scholarly journals Explosively Developing Cyclone Activity in Relation to Heavy Snowfall on the Japan Sea Side of Central Japan

2012 ◽  
Vol 90 (2) ◽  
pp. 275-295 ◽  
Author(s):  
Yoshitaka YAMASHITA ◽  
Ryuichi KAWAMURA ◽  
Satoshi IIZUKA ◽  
Hiroaki HATSUSHIKA
2008 ◽  
Vol 27 (2) ◽  
pp. 161-175 ◽  
Author(s):  
Hirokazu Ozawa ◽  
Hideaki Nagamori ◽  
Tomotaka Tanabe

Abstract. Pliocene strata (4–3 Ma) in the Togakushi area, central Japan, yield significant ostracods, which allow investigation of the origins of high-latitude (Arctic–Atlantic) taxa and the Japan Sea endemic species, together with their post-Miocene history of extinction-speciation and migration. Three types of extinct species are found here: (1) cryophilic species in common with, or closely related to, species in Plio-Pleistocene assemblages described from the Japan Sea; (2) species closely related to, or comparable with, species that characterize Miocene Japan; and (3) species endemic to the Pliocene Japan Sea. Type (1) contains species closely related to high-latitude species known from the Arctic and northern Atlantic Oceans. Their presence suggests migration from the northwestern Pacific to the northern Atlantic through the Arctic seas since the Late Pliocene after the opening of the Bering Strait. Both Types (2) and (3) contain genera originating in the south, which show high specific diversity in regions affected by the modern warm Kuroshio Current. Ancestral ostracods of Types (2) and (3) invaded the Japan Sea from the Pacific from the Middle Miocene, and diversified to produce closely related species in the semi land-locked Japan Sea until the Early Pliocene. Two new species Aurila togakushiensis sp. nov. and Aurila shigaramiensis sp. nov. are described.


Erdkunde ◽  
2011 ◽  
Vol 65 (3) ◽  
pp. 233-245 ◽  
Author(s):  
Koichi Watanabe ◽  
Hideharu Honoki ◽  
Shinji Iwama ◽  
Kaname Iwatake ◽  
Shunya Mori ◽  
...  

2020 ◽  
Author(s):  
Xuefa Shi ◽  
Jianjun Zou ◽  
Sergey Gorbarenko

<p>The Japan Sea, one of the marginal seas of the North Pacific, communicates with adjacent seas through four shallow straits (<130 m) and the present environment in the Japan Sea is mainly forced by the Tsushima Warm Current (TWC), East Asia Monsoon (EAM) and seasonal sea ice. During the Quaternary, the pronounced effects of glacial eustatic sea level on the hydrography, ocean biogeochemistry and sediment depositions in the Japan Sea over glacial-interglacial cycles. However, the spatial heterogeneity of these forcings exerting on environment of the Japan Sea may results in contrasting response. On the basis of a suite of sediment cores collected during the China-Russia joint expedition in 2010, we investigate the sedimentary processes and paleoenvironment changes in the Japan Sea. We found enhanced extent of seasonal sea-ice coverage in the western Japan Sea, which is synchronous with the intensification of East Asian Winter Monsoon (EAWM) from 15ka to 8ka. During the early last deglaciation (17ka-15ka), perennial sea ice cover at investigated site occurs and thus inhibits the deepwater formation in the Japan Sea. Since 8 ka, increased deep ventilation and dampened sea ice coverage are closely related to enhanced EAWM and invasion of high-salinity TWC into the Japan Sea. In the southern Japan Sea, the sediment provenance is mainly derived from the Yangtze and old yellow rivers, while the terrigenous matter was mainly sourced from the Yangtze River after 7 ka, on the basis of elemental and radiogenic isotopic data (Sr and Nd) of fine-sized (<63 μm) sediments. Abrupt shifts in sediment provenance occurred at ~18 ka and ~7 ka and these time periods are synchronous with changes in surface hydrography and deep ventilation in the Ulleung Basin. In the central Japan Sea, eolian dust sourced from central Asia and Chinese Loess Plateau by westerly was delivered to the central Japan Sea. In addition, deep ventilation in the southern and central Japan Sea evidenced by redox-sensitive elements and ventilation-like radiolarian species suggest intensified ventilation since 8ka and during cold spells of the last deglaciation, which is closely related to the invasion of the Tsushima Warm Current into the Japan Sea. Our data suggest that sea level is a first-order factor in controlling the environment and sediment deposition in the Japan Sea at orbital timescales, while the East Asian Monsoon and Kuroshio Current play a secondary role. Note: This study was supported by the National Natural Science Foundation of China (Grants No. 41420104005, U1606401) and National Program on Global Change and Air-Sea Interaction (GASI-GEOGE-03 &-04).<span> </span></p>


2011 ◽  
Vol 52 (58) ◽  
pp. 102-110 ◽  
Author(s):  
Koichi Watanabe ◽  
Yukiko Saito ◽  
Syoko Tamura ◽  
Yuki Sakai ◽  
Nagisa Eda ◽  
...  

AbstarctMeasurements of the chemical composition of the snow pits at Murododaira (2450m a.s.l.), Mount Tateyama, near the coast of the Japan Sea in central Japan, were performed each spring from 2005 through 2008. The mean concentrations of nssSO42– and NO3– are higher than those in snowpack in the 1990s. The pH and nssCa2+ were usually high in the upper parts of 2–3m of snow deposited in the spring, when Asian dust (Kosa) particles are frequently transported. High concentrations of nssSO42– were detected in both the spring and winter layers. The high-nssCa2+ layers usually contained high concentrations of nssSO42–. The results show that not only Kosa particles but also air pollutants might have been transported long-range from the continent of Asia. The concentrations of peroxides were high in the new snow (precipitation particles) and granular snow (coarse grain, melt forms) layers. The peroxide concentrations in the snow layers were negatively correlated with the nssCa2+ concentrations. High peroxide concentrations may be preserved in granular snow layers having low concentrations of nssCa2+.


2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Hiroyuki Shimizu ◽  
Ryuichi Kawamura ◽  
Tetsuya Kawano ◽  
Satoshi Iizuka

The dynamical impact of the Changbai Mountain Range in the Korean Peninsula on the extratropical cyclone activity over the Japan Sea in early winter is examined using the Weather Research Forecasting model. We have conducted two independent long-term integrations over 15 winter months (December only) from 2000 to 2014 with and without modified topography. The results show that the Changbai Mountain Range plays a vital role in increasing cyclone track frequency, low-level poleward eddy heat flux, and the local deepening rate over the Japan Sea through enhancement of the lower-tropospheric baroclinic zone (LTBZ). This mountain range gives rise to activation of the synoptic-scale cyclone activity over that region. From our case study on three typical cyclones, it is found that mesoscale structures in the vicinity of a cyclone’s center are dynamically modulated when it passes through the LTBZ and that cyclogenesis is triggered around that zone. A vorticity budget analysis shows that the stretching term relevant to enhanced low-level convergence plays a dominant role in intensifying cyclonic vorticities. We confirmed that the composite features of the three typical cases are consistent with the statistical ones of the dynamical modulation of the Changbai Mountain on synoptic-scale cyclone activity.


2003 ◽  
Vol 22 (2) ◽  
pp. 169-181 ◽  
Author(s):  
Katsura Yamada

Abstract. The ostracod genus Robertsonites is widely distributed in high-latitude seas of the Northern Hemisphere. It also occurs abundantly in Plio-Pleistocene strata along the coast of the Sea of Japan, which were deposited under the influence of the Japan Sea Proper Water mass, below 150 m. The assemblages of the genus Robertsonites in the seas around Japan are quite different from those in the high-latitude seas of the Northern Hemisphere. A difference in the valve outlines of the genus in the two areas is also apparent. Nine species of the genus Robertsonites are restricted to strata and marine deposits around Japan, although only 12 species have been described world-wide, including the three new taxa described here. The Upper Pliocene Sasaoka and Kuwae formations in northeast and central Japan, contain seven species, including three new taxa, Robertsonites irizukii sp. nov., Robertsonites leptoreticulata sp. nov., and Robertsonites tabukii sp. nov., and one open-nomenclature taxon.


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