Time series of seasonal variation of primary productivity at station KNOT (44°N, 155°E) in the sub-arctic western North Pacific

Abstract The Coastal Oyashio (CO) carries the cold, fresh, and relatively light water mass called the Coastal Oyashio Water (COW) westward along the southeastern coast of Hokkaido in winter and spring. To investigate dynamics of the CO and its seasonal variation, model experiments are executed using a western North Pacific general circulation model with horizontal resolutions of approximately 2 and 6 km. The 2-km resolution model reproduces the properties of COW with temperature of 0°–2°C and salinity of 32.2–32.6 and reproduces its distribution. COW is less dense than offshore water by 0.2 kg m−3, and it forms a surface-to-bottom density front with a width of 10 km near the shelf break. The CO appears as a baroclinic jet current along the front with a maximum velocity of approximately 40 cm s−1. The velocity and density structures and the front location relative to bathymetry indicate that the CO can be understood in terms of a simplified dynamical model developed for the shelfbreak front in the Middle Atlantic Bight. In contrast to the 2-km resolution model, the 6-km model cannot realistically reproduce the COW distribution. This is because only the 2-km model can represent the sharp density structure of the shelfbreak front and the accompanying CO. The CO exists during the limited period from January to April. This is directly connected with seasonal variation of the COW inflow from the Okhotsk Sea to the North Pacific Ocean through the Nemuro and Kunashiri Straits, indicating that the seasonal variation of the CO is ultimately controlled by the variation of the circulation in the Okhotsk Sea induced by the monsoon.

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The Seasonal Variation of the Good Fishing Area of Salmon and the Movements of Water Masses in the Waters of Western North Pacific-I

NIPPON SUISAN GAKKAISHI ◽

10.2331/suisan.22.511 ◽

1957 ◽

Vol 22 (9) ◽

pp. 511-514

Author(s):

Kisaburo TAGUCHI

Keyword(s):

Seasonal Variation ◽

North Pacific ◽

Western North Pacific ◽

Water Masses ◽

Fishing Area

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Time-series observations of 210Po and 210Pb radioactivity in the western North Pacific

Journal of Radioanalytical and Nuclear Chemistry ◽

10.1007/s10967-014-3141-y ◽

2014 ◽

Vol 301 (2) ◽

pp. 461-468 ◽

Cited By ~ 6

Author(s):

Hajime Kawakami ◽

Makio C. Honda ◽

Shuichi Watanabe ◽

Toshiro Sino

Keyword(s):

Time Series ◽

North Pacific ◽

Western North Pacific

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Seasonal variation in total inorganic carbon and its controlling processes in surface waters of the western North Pacific subtropical gyre

Marine Chemistry ◽

10.1016/s0304-4203(01)00023-8 ◽

2001 ◽

Vol 75 (1-2) ◽

pp. 17-32 ◽

Cited By ~ 31

Author(s):

Masao Ishii ◽

Hisayuki Y Inoue ◽

Hidekazu Matsueda ◽

Shu Saito ◽

Katsuhiko Fushimi ◽

...

Keyword(s):

Seasonal Variation ◽

Surface Waters ◽

North Pacific ◽

Western North Pacific ◽

Inorganic Carbon ◽

Subtropical Gyre ◽

Total Inorganic Carbon ◽

North Pacific Subtropical Gyre ◽

Controlling Processes

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Enhancement of primary productivity in the western North Pacific caused by the eruption of the Miyake-jima Volcano

Geophysical Research Letters ◽

10.1029/2003gl018790 ◽

2004 ◽

Vol 31 (6) ◽

pp. n/a-n/a ◽

Cited By ~ 50

Author(s):

Mitsuo Uematsu ◽

Mitsuhiro Toratani ◽

Mizuo Kajino ◽

Yasushi Narita ◽

Yasuhiro Senga ◽

...

Keyword(s):

Primary Productivity ◽

North Pacific ◽

Western North Pacific

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Western North Pacific Typhoons with Concentric Eyewalls

Monthly Weather Review ◽

10.1175/2009mwr2850.1 ◽

2009 ◽

Vol 137 (11) ◽

pp. 3758-3770 ◽

Cited By ~ 47

Author(s):

Hung-Chi Kuo ◽

Chih-Pei Chang ◽

Yi-Ting Yang ◽

Hau-Jang Jiang

Keyword(s):

Time Series ◽

North Pacific ◽

Western North Pacific ◽

Maximum Intensity ◽

Passive Microwave ◽

Intensity Change ◽

Secondary Eyewall Formation ◽

Peak Intensity ◽

Typhoon Intensity ◽

Concentric Eyewalls

Abstract This study examines the intensity change and moat dynamics of typhoons with concentric eyewalls using passive microwave data and best-track data in the western North Pacific between 1997 and 2006. Of the 225 typhoons examined, 55 typhoons and 62 cases with concentric eyewalls have been identified. The data indicate that approximately 57% of category 4 and 72% of category 5 typhoons possessed concentric eyewalls at some point during their lifetime. While major typhoons are most likely to form concentric eyewalls, the formation of the concentric structure may not be necessarily at the lifetime maximum intensity. Approximately one-third of concentric eyewall cases are formed at the time of maximum intensity. The moat is known to be heavily influenced by the subsidence forced by the two eyewalls. Rozoff et al. proposed that the rapid filamentation dynamics may also contribute to the organization of the moat. This paper examines the possibility of rapid filamentation dynamics by devising a filamentation moat width parameter. This parameter can be computed from the best-track typhoon intensity and the passive microwave satellite-estimated inner eyewall radius for each typhoon with concentric eyewalls. The filamentation moat width explains 40% of the variance of the satellite-observed moat width in the group with concentric eyewall formation intensity greater than 130 kt. The typhoon intensity time series in both the concentric and nonconcentric composites are studied. The time series of intensity is classified according to the 24-h intensity change before and after the concentric eyewalls formation. The averaged concentric eyewall formation latitudes in the groups with negative intensity change before concentric eyewall formation are at higher latitudes than that of the positive intensity change groups. Intensity of the concentric typhoons tends to peak at the time of secondary eyewall formation, but the standard model of intensification followed by weakening is valid for only half of the cases. Approximately 74% of the cases intensify 24 h before secondary eyewall formation and approximately 72% of the cases weaken 24 h after formation. The concentric composites have a much slower intensification rate 12 h before the peak intensity (time of concentric formation) than that of the nonconcentric composites. For categories 4 and 5, the peak intensity of the concentric typhoons is comparable to that of the nonconcentric typhoons. However, 60 h before reaching the peak the concentric composites are 25% more intense than the nonconcentric composites. So a key feature of concentric eyewall formation appears to be the maintenance of a relatively high intensity for a longer duration, rather than a rapid intensification process that can reach a higher intensity.

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