Formation, Thermodynamic Structure, and Airflow of a Japan Sea Polar-Airmass Convergence Zone

2021 ◽  
Keyword(s):  
Temperature Gradient ◽  
Satellite Imagery ◽  
Japan Sea ◽  
Forecast Model ◽  
The Sea Of Japan ◽  
Convergence Zone ◽  
Horizontal Scale ◽  
Thermodynamic Structure ◽  
The Japan Sea ◽  
Flow Splitting

Abstract The Sea of Japan (SOJ) coast and adjoining orography of central Honshu, Japan receive substantial snowfall each winter. A frequent contributor during cold-air outbreaks (CAOs) is the Japan Sea Polar-Airmass Convergence Zone (JPCZ), which forms downstream of the Korean Highlands, extends southeastward to Honshu, and generates a mesoscale band of precipitation. Mesoscale polar vortices (MPVs) ranging in horizontal scale from tens (i.e., meso-β-scale cyclones) to several hundred kilometers (i.e., “polar lows”) are also common during CAOs and often interact with the JPCZ. Here we use satellite imagery and Weather Research and Forecast model (WRF) simulations to examine the formation, thermodynamic structure, and airflow of a JPCZ that formed in the wake of an MPV during a CAO from 2–7 February 2018. The MPV and its associated warm seclusion and bent-back front developed in a locally warm, convergent, and convective environment over the SOJ near the base of the Korean Peninsula. The nascent JPCZ was structurally continuous with the bent-back front and lengthened as the MPV migrated southeastward. Trajectories illustrate how flow splitting around the Korean Highlands, channeling through low passes and valleys along the Asian coast, and air-sea interactions affect the formation and thermodynamic structure of the JPCZ. Contrasts in airmass origin and thermodynamic modification over the SOJ affect the cross-JPCZ temperature gradient, which reverses in sign along the JPCZ from the Asian coast to Honshu. These results provide new insights into the thermodynamic structure of the JPCZ, which is an important contributor to hazardous weather over Japan.

scholarly journals Composite Analysis of Polar Mesocyclones over the Western Part of the Sea of Japan

2018 ◽  
Vol 146 (4) ◽  
pp. 985-1004 ◽  
Author(s):  
Shun-ichi I. Watanabe ◽  
Hiroshi Niino ◽  
Wataru Yanase
Keyword(s):  
Sea Of Japan ◽  
Japan Sea ◽  
The Sea Of Japan ◽  
Convergence Zone ◽  
Composite Analysis ◽  
Cold Air ◽  
Cold Air Outbreak ◽  
Pressure Anomaly ◽  
Upper Level ◽  
Inversion Analysis

Polar mesocyclones occur frequently over the Sea of Japan during winter in association with cold air outbreaks from the Eurasian continent. In this study, the general characteristics of polar mesocyclones over the western part of the Sea of Japan are examined using composite analysis. The synoptic-scale environment associated with these mesocyclones is characterized by a negative sea level pressure anomaly to the east that causes a cold air outbreak at low levels. There is also a geopotential height trough moving eastward at upper levels. In the cold air outbreak, a convergence zone known as the Japan Sea polar airmass convergence zone (JPCZ), collocated with a thermal ridge, develops on the lee side of the mountains at the root of the Korean Peninsula. These polar mesocyclones are generated when the upper-level trough approaches the JPCZ from the west. However, the behavior of the JPCZ and the movement of the polar mesocyclones differ depending on the location of the upper-level trough. A piecewise potential vorticity inversion analysis revealed that the circulation associated with the upper-level trough modifies the low-level winds, which affects the direction of extension of the JPCZ as well as the genesis location and the movement of the polar mesocyclones.

scholarly journals AGE RELATIONSHIPS OF RIFTING, SUBDUCTION AND PLUME PROCESSES ON THE EASTERN MARGIN OF ASIA

2021 ◽  
pp. 22-45
Author(s):  
A.M. Petrishchevsky ◽  
◽  
T.A. Emelyanova ◽  
L.A. Izosov ◽  
◽  
...  
Keyword(s):  
Japan Sea ◽  
Time Range ◽  
The Sea Of Japan ◽  
Spatial Distributions ◽  
Southeast China ◽  
Initial Stage ◽  
The Pacific ◽  
The Japan Sea ◽  
Lithospheric Plates ◽  
The Pacific Ocean

Based on the comparison of petrochemical characteristics of volcanics with spatial distributions of rheological heterogeneities in the East Asian tectonosphere, new data on the mechanisms and sequence of subduction, rifting, and plume-type central structures were obtained. Throughout the East Asia transition zone to the Pacific Ocean, subduction began at the initial stage of convergence of lithospheric plates, from 195 Ma in Southeast China to 60 Ma in the Sea of Japan. Subsequent rifting and plume processes have strongly influenced subduction structures. Rifting processes manifested themselves over a wide time range, from 138 Ma to 3 Ma. They can be subdivided into pre-plume and post-plume. Central plume-type structures, accompanied by adakitic volcanism, formed at convergent boundaries of lithospheric segments due to squeezing of the asthenosphere from the mantle by subducting slabs. The age of these structures varies considerably and is 124 Ma in Southeast China, from 37 to 51 Ma in the Okhotsk Sea region, and from 13 to 9 Ma in the Japan Sea region.

scholarly journals New ostracod (Crustacea) species of the genus <i>Robertsonites</i> from the Upper Pliocene Kuwae and Sasaoka formations, central and northeast Japan

2003 ◽  
Vol 22 (2) ◽  
pp. 169-181 ◽  
Author(s):  
Katsura Yamada
Keyword(s):  
New Taxa ◽  
Northern Hemisphere ◽  
High Latitude ◽  
Water Mass ◽  
Japan Sea ◽  
The Sea Of Japan ◽  
Central Japan ◽  
Marine Deposits ◽  
Japan Sea Proper Water ◽  
The Japan Sea

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.

scholarly journals The Structure and Formation Mechanism of Transversal Cloud Bands Associated with the Japan-Sea Polar-Airmass Convergence Zone

2010 ◽  
Vol 88 (4) ◽  
pp. 625-648 ◽  
Author(s):  
Hisaki EITO ◽  
Masataka MURAKAMI ◽  
Chiashi MUROI ◽  
Teruyuki KATO ◽  
Syugo HAYASHI ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Japan Sea ◽  
Convergence Zone ◽  
The Japan Sea

scholarly journals Climatic response of snow depth to recent warmer winter seasons in heavy-snowfall areas in Japan

2004 ◽  
Vol 38 ◽  
pp. 299-304 ◽  
Author(s):  
Masaaki Ishizaka
Keyword(s):  
Snow Depth ◽  
Japan Sea ◽  
Japan Meteorological Agency ◽  
Temperate Climate ◽  
The Sea Of Japan ◽  
Heavy Snowfall ◽  
Maximum Increase ◽  
Maximum Snow Depth ◽  
The Japan Sea ◽  
Meteorological Observations

AbstractIn heavy-snowfall areas facing the Sea of Japan, winter seasons with lower volumes of snow occurred from 1986/87 to 1999/2000. In this paper, the changes induced by these warmer winters in snowy areas in Japan are investigated using two datasets. One set was normalized for the period 1971–2000 from manned surface meteorological observations by the Japan Meteorological Agency, and the other set was for 1961– 90. Winter climatic monthly values for the first dataset were thought to be affected by the warmer winter seasons since almost half the relevant period coincides with them. By comparing each monthly climatic value in both datasets, the following results were obtained: (1) At each meteorological observation site the bimonthly average temperature fromJanuary to February increased and the amounts of increase were about 0.4°C on average. (2) The bimonthly maximum snow depth for the same period increased at a number of sites, but usually by only a few centimeters, the maximum increase being 0.05 m. (3) In contrast, the decreases in snow depth in heavy-snowfall areas facing the Japan Sea, which belong to a temperate climate zone, were large, ranging from about 0.05 to 0.22 m in climatic bimonthly maximum snow depth during January and February. The last result shows that snow covers in such warm snowy areas are very sensitive to climatic changes. An attempt is also made in this paper to estimate the amounts of decrease in snow depth from the increases in air temperature and the decreases in precipitation amounts.

scholarly journals Estimation of primary production in the northwestern part of the Sea of Japan by ship- and satellite-based observations

2019 ◽  
Vol 59 (1) ◽  
pp. 45-55
Author(s):  
V. I. Zvalinsky ◽  
P. V. Lobanova ◽  
P. Ya. Tishchenko ◽  
V. B. Lobanov
Keyword(s):  
Primary Production ◽  
Japan Sea ◽  
The Sea Of Japan ◽  
Northwestern Part ◽  
In Situ Data ◽  
The North ◽  
Assimilation Number ◽  
The Japan Sea ◽  
Main Production ◽  
Derived Data

In this paper, we analyzed data of POI FAB RAS cruise (No. 33) held on «Akademik M.A. Lavrentyev» vessel in the northwestern part of the Japan Sea in May 2004 and compared them with satellite derived data from Climate Change Initiative Ocean Colour (CCI-OC) and Ocean productivity databases. The following in situ data were used for the analysis: CTD-data, assimilation number, nutrients (P, N, Si) and chlorophyll a (Chl). Ship assessments of Chl in the first optical layer were in average 0.5±0.58 mg/m3, while satellite Chl were nearly twice more – 0.95±0.36 mg/m3. Ship assessments of primary production (PP) were 1870±900 mg C/m2day that is 1.5 times larger than satellite derived data - 1226±432. Vertical profiles of nutrients, temperature and Chl showed that main mass of Chl was concentrated in a layer from 20 to 45 m, where the main production is formed. According to values of assimilation number, main production formed in a layer of 0-55 m in the south of the region and 0-30 m in the north. Weak correlation between ship and satellite PP values found in this paper may be explained by low accuracy of satellite derived estimation.

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