Density Currents

Density Currents

 

currents in the seas and oceans caused by the horizontal pressure gradients resulting from the nonuniform distribution of density in seawater. Permanent density currents, along with wind currents, play an important part in the overall circulation system of the surface waters of the world ocean. In the deep layers, where wind-driven currents are attenuated, density currents predominate. They are characteristic in straits between bodies of water with different densities. Owing to the Coriolis force, density currents move perpendicular to the horizontal density gradients.

The theory of density currents is based on the circulation theory of the Norwegian geophysicist V. F. K. Bjerknes. The theory was elaborated by the Norwegian B. Helland-Hansen, the Swede J. W. Sandström, and the Soviet scientist N. N. Zubov, who propounded the dynamic method of calculating sea currents from the distribution of water density.

References in periodicals archive ?
Likewise, its seismic activity has been dominated by low frequency events associated with degassing at the summit and signals of rockfall and small-volume pyroclastic density currents (PDCs) or pyroclastic flow generated by the collapsing front and margins of lava flows on the Miisi, Bonga and Basud gullies and intermediary channels.
Seismology (Phivolcs) maintained that it is still possible to have sudden eruptions, lava collapses, pyroclastic density currents, and ash fall events.
The volcano can be expected to continue generating volcanic earthquakes, magmatic gas output and weak surface processes such as sporadic degassing and lava effusion events, steam-driven explosions, rockfall and pyroclastic density currents, while shallow remnant magma rests within the edifice,' it said.
Fine dust from pyroclastic density currents, due to its small size, can be suspended in the air, and may eventually reach residential areas outside the danger zone, she warned.
Lahar flow from Mayon, composed of 9 million cubic metre pyroclastic density currents and 1.
A total of two (2) explosion-type earthquakes corresponding to the vertical column eruptions, fifteen (15) tremor events, some corresponding to lava fountaining episodes, thirty five (35) rockfall events and (2) pyroclastic density currents or PDCs from lava collapse were recorded by Mayon's seismic monitoring network," it said.
on Monday, lasting five and seven minutes respectively and producing rock falls and small-volume pyroclastic density currents.
The 2016 edition of the esteemed series features lengthy articles on the fluid mechanics of heart valve replacements and pyroclastic density currents, and the dynamics of vortex pairs, microtubules, and motor protein assemblies.
Formally, following standard techniques and considering the ZPF properties, at each position there is a diffusion of probability density currents (Pv), in such a way that
This model has the capability of predicting long term sedimentation in huge reservoirs by considering the occurrence probability of one dimensional density currents.
At 9:09 pm, on November 13,1985, NRV, a small volume of mixed andesite and dacite magma was ejected as pumice fall and pyroclastic density currents during the Plinian eruption that pumped tephra into the atmosphere for more than 30 km (20 mi)--a commercial flight witnessed this eruption.
We took on the modeling of enormously complicated pyroclastic density currents, notably the classic, notorious May 1980 lateral blast that destroyed 500 square kilometers of forested terrain at Mount St.