50 research outputs found
Potential biogeochemical effects from vigorous internal tides generated in Luzon Strait: A case study at the southernmost coast of Taiwan
No full textPotential biogeochemical effects from vigorous internal tides generated in the Luzon Strait: A case study at the southernmost coast of Taiwan.
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Author's reply to Comments on "Artifacts introduced into the calculation of the mixing ratios of seawater end-members using T-S properties"
No full textDepth distribution of δ13 of dissolved ΣCO2 in seawater off eastern Taiwan: effects of the Kuroshio current and its associated upwelling phenomenon
No full textDepth distributions of alkalinity, TCO2 and δ13CTCO2 at SEATS time-series site in the northern South China Sea
No full textDistributions and variations of dissolved organic carbon in the Taiwan Strait and Taiwanese rivers
No full textDissolved organic carbon (DOC) is one of the largest pools of carbon in the ocean, and is of the same size as the carbon dioxide in the atmosphere. Estuaries connecting the land and the ocean are one of the most important DOC sources to the ocean, and play an important role in the global carbon cycle. Because of their complex chemical, physical, geological and biological properties, estuaries have become rich ecological environment. In this study, we investigated the seasonal distributions of DOC in the Taiwan Strait (TS) and Taiwanese rivers, aiming to understand the distributions and variations of DOC in different seasons.
The results show that DOC concentrations are generally the highest in the upper estuary, and then decrease downstream due to mixing with the low DOC seawater. The process of river flow constantly accumulates terrestrial material, and the DOC shows positive correlations with Chl. a, CH4 and BOD (Biochemical Oxygen Demand), suggesting that biological activities and pollutions could be sources of DOC in the estuary. The DOC concentrations (salinity<1) varied in dry (Nov.-Apr.) and wet (May-Oct.) seasons with ranges of 42-1185 \uce\ubcM (mean=245\uc2\ub1254\uce\ubcM; n=32) and 18-565 \uce\ubcM (mean=183\uc2\ub1151\uce\ubcM; n=24), respectively. The total DOC flux of 25 rivers is 87.8 Gg C/yr, which can be translated to the fluxes of all rivers in Taiwan to be 101.9 Gg C/yr. The amount of DOC flux in Taiwan is only about 0.07% of the tropical area, but the per unit area flux (3.92 gC /m2 /yr) is almost twice those of the tropical rivers (2.13 gC /m2 /yr). In Taiwan, the population density and land use are higher than the world average. Consequently, the impacts of the environment by human activities reveal the utmost export of DOC, and need further investigation.
Next, in the TS, the DOC shows significant negative correlations with Sigma-T, and the distributions of DOC are mainly controlled by physical mixing in both winter and summer. In the western TS, DOC concentration is relatively high, compared to the eastern part, and is because of low temperature and salinity, but high DOC coastal China current flowing from north to south. DOC concentration decreases with increasing depth owing to the intrusion at depth by the Kuroshio, which contains relatively low DOC.
In winter, the import of coastal China current brings more nutrients from north to south, and supports the growth of bacteria which depletes the DOC and oxygen. As the result, DOC decomposition rate is higher in winter than in summer. The TS\ue2s DOC fluxes in summer (northern TS: 3.85\uc31012mol C/yr\uef\ubcsouthern TS: 3.75\uc31012mol C/yr) are higher than in winter (northern TS: 3.69\uc31012mol C/yr\uef\ubcsouthern TS: 2.84\uc31012mol C/yr). Main differences are due to the prevailing southwest monsoon winds in summer transporting more water from the South China Sea to the TS, and the river discharge brings more terrigenous organic matters into the TS. Therefore, the DOC export in summer is higher than in winter
Island-based catchment-The Taiwan example
Full text linkRapid economic and industrial development in Taiwan over the past five decades has elevated the island's standing and earned it a place in the group known as the Four Small Dragons of Asia. Such growth, however, has been at the expense of the environment. There are currently nearly 23 million people juggling for space on the small island of 35,873 km(2). Aggravating the matter further, the central mountain ranges and hills take up 73.6% of the land area with some 156 peaks surpassing 3,000 m. As a result, most people live in coastal plains which amount to only 9,490 km(2). Pressure to move people inland has led to road construction and deforestation, both of which have contributed to an already high denudation rate of topsoil. As a consequence of this, thirteen rivers in Taiwan are now ranked among the top 20 worldwide in terms of sediment yield. Aside from this, the frequency of both floods and droughts increased prior to 1990, perhaps because of deforestation and global warming. Fortunately, the new conservation-orientated forest management policy of 1991 has alleviated the problem, somewhat, and the occurrence of floods and droughts has since decreased. The problem of water shortage, however, has worsened because of the warming trend in atmospheric temperature. Damming may ameliorate the water shortage problem but may affect the shoreline stability, as well as the ecology and water quality in the estuaries. Furthermore, these detrimental effects may go far beyond the estuaries, and even fisheries on the continental shelves may be affected
La struttura Tensegrity T-Bar soggetta ad instabilità globaleThe T-Bar tensegrity bar subjected to global instability
No full textIn the present work the behavior of a fundamental Tensegrity structure is analyzed: the T-Bar.
This structural typology has been already studied by one of the author. In this work a generalizations
of previous obtained results is presented due to the accounting for the global instability phenomenon
that was neglected in previous studies. The goal of the study herein presented is to establish
when the use of a T-Bar can lead to a mass saving when compared with a solid bar subjected
to the same load and having the same length
Exchange of water masses between the East China Sea and the Kuroshio off northeastern Taiwan
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