kitano  Masahiro Sakata  Eiji Matsumoto 《Geochimica et cosmochimica acta》1980,44(9):1279-1285

Sediment core was collected from Tokyo Bay. The surface enrichment of heavy metals due to human activities is recognized in the sediment. Partitioning of Cu, Zn, Fe and Mn into sulfide, carbonate, organic and silicate fractions has been determined with selective chemical leaching techniques for ²¹⁰Pb-dated sediment core samples. The heavy metal contents of silicate fractions without exchangeable sites are almost constant against depth in sediment core. However, the Cu, Zn and Mn contents of sulfide, carbonate and organic fractions vary with depth. Most Cu and Zn in the polluted sediment layer are associated with the iron sulfide fraction.  相似文献   

Late Cenozoic Metallogeny of Southwest Hokkaido, Japan     

Yasushi WATANABE 《Resource Geology》2002,52(3):191-210

Abstract: This paper reviews the Miocene to Pleistocene tectonic framework, geology, magmatic style and stress field of southwest Hokkaido, Japan, and compiles deposit form, type, ore and alteration minerals, strike and length of mineralized veins, and associated igneous activity. The late Cenozoic tectonic regime of the Sapporo‐Iwanai ore district is divided into five periods on the basis of the subduction mode of the Pacific plate: Period 1 (15.0–12.1 Ma) oblique‐subduction setting with an orthogonal convergence rate (OCR) of 51–81 mm/y; Period 2 (12.1–6.2 Ma) normal subduction with an OCR of 81–94 mm/y; Period 3 (6.2–3.6 Ma) oblique subduction setting with an OCR of 73–99 mm/y; Period 4 (3.6–1.5 Ma) normal‐subduction setting with an OCR of 99–103 mm/y and Period 5 (1.5–0 Ma) oblique‐subduction setting with an OCR from 99 to 57 mm/y. The hydrothermal deposits in the district include Kuroko deposits of Period 1 and epithermal vein‐type deposits of Periods 2 to 5. The Kuroko deposits were accompanied by submarine monogenetic rhyolite volcanism associated with tholeiitic basalt in the backarc region. In contrast, Late Miocene to Pliocene epithermal vein‐type deposits were associated mainly with polygenetic andesite and monogenetic rhyodacite volcanism of calc‐alkaline series. These different styles of magmatism occurred in an extensional tectonic regime (Period 1), and weakened extensional (Periods 2–3) or neutral tectonic regimes (Periods 4). Periods 2–5 epithermal vein‐type deposits are divided into base‐metal and precious‐metal deposits. The base‐metal deposits are associated mainly with large (>5 km in diameter) polygenetic andesitic volcanoes and subvol‐canic intrusions. The precious‐metal deposits are associated with small (<5 km in diameter) polygenetic or monogenetic volcanoes and/or subvolcanic intrusions of andesite, dacite and rhyolite near the volcanic arc front. This difference in distribution is ascribed to different states of horizontal differential stress. Productive vein‐type deposits, such as Toyoha, Inakuraishi, Ohe and Chitose, formed in the neutral regime with a large horizontal differential stress during Period 4, which may have promoted strike‐slip faulting and non–extrusive, subvol‐canic intrusion. This tectonic regime and stress field resulted from the normal subduction of the Pacific plate with elevated velocity. This observation leads to the conclusion that large metallic deposits in southwest Hokkaido are expected to have formed primarily during Pliocene magmatic‐hydrothermal activity, when the orthogonal convergence rate was highest and strike‐slip faulting was active.  相似文献   

The turbulent structure of the internal boundary layer near the shore     

Toshimasa Ohara  Yasushi Ogawa 《Boundary-Layer Meteorology》1985,32(1):39-56

The mean structure within the internal boundary layer (IBL) near the shore, which develop from the coast in the presence of a sea breeze, has been described in Part I of this study (Ogawa and Ohara, 1984). This paper presents the results of the similarity and energy budget analysis for the purpose of parameterization of the turbulent structure within the IBL. The analysis of the turbulent kinetic energy balance, turbulent intensities and spectra show that the wind is strongly affected by mechanical turbulence in comparison with the past results in a fully developed convective layer where thermal convection dominated. The standard deviations of the wind velocities normalized by the friction velocity u _* (surface-layer scaling parameter) are functions only of the normalized height z/Z _i within 160 m of the shoreline, where Z _i is the IBL. On the other hand, the standard deviations of temperature normalized by _* (mixing-layer scaling parameter) have less scatter with distance than those normalized by T _* (surface-layer scaling parameter). The data showed that both u _* (not a mixed-layer parameter), and Z _i (not a surface-layer parameter) are necessary to describe the turbulent characteristics of the IBL near the shore.Deceased March, 1984.  相似文献   

The turbulent structure of the internal boundary layer near the shore     

Yasushi Ogawa  Toshima Ohara 《Boundary-Layer Meteorology》1985,31(4):369-384

A field experiment to measure the turbulent structure of the internal boundary layer near the shore was conducted using three instrumented meteorological poles, a kytoon, and a crane-mounted ultrasonic anemometer-thermometer, as well as three reference ultrasonic anemometer-thermometers positioned near the poles. Part 1 of this study gives the explicit details and general characteristics for one run of the experiment. Part 2 (Ohara and Ogawa, 1984) will present a similarity and energy budget analysis. The mean velocity profiles showed that there was wind speed acceleration due to the sea-land temperature difference. In addition, the velocity profiles consisted of three distinct regions; the region near the ground had the largest gradient followed by a transition zone which had a small velocity gradient, while above, the profile resembled the oncoming sea breeze. In general, the turbulence was greatest near the shore, gradually decreasing inland. The lowest region had large turbulence intensities and the transition region had some intermittent turbulence characteristics between the lower strong unstable layer and the relatively turbulent-free region above.Deceased March 1984.Present address: The Institute of Behavioral Sciences, Yoyagi, Tokyo 151, Japan.  相似文献   

The effects of mesoscale convective cells on the surface wind field over the ocean     

Hiroshi Ishida  Wayne V. Burt  Yasushi Mitsuta 《Boundary-Layer Meteorology》1984,29(1):75-84

Near-surface wind velocities were measured on an array of anchored spar buoys in the East China Sea in February 1975 as a part of the Japanese AMTEX '75 (Air Mass Transformation Experiment), a subprogram of GARP. These data were used to determine the effects of atmospheric convection associated with mesoscale convective cells (MCC) on near-surface winds over the ocean. When MCC were present, a peak occurred in the near-surface wind spectrum in the so-called spectral gap.  相似文献   

IMA Kobe 2006 Special Issue: Precious and Base-Metal Deposits in Magmatic Arcs     

Yasushi  Watanabe 《Resource Geology》2007,57(4):353-353

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Correction to: A web-based real-time and full-resolution data visualization for Himawari-8 satellite sensed images     

Ken T. Murata  Praphan Pavarangkoon  Atsushi Higuchi  Koichi Toyoshima  Kazunori Yamamoto  Kazuya Muranaga  Yoshiaki Nagaya  Yasushi Izumikawa  Eizen Kimura  Takamichi Mizuhara 《Earth Science Informatics》2018,11(2):239-240

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Observation and estimation of daily actual evapotranspiration and evaporation on a glacierized watershed at the headwater of the Urumqi River,Tianshan, China     

Zhang Wanchang  Zhang Yinsheng  Katsuro Ogawa  Yasushi Yamaguchi 《水文研究》1999,13(11):1589-1601

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