The shoaling mode-2 internal solitary waves in the Pacific coast of Central America investigated by marine seismic survey data

2021 ◽  
Vol 212 ◽  
pp. 104318
Author(s):  
Wenhao Fan ◽  
Haibin Song ◽  
Yi Gong ◽  
Shaoqing Sun ◽  
Kun Zhang ◽  
...  
Keyword(s):  
Central America ◽  
Survey Data ◽  
Solitary Waves ◽  
Pacific Coast ◽  
Seismic Survey ◽  
Internal Solitary Waves ◽  
The Pacific ◽  
Mode 2 ◽  
Marine Seismic

scholarly journals Regional study of mode-2 internal solitary waves in the Pacific coast of Central America using marine seismic survey data

2021 ◽  
Author(s):  
Wenhao Fan ◽  
Haibin Song ◽  
Yi Gong ◽  
Shun Yang ◽  
Kun Zhang
Keyword(s):  
Phase Velocity ◽  
Central America ◽  
Solitary Waves ◽  
Pacific Coast ◽  
Seismic Survey ◽  
Internal Solitary Waves ◽  
Regional Study ◽  
The Pacific ◽  
Dimensionless Amplitude ◽  
Mode 2

Abstract. In this paper, a regional study of the mode-2 internal solitary waves (ISWs) in the Pacific coast of Central America is carried out by using seismic reflection method. The observed relationship between the dimensionless phase velocity and the dimensionless amplitude (DA) of the mode-2 ISWs was analysed. When DA < 1, the dimensionless phase velocity increases with the increasing dimensionless amplitude, divided into two parts with different growth rates. When DA > 1, the dimensionless phase velocity increases with the increasing dimensionless amplitude at a relatively small growth rate. We suggest that the influences of seawater depth (submarine topography), pycnocline depth, and pycnocline thickness on the phase velocity of the mode-2 ISWs in the study area, cause the relationship between the dimensionless phase velocity and the dimensionless amplitude diversified. The observed relationship between the dimensionless wavelength and the dimensionless amplitude of the mode-2 ISWs was also analysed. When DA < 1 and DA > 2, the dimensionless wavelength decreases and increases with the increasing dimensionless amplitude, respectively. Additionally, the seawater depth has a great influence on the wavelength of the mode-2 ISWs in the study area, and overall the wavelength increases with the increasing seawater depth. As for the vertical structure of the amplitude of the mode-2 ISWs in the study area, we find that it is affected by the nonlinearity of the ISWs and the pycnocline deviation (especially the downward pycnocline deviation).

Mode-2 internal solitary waves offshore Central America discovered by seismic oceanography method

2020 ◽  
Author(s):  
Wenhao Fan ◽  
Haibin Song ◽  
Yi Gong ◽  
Shaoqing Sun ◽  
Kun Zhang
Keyword(s):  
Phase Velocity ◽  
Central America ◽  
Solitary Waves ◽  
Kdv Equation ◽  
Seismic Survey ◽  
Internal Solitary Waves ◽  
Acquisition Time ◽  
Apparent Velocity ◽  
Seismic Oceanography ◽  
Mode 2

&lt;p&gt;In the past, most of the internal solitary waves (ISWs) found by seismic oceanography (SO) method were mode-1 ISWs. We discover many mode-2 ISWs in the Pacific coast of Central America by using SO method for the first time. These mode-2 ISWs are convex mode-2 ISWs with the maximum amplitudes of about 10 m, and most of them are ISWs with smaller amplitudes. The pycnocline for the mode-2 ISWs on the shelf (ISW3) is displaced 6.4% of the total seawater depth from the mid-depth of the total seawater. The deviation is large, and it shows a strong asymmetry feature of the peaks and troughs on the seismic profile. This is consistent with the results of previous numerical simulation. Observing the changes in the fine structure of mode-2 ISWs packet through pre-stack migration, it was found that the overall waveform of the three mode-2 ISWs (ISW1, ISW2, and ISW3) on the shelf during the acquisition time period of about 40 seconds is stable. The apparent phase velocity of these mode-2 ISWs calculated by the pre-stack migration section using the Common Offset Gathers is about 0.5 m/s, and their apparent propagation directions are from SW to NE along the seismic line (44 &amp;#176; N, 0&amp;#176; pointing north). The vertical amplitude distribution and estimated apparent velocities of these mode-2 ISWs are basically consistent with the theoretical values &amp;#8203;&amp;#8203;calculated from the KdV equation. By analyzing the apparent velocities of the three mode-2 ISWs (ISW1, ISW3, and ISW5) with relatively small apparent velocity errors, it is found that the apparent velocity of mode-2 ISWs generally increases with the increasing depth of seawater. In addition, the apparent phase velocity of the mode-2 ISWs with a larger maximum amplitude is generally larger. Based on the analysis of hydrological data in the study area, it was found that a strong anticyclone developed on the northwest side of the seismic survey line and a weaker anticyclone developed on the southeast side. These anticyclones will increase the depth of the thermocline in the surrounding seawater. According to previous studies, the deepening of the thermocline (pycnocline) maybe conducive to the generation of mode-2 ISWs.&lt;/p&gt;

Features of internal solitary waves revealed by seismic oceanography data

2020 ◽  
Author(s):  
Haibin Song ◽  
Wenhao Fan ◽  
Shaoqing Sun ◽  
Yongxian Guan ◽  
Kun Zhang ◽  
...  
Keyword(s):  
Phase Velocity ◽  
Central America ◽  
Solitary Waves ◽  
Sand Dunes ◽  
Maximum Amplitude ◽  
Internal Solitary Waves ◽  
Strait Of Gibraltar ◽  
Seismic Oceanography ◽  
Mode 2 ◽  
Reflection Configuration

&lt;p&gt;In this paper, we used the seismic oceanography method to study the structural characteristics of internal solitary waves (ISWs) near the Strait of Gibraltar in the Mediterranean Sea, South China Sea and offshore Central America.&lt;/p&gt;&lt;p&gt;The ISWs near the Strait of Gibraltar are the first mode depressional type, mostly medium amplitude and large amplitude internal solitary waves. The maximum vertical amplitude is up to 74.5m, and the amplitude increases with depth&amp;#65292;the propagation velocity increases with amplitude. It can be determined that the &quot;true&quot; maximum amplitude position is near the pycnocline. After correction, the maximum half-height-width can reach 1721.8m, but there is somewhat different from the theoretical result&amp;#65292;which may be related to the development stability of ISWs. As the solitary wave packet continuously moves eastward, the overall wave width becomes larger, and the vertical velocity becomes smaller. In this paper, seismic oceanography is applied to the analysis of ISWs in the Mediterranean Sea, which further proves the feasibility of using seismic oceanography to study the movement of sea water.&lt;/p&gt;&lt;p&gt;We reprocess some multi-channel seismic (MCS) data which is acquired recently in the Dongsha region of the northeastern South China Sea and we obtain new seismic oceanography data. The research suggest that there are the mode-2 internal solitary wave(ISWs) not just the mode-1 ISWs and a special reflection pattern (hair-like reflection configuration )usually above sand dunes in the seismic images. In new seismic oceanography data, there are some mode-1 ISWs with amplitudes less than 50m and wavelength of 1~5 km and the biggest mode-1 ISWs have the amplitude about 45m. The internal solitary waves packets are not prototypical rank-ordered ISW packets, their soliton amplitudes are smaller than 40. The mode-2 ISWs is well-shaped and its&amp;#8217; amplitude is approximate 30m, the vertical structure height is about 200m.The reflection configuration of water column above sand dunes usually include weak reflection layer-maybe called turbulent bottom boundary layer, and there is hair reflection configuration that must not appear. Whether there will be hair reflection configuration or not may depend on the angle between the seismic line and the sand dunes.&lt;/p&gt;&lt;p&gt;In the region offshore Central America, there are lots of mode-2 ISWs revealed from seismic oceanography data. We combine seismic data with hydrographic data to study the features of ISWs in these different regions. The preliminary results show the phase velocity in SCS is the largest, that in the Strait of Gibraltar is the second and that offshore Central America is the last. The phase velocity depends on the amplitude of ISW. Usually the mode-1 depressional ISW has the largest phase velocity, while the mode-1 elevation ISW is the second, and the mode-2 ISW is the last. The location of the maximum amplitude from the characteristic function is consistent with the pycnocline as shown from floating frequency curve. The polarity of ISW is consistent with nonlinear parameter of alpha. Seismic data in global continental margins will provide more and more key evidence to increase our understanding of ISW evolution in the ocean.&lt;/p&gt;

scholarly journals Hatching Success Rather Than Temperature-Dependent Sex Determination as the Main Driver of Olive Ridley (Lepidochelys olivacea) Nesting Activity in the Pacific Coast of Central America

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3168
Author(s):  
Alejandra Morales Mérida ◽  
Aude Helier ◽  
Adriana A. Cortés-Gómez ◽  
Marc Girondot
Keyword(s):  
Solar Radiation ◽  
Central America ◽  
Pacific Coast ◽  
Hatching Success ◽  
Temperature Dependent ◽  
Lepidochelys Olivacea ◽  
Marine Turtles ◽  
The Pacific ◽  
Main Driver ◽  
Nesting Activity

In marine turtles, sex is determined during a precise period during incubation: males are produced at lower temperatures and females at higher temperatures, a phenomenon called temperature-dependent sex determination. Nest temperature depends on many factors, including solar radiation. Albedo is the measure of the proportion of reflected solar radiation, and in terms of sand color, black sand absorbs the most energy, while white sand reflects more solar radiation. Based on this observation, darker sand beaches with higher temperatures should produce more females. As marine turtles show a high degree of philopatry, including natal homing, dark beaches should also produce more female hatchlings that return to nest when mature. When sand color is heterogeneous in a region, we hypothesize that darker beaches would have the most nests. Nevertheless, the high incubation temperature on beaches with a low albedo may result in low hatching success. Using Google Earth images and the SWOT database of nesting olive ridleys (Lepidochelys olivacea) in the Pacific coast of Mexico and Central America, we modeled sand color and nesting activity to test the hypothesis that darker beaches host larger concentrations of females because of feminization on darker beaches and female philopatry. We found the opposite result: the lower hatching success at beaches with a lower albedo could be the main driver of nesting activity heterogeneity for olive ridleys in Central America.

scholarly journals Dispersion to the Tropics of the Spiraea Aphid, Aphis spiraecola Patch

1969 ◽  
Vol 39 (1) ◽  
pp. 32-40
Author(s):  
George N. Wolcott
Keyword(s):  
United States ◽  
Puerto Rico ◽  
Central America ◽  
Pacific Coast ◽  
Virus Disease ◽  
Aphis Spiraecola ◽  
The Pacific ◽  
Northern United States ◽  
The Tropics ◽  
Young Growth

The spiraea aphid, Aphis spiraecola Patch, which previous to 1924 was known only on species of Spiraea in the northern United States, in that year appeared in mass infestations on citrus trees in Florida and Cuba, causing enormous damage by distorting and resetting the young growth. By 1926 it had spread to Puerto Rico, attacking not only various endemic trees and plants, but being implicated in the transmission of a new virus disease of papaya. By 1928, it was reported on citrus from Honduras in Central America, and it has since dispersed to Costa Rica, and on a great variety of hosts to California, Oregon, and Washington on the Pacific Coast.

Cimaria vargasi n. gen, n. sp. (Gastropoda: Pyramidellidae: Odostomiinae) from the Pacific Coast of Costa Rica, Central America

Zootaxa ◽  
2012 ◽  
Vol 3178 (1) ◽  
pp. 63
Author(s):  
TORE HØISÆTER
Keyword(s):  
Costa Rica ◽  
Central America ◽  
Pacific Coast ◽  
Biogeographic Province ◽  
The Pacific ◽  
The Family

The Panamic biogeographic province has long been thought to harbour a rich pyramidellid fauna. In the compilation of Keen (1971) the family is second only to the Turridae in being the most speciose gastropod family in the region, and no less than 350 species are listed. However a number of these have later been recognized to be synonyms, and in the update of the compilation by Skoglund (2002) the number of pyramidellids was reduced to 258.

scholarly journals Generation of Internal Solitary Waves by Lateral Circulation in a Stratified Estuary

2017 ◽  
Vol 47 (7) ◽  
pp. 1789-1797 ◽  
Author(s):  
Xiaohui Xie ◽  
Ming Li ◽  
Malcolm Scully ◽  
William C. Boicourt
Keyword(s):  
Solitary Waves ◽  
Tidal Flow ◽  
Tidal Currents ◽  
Internal Solitary Waves ◽  
Deep Channel ◽  
Mode 2 ◽  
Lee Wave ◽  
Salinity Data ◽  
Lateral Circulation ◽  
Stratified Estuary

AbstractInternal solitary waves are commonly observed in the coastal ocean where they are known to contribute to mass transport and turbulent mixing. While these waves are often generated by cross-isobath barotropic tidal currents, novel observations are presented suggesting that internal solitary waves result from along-isobath tidal flows over channel-shoal bathymetry. Mooring and ship-based velocity, temperature, and salinity data were collected over a cross-channel section in a stratified estuary. The data show that Ekman forcing on along-channel tidal currents drives lateral circulation, which interacts with the stratified water over the deep channel to generate a supercritical mode-2 internal lee wave. This lee wave propagates onto the shallow shoal and evolves into a group of internal solitary waves of elevation due to nonlinear steepening. These observations highlight the potential importance of three-dimensionality on the conversion of tidal flow to internal waves in the rotating ocean.

A new genus and species of polyclad flatworm found in the mantle cavities of gastropod molluscs in the high-intertidal zone of the Pacific coast of Central America

2007 ◽  
Vol 87 (2) ◽  
pp. 429-434 ◽  
Author(s):  
Anno Faubel ◽  
Ronald Sluys ◽  
David G. Reid
Keyword(s):  
Central America ◽  
Intertidal Zone ◽  
New Genus ◽  
Pacific Coast ◽  
New Genus And Species ◽  
Diagnostic Characters ◽  
The Pacific ◽  
Upper Eulittoral ◽  
High Intertidal Zone ◽  
Commensal Relationship

A commensal relationship is described between the polyclad flatworm Paraprostatum echinolittorinae Faubel & Sluys gen. et sp. nov. and gastropod molluscs living on the Pacific coast of central America. Although the worms are relatively large in comparison with their hosts, the latter sustained no apparent damage. Considering the fact that the molluscs live in the upper eulittoral zone and littoral fringe of the shore, it is unlikely that the polyclads could survive for long outside the hosts. Diagnostic characters for the new genus and species are a long penial stylet joined to the proximal vesicle and absence of Lang's vesicle. It is pointed out that Aprostatum clippertoni Bock, 1913 and A. longipenis (Kato, 1943) have been incorrectly transferred to the genus Euplana Girard, 1893 and that Discoplana malagensis Doignon, Artois & Deheyn, 2003 should be transferred to the genus Ilyella Faubel, 1983.

scholarly journals Assessment of tsunami hazards for the Central American Pacific coast from southern Mexico to northern Peru

2014 ◽  
Vol 14 (7) ◽  
pp. 1889-1903 ◽  
Author(s):  
B. Brizuela ◽  
A. Armigliato ◽  
S. Tinti
Keyword(s):  
Central America ◽  
Pacific Coast ◽  
Probabilistic Approach ◽  
Central American ◽  
Southern Mexico ◽  
Extended Region ◽  
The Pacific ◽  
Northern Peru ◽  
Run Up ◽  
Tsunami Run Up

Abstract. Central America (CA), from Guatemala to Panama, has been struck by at least 52 tsunamis between 1539 and 2013, and in the extended region from Mexico to northern Peru (denoted as ECA, Extended Central America in this paper) the number of recorded tsunamis in the same time span is more than 100, most of which were triggered by earthquakes located in the Middle American Trench that runs parallel to the Pacific coast. The most severe event in the catalogue is the tsunami that occurred on 2 September 1992 off Nicaragua, with run-up measured in the range of 5–10 m in several places along the Nicaraguan coast. The aim of this paper is to assess the tsunami hazard on the Pacific coast of this extended region, and to this purpose a hybrid probabilistic-deterministic analysis is performed, that is adequate for tsunamis generated by earthquakes. More specifically, the probabilistic approach is used to compute the Gutenberg–Richter coefficients of the main seismic tsunamigenic zones of the area and to estimate the annual rate of occurrence of tsunamigenic earthquakes and their corresponding return period. The output of the probabilistic part of the method is taken as input by the deterministic part, which is applied to calculate the tsunami run-up distribution along the coast.

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