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During the March 11, 2011 Tohoku tsunami, some Japanese and Russian tide gauges in the Sea of Japan recorded sea level disturbances with periods of several to 10 min and amplitudes of several to a few tens of centimeters starting immediately after the earthquake. Tsunami travel times computed from the 2011 source in the Pacific Ocean to these stations are 1-2 h. To examine the cause of the observed tsunami forerunners and to reproduce them, we carried out tsunami numerical computations from three kinds of coseismic seafloor deformation: the vertical displacement in the tsunami source area in the Pacific Ocean, the vertical displacement extending in the Sea of Japan, and the vertical displacement including the effects of the horizontal displacement and the seafloor slope in both the Pacific Ocean and the Sea of Japan. Only the last source reproduced the observed tsunami forerunners. This indicates that the tsunami forerunners were produced by the horizontal displacement of fault motion and the seafloor slope in the Sea of Japan. For the tide gauge records in Japan, the forerunners with periods longer than 2 min were well reproduced by the tsunami simulation. The shorter-period components may be induced by seismic ground shakings. For the tide gauge records in Russia, the agreement between the observed and computed waveforms was less satisfactory, probably because of less accurate and coarser bathymetry data. [ABSTRACT FROM AUTHOR]

During study of the physical nature and potential precursor features of the El Niño phenomenon in the Pacific, it was found that a negative large-scale temperature anomaly on the Indian Ocean surface may be one of its significant precursors. This anomaly appears prior to the occurrence of El Niño and is accompanied by growth in atmospheric pressure. It gradually extends eastwards along the equator until the zone of planetary convection in the area of the Indonesian Region. The west wind that emerges on the eastern peripherals of the mentioned pressure anomaly leads to reversal of the Pacific segment of the Walker equatorial atmospheric circulation and to a subsequent change in the zonal thermal dipole polarity in the tropical zone of the Pacific (the latter means culmination of the El Niño phenomenon). In addition to the mentioned thermobaric anomaly in the Indian Ocean, other obvious signs of large-scale pressure anomalies have been found in the global atmospheric pressure field; these anomalies may be interpreted as manifestations of the intradecadal global oscillation in the dynamics of the modern climatic system. It is suggested that the whole known complex of events related to the El Niño phenomenon in the Pacific is a consequence and a regional link of the planetary structure of this global atmospheric phenomenon. [ABSTRACT FROM AUTHOR]

The Singapore Regional Waters (SRW) is one of the more complex tidal regions in the world. This complexity is caused by various factors including the interaction of the Indian and Pacific oceans with their mainly semi-diurnal and diurnal tide, respectively, complicated coastline geometry, small islands and sharply varying bottom topography. Tidal data analysis is hampered by the lack of reliable coastal stations with long-term water level records while numerical tidal modelling studies suffer from lack of accurate high-resolution bathymetry data and uncertainty in the prescription of the tidal open boundary forcing. The present study combines numerical modelling with available along-track satellite altimetry data and a limited set of reliable coastal stations. It proposes a structured approach to study the sensitivity of tidal propagation and interactions to parameters like the prescription of tidal forcing at the open ocean boundaries, local depth information and seabed roughness. To guide and facilitate this analysis, the open-source software environment OpenDA for sensitivity analysis and simultaneous parameter optimisation is used. In a user-controlled way, the vector difference error in tidal representation could so effectively be reduced by ~50%. The results confirm the benefit of using OpenDA in guiding the systematic exploration of the modelled tide and reducing the parameter uncertainties in different parts of the SRW region. OpenDA is also shown to reduce the repetitive nature of simultaneous parameter variation. Finally, the behaviour of the tide in the region and its sensitivities to changes in tidal boundary forcing and to local depth and friction variation in the narrow regions of the Malacca Strait is now much better understood. With most of the systematic errors reduced in the numerical model as a result of the sensitivity analysis, it is expected that the model can be applied to study tide-surge interaction and is much better suited for later application in combination with data assimilation techniques such as Kalman filtering for which systematic model errors should be minimal. [ABSTRACT FROM AUTHOR]

Two deep-sea moorings were deployed respectively in the east area and the west area of Chinese Pioneer Area (CPA) in the tropic east Pacific to monitor the regional deep-sea dynamics below 600 meters above bottom (mab) from July 1997 to Oct. 1999. Results of statistics, spectral estimate and correlation analysis of the Iow-passed velocity data show that time scales of low-frequency components of the near-bottom currents are 25∼120 days, in which 51-day period dominates the lower band of the frequency domain. Topographic features have obvious effect on low-frequency currents below 50 mab; modulations of the bottom-intensified sheared mean flow to the low-frequency currents are the dynamic mechanism of the frequency shift that occurs in both the east-area and the west-area. [ABSTRACT FROM AUTHOR]

Focuses on research on extracts from manganese nodules and ooze from the Central Pacific deep sea floor. Use of chromatogram-mass spectrum for analysis; Finding that most of the biomarker molecules are of the low-mature type; Ratios including those for "A"/C, CPI, hopane, Tm/Ts, moretane, and arene TA(I)/TA(I+II); The methyl-phenanthrene index (MPI1); Suggestion that the hydrothermal activities on the ocean floor ease the decomposition of organic matter in the sediment and leads to the generation and migration of hydrocarbon, resulting in manganese nodules and ooze; Implication of this discovery for understanding the mechanisms of hydrocarbon generation and for expanding the potential of offshore oil and gas exploration.

Discusses the near-seafloor magnetic anomalies recorded over the southern East Pacific Rise, which correlate with independent estimates of geomagnetic intensity during the past 780 kyr. Pattern of absolute paleointensity of seafloor glass samples from the area agreeing with the dipole intensity pattern for the past 50 kyr; Estimation of the ages of surficial lava flows in the region; Record of geomagnetic intensity preserved in the oceanic crust providing a higher-time-resolution record of crustal accretion process at mid-ocean ridges.

The article discusses the study by Pälike and colleagues which demonstrates the cyclic changes in the rate of burial of biogenic calcium carbonate at the bottom of the Pacific Ocean 43 million to 33 million years ago. It states that the cyclic changes reveal the dramatic changes in carbonate burial and their relationship with climate. It says that the study also found that geologically rapid oscillations occurred in calcium carbonate accumulation of the Pacific sea floor.

The article reports on the use of operated vehicle Nereus during the scientists' exploration of Mariana Trench in the Pacific Ocean in May 31, 2009. It states that for the first time in a decade, the scientists went through the deepest part of Pacific Ocean with the use of Nereus, which dived 10,902 meters to the bottom of Marian Trench. It notes that the gadget, which was made by researchers from the Woods Hole Oceanographic Institution in Massachusetts, is use to capture images under the sea.

The article discusses how ancient ooze from the bottom of the Pacific Ocean can provide evidence that the deep ocean sequestered vast amounts of carbon dioxide (CO2) during a previous ice age which cooled the planet Earth. Topics include research by Samuel Jaccard and colleagues who obtained data from trace elements within ancient ooze and revised a previous hypothesis regarding the nutrient dynamics of the ocean.

Relates that the research expedition, Ocean Drilling Program, plans to dig deep in the Pacific Ocean for microorganisms that live beneath the sea floor. Goal of the expedition to increase knowledge regarding the microbes.