Seasonal Variations and Long-term Trends of the Coastal Upwelling along the Southwestern Coast of the East Sea/Japan Sea

2018 ◽  
Vol 85 ◽  
pp. 471-475
Author(s):  
Chang-Woong Shin ◽  
Dong Guk Kim ◽  
Chan Joo Jang
Keyword(s):  
Seasonal Variations ◽  
Coastal Upwelling ◽  
Japan Sea ◽  
East Sea ◽  
Long Term Trends

Recent trends in air-sea CO2 fluxes and ocean acidification in the Arabian Sea

2021 ◽  
Author(s):  
Zouhair Lachkar ◽  
Michael Mehari ◽  
Alain De Verneil ◽  
Marina Lévy ◽  
Shafer Smith
Keyword(s):  
Ocean Acidification ◽  
Arabian Sea ◽  
Coastal Upwelling ◽  
Biogeochemical Model ◽  
Atmospheric Concentration ◽  
Physical Forcing ◽  
Freshwater Fluxes ◽  
Ocean Biogeochemical Model ◽  
Long Term Trends

<p>Recent observations and modeling evidence indicate that the Arabian Sea (AS) is a net source of carbon to the atmosphere. Yet, the interannual variability modulating the air-sea CO<sub>2</sub> fluxes in the region, as well as their long-term trends, remain poorly known. Furthermore, while the rising atmospheric concentration of CO<sub>2</sub> is causing surface ocean pH to drop globally, little is known about local and regional acidification trends in the AS, a region hosting a major coastal upwelling system naturally prone to relatively low surface pH. Here, we simulate the evolution of air-sea CO<sub>2</sub> fluxes and reconstruct the progression of ocean acidification in the AS from 1982 through 2019 using an eddy-resolving ocean biogeochemical model covering the full Indian Ocean and forced with observation-based winds and heat and freshwater fluxes. Additionally, using a set of sensitivity simulations that vary in terms of atmospheric CO<sub>2</sub> levels and physical forcing we quantify the variability of fluxes associated with both natural and anthropogenic CO<sub>2</sub> and disentangle the contributions of climate variability and that of atmospheric CO<sub>2</sub> concentrations to the long-term trends in air-sea CO<sub>2</sub> fluxes and acidification. Our analysis reveals a strong variability in the air-sea CO<sub>2</sub> fluxes and pH on a multitude of timescales ranging from the intra-seasonal to the decadal. Furthermore, a strong progression of ocean acidification with an important penetration into the thermocline is simulated locally near the upwelling regions. Our analysis also indicates that in addition to the increasing anthropogenic CO<sub>2</sub> concentrations in the atmosphere, recent warming and monsoon wind changes have substantially modulated these trends regionally.</p>

scholarly journals <i>Letter to the Editor</i>: Spatial and seasonal variations of the <i>fo</i>F2 long-term trends

1999 ◽  
Vol 17 (9) ◽  
pp. 1239-1243 ◽  
Author(s):  
A. D. Danilov ◽  
A. V. Mikhailov
Keyword(s):  
Seasonal Variations ◽  
Critical Frequency ◽  
Geomagnetic Latitude ◽  
Seasonal Effect ◽  
Ionospheric Disturbances ◽  
Trend Magnitude ◽  
Letter To The Editor ◽  
Critical Frequency Fof2 ◽  
Long Term Trends

Abstract. Using a method suggested by the authors earlier, the long-term trends of the F2-layer critical frequency, foF2 are derived for a set of ionospheric stations with a wide latitudinal and longitudinal coverage. All the trends are found to be negative. A pronounced dependence on geomagnetic latitude is found, the trend magnitude increasing with the latter. No globe scale longitudinal effect in trends is detected. For the majority of the stations there is also a pronounced seasonal effect, the trend magnitude being higher in summer than in winter.Key words. Ionosphere (ionospheric disturbances; mid-latitude ionosphere)

scholarly journals Long-term trends of oxygen concentration in the waters in bank and shelves of the Southern Japan Sea

2021 ◽  
Author(s):  
Tsuneo Ono
Keyword(s):  
Water Column ◽  
Japan Sea ◽  
Summer Season ◽  
Sea Surface ◽  
Tsushima Strait ◽  
Continental Shelves ◽  
Japan Sea Proper Water ◽  
Long Term Trends ◽  
Wakasa Bay

AbstractWhile multiple studies have investigated oxygen decrease in Japan Sea Proper Water (JSPW; > 300 m in depth), oxygen variation in continental slope and shelf waters (< 300 m) must also be investigated in order to assess its socioecological impacts. In this study, historical oxygen data in the waters of three continental shelves and a bank of Japan Sea, off-Awashima area (AW), Wakasa Bay (WB), East of Tsushima Straight (ETS), and Yamato Bank (YB), were collected and analyzed to assess temporal variation of oxygen in each region from 1960 to 2000s. Significant decreasing trends of oxygen were detected in the waters below 150 m depth in WB and YB, and below 300 m in AW, in the summer season. In winter, a decreasing trend of oxygen was detected throughout the water column from 300 m to the sea surface in WB and YB. In ETS, a deoxygenation trend was detected throughout the water column from the bottom to the sea surface in the summer season, while no trend was detected in winter. The results suggested that oxygen decreases in AW, WB, and YB were the consequence of the upward propagation of the deoxygenation signal from JSPW, while that of ETS was caused by horizontal propagation of deoxygenation signal from the East China Sea. Assuming that the observed trend will continue in future, it is predicted that part of the water in Tsushima Strait area will reach the general sublethal threshold of oxygen (134 μmol kg−1) by the end of this century.

Long-term trends in pelagic environments of the east sea ecosystem

2008 ◽  
Vol 43 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Chung Il Lee ◽  
Jae-Young Lee ◽  
Kwang-Ho Choi ◽  
Sung-Eun Park
Keyword(s):  
East Sea ◽  
Long Term Trends
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