scholarly journals Long-term acoustic tomography measurement of ocean currents at the northern part of the Luzon Strait

2010 ◽  
Vol 37 (7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Naokazu Taniguchi ◽  
Arata Kaneko ◽  
Yaochu Yuan ◽  
Noriaki Gohda ◽  
Hong Chen ◽  
...  
Keyword(s):  
Luzon Strait ◽  
Ocean Currents ◽  
Acoustic Tomography

Chilling Out

2018 ◽  
Author(s):  
Roy Livermore
Keyword(s):  
Plate Tectonics ◽  
Volcanic Eruptions ◽  
Atmospheric Temperature ◽  
Ocean Currents ◽  
Mountain Ranges ◽  
Continental Rifts ◽  
Earth’S Climate ◽  
The One ◽  
Tectonic Forces

The Earth’s climate changes naturally on all timescales. At the short end of the spectrum—hours or days—it is affected by sudden events such as volcanic eruptions, which raise the atmospheric temperature directly, and also indirectly, by the addition of greenhouse gases such as water vapour and carbon dioxide. Over years, centuries, and millennia, climate is influenced by changes in ocean currents that, ultimately, are controlled by the geography of ocean basins. On scales of thousands to hundreds of thousands of years, the Earth’s orbit around the Sun is the crucial influence, producing glaciations and interglacials, such as the one in which we live. Longer still, tectonic forces operate over millions of years to produce mountain ranges like the Himalayas and continental rifts such as that in East Africa, which profoundly affect atmospheric circulation, creating deserts and monsoons. Over tens to hundreds of millions of years, plate movements gradually rearrange the continents, creating new oceans and destroying old ones, making and breaking land and sea connections, assembling and disassembling supercontinents, resulting in fundamental changes in heat transport by ocean currents. Finally, over the very long term—billions of years—climate reflects slow changes in solar luminosity as the planet heads towards a fiery Armageddon. All but two of these controls are direct or indirect consequences of plate tectonics.

Using acoustic tomography to monitor deep ocean currents in the eastern Gulf of Mexico

OCEANS 2009 ◽  
2009 ◽  
Author(s):  
D. A. Rosenfield ◽  
J. W. Caruthers ◽  
D. A. Nechaev ◽  
G. E. Ioup ◽  
J. W. Ioup ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Deep Ocean ◽  
Ocean Currents ◽  
Acoustic Tomography ◽  
Eastern Gulf Of Mexico ◽  
Deep Ocean Currents

Evaluation of Leakage Probability of Non-Asbestos Fiber Sheet Gasket at Elevated Temperature Based on Percolation Theory

2010 ◽  
Author(s):  
Masahiro Hagihara ◽  
Hirokazu Tsuji ◽  
Atsushi Yamaguchi
Keyword(s):  
High Temperature ◽  
Percolation Theory ◽  
Life Prediction ◽  
Prediction Method ◽  
Acoustic Tomography ◽  
Leakage Path ◽  
Temperature Environment ◽  
Fiber Sheet ◽  
Bolted Flange

A long-term life prediction method for a compressed fiber sheet gasket under a high-temperature environment is studied. Non-asbestos compressed fiber sheet gaskets are now being used as a substitute for asbestos in the bolted flange joint, for instance petrochemical factories. Consequently, there is a real need for a technology to predict the lifetime of non-asbestos compressed fiber sheet gaskets quantitatively. In this report, the facing surface of the gasket and flange is visualized with scanning acoustic tomography (SAT). Voids were observed on the facing surface of the gasket and increased with the increase in exposure time at high temperature. If a leakage path for inner fluids is created by the increasing number of voids, the leak occurs on the facing surface of the gasket. The probability of a leak due to voids and the lifetime of this gasket are predicted by applying the percolation theory, which describes the connectedness of clusters.

scholarly journals Water Temperature Observation by Coastal Acoustic Tomography in Artificial Upwelling Area

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2655 ◽  
Author(s):  
Haocai Huang ◽  
Yong Guo ◽  
Zhikun Wang ◽  
Yun Shen ◽  
Yan Wei
Keyword(s):  
Temperature Field ◽  
Field Observation ◽  
Temperature Sensors ◽  
Acoustic Tomography ◽  
Mapping Accuracy ◽  
Temperature Observation ◽  
Comparison Results ◽  
Upwelling Area ◽  
Continuous Temperature

Artificial upwelling is a geoengineering method to repair and improve marine ecosystems, and its operation requires long-term and continuous temperature field observation. However, existing methods are rarely seen to accomplish such observation. In this study, we investigate the coastal acoustic tomography (CAT) to obtain the long-term horizontal temperature field of an artificial upwelling area in an anechoic tank. We conduct four sets of experiments with different CAT station numbers and compare their data with those collected from temperature sensors. By analyzing the travel time from the CAT experiments, the horizontal temperature field of the upwelling area could be mapped. The CAT results and the comparison results show that the surface temperature of the observed area decreases by approximately 3 °C after upwelling, while the temperature of where the CAT is deployed decreases by about 1 °C; the temperature is lowest at the center of the upwelling area. Increasing the number of stations and station spacing would improve the temperature mapping accuracy. Therefore, the feasibility of using the CAT system to observe artificial upwelling is proved valid. This study indicates the potential application of CAT in temperature field observation in artificial upwelling area in the sea.

scholarly journals Response of upper ocean currents to typhoons at two ADCP moorings west of the Luzon Strait

2010 ◽  
Vol 28 (5) ◽  
pp. 1002-1011 ◽  
Author(s):  
Fei Chen ◽  
Yan Du ◽  
Li Yan ◽  
Dongxiao Wang ◽  
Ping Shi
Keyword(s):  
Luzon Strait ◽  
Ocean Currents ◽  
Upper Ocean

Long-term measurement of temperature variabilities off Mindanao Island by the ocean acoustic tomography

1995 ◽  
Vol 51 (3) ◽  
pp. 327-339 ◽  
Author(s):  
Gang Yuan ◽  
Iwao Nakao ◽  
Hidetoshi Fujimori ◽  
Arata Kaneko
Keyword(s):  
Acoustic Tomography ◽  
Ocean Acoustic Tomography ◽  
Long Term Measurement

Inversion of temperature vertical structure by ocean acoustic tomography data in the Luzon Strait

2012 ◽  
Vol 131 (4) ◽  
pp. 3314-3314
Author(s):  
Ju Lin ◽  
Araka Kaneko ◽  
Naokazu Taniguchi ◽  
Huan Wang ◽  
Noriaki Gohda
Keyword(s):  
Vertical Structure ◽  
Luzon Strait ◽  
Acoustic Tomography ◽  
Ocean Acoustic Tomography ◽  
Tomography Data

scholarly journals Variability in the Deep Overflow through the Heng-Chun Ridge of the Luzon Strait

2019 ◽  
Vol 49 (3) ◽  
pp. 811-825 ◽  
Author(s):  
Ruijie Ye ◽  
Chun Zhou ◽  
Wei Zhao ◽  
Jiwei Tian ◽  
Qingxuan Yang ◽  
...  
Keyword(s):  
Deep Water ◽  
Volume Transport ◽  
Luzon Strait ◽  
Bottom Current ◽  
Detailed Structure ◽  
Intraseasonal Variations ◽  
First Time ◽  
Water Overflow ◽  
Main Entrance

AbstractThe deep water overflow at three gaps in the Heng-Chun Ridge of the Luzon Strait is investigated based on long-term continuous mooring observations. For the first time, these observations enable us to assess the detailed structure and variability in the deep water overflow directly spilling into the South China Sea (SCS). The strong bottom-intensified flows at moorings WG2 and WG3 intrude into the deep SCS with maximum along-stream velocities of 19.2 ± 9.9 and 15.2 ± 6.8 cm s−1, respectively, at approximately 50 m above the bottom. At mooring WG1, the bottom current revealed spillage into the Luzon Trough from the SCS. The volume transport estimates are 0.73 ± 0.08 Sv at WG2 and 0.45 ± 0.02 Sv at WG3, suggesting that WG2 is the main entrance for the deep water overflow crossing the Heng-Chun Ridge into the SCS. By including the long-term observational results from previous studies, the pathway of the deep water overflow through the Luzon Strait is also presented. In addition, significant intraseasonal variations with dominant time scales of approximately 26 days at WG2 and WG3 have been revealed, which tend to be enhanced in spring and may reverse the deep water overflow.

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