@article {Biescas2016,
	title = {{Synthetic Modeling for an Acoustic Exploration System for Physical Oceanography}},
	journal = {Journal of Atmospheric and Oceanic Technology},
	volume = {33},
	number = {1},
	year = {2016},
	pages = {191{\textendash}200},
	publisher = {American Meteorological Society},
	abstract = {AbstractMarine multichannel seismic (MCS) data, used to obtain structural reflection images of the earth?s subsurface, can also be used in physical oceanography exploration. This method provides vertical and lateral resolutions of O(10?100) m, covering the existing observational gap in oceanic exploration. All MCS data used so far in physical oceanography studies have been acquired using conventional seismic instrumentation originally designed for geological exploration. This work presents the proof of concept of an alternative MCS system that is better adapted to physical oceanography and has two goals: 1) to have an environmentally low-impact acoustic source to minimize any potential disturbance to marine life and 2) to be light and portable, thus being installed on midsize oceanographic vessels. The synthetic experiments simulate the main variables of the source, shooting, and streamer involved in the MCS technique. The proposed system utilizes a 5-s-long exponential chirp source of 208 dB relative to 1 ?Pa at 1 m with a frequency content of 20?100 Hz and a relatively short 500-m-long streamer with 100 channels. This study exemplifies through numerical simulations that the 5-s-long chirp source can reduce the peak of the pressure signal by 26 dB with respect to equivalent air gun?based sources by spreading the energy in time, greatly reducing the impact to marine life. Additionally, the proposed system could be transported and installed in midsize oceanographic vessels, opening new horizons in acoustic oceanography research.},
	issn = {0739-0572},
	doi = {10.1175/JTECH-D-15-0137.1},
	url = {http://dx.doi.org/10.1175/JTECH-D-15-0137.1},
	author = {Biescas, Berta and Ruddick, Barry and Kormann, Jean and Sallares, Valenti and Nedimovi{\'c}, Mladen R and Carniel, Sandro}
}
@article {Biescas2014,
	title = {{Recovery of temperature, salinity, and potential density from ocean reflectivity}},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {119},
	number = {5},
	year = {2014},
	pages = {3171{\textendash}3184},
	publisher = {Blackwell Publishing Ltd},
	abstract = {This work explores a method to recover temperature, salinity, and potential density of the ocean using acoustic reflectivity data and time and space coincident expendable bathythermographs (XBT). The acoustically derived (vertical frequency >10 Hz) and the XBT-derived (vertical frequency <10 Hz) impedances are summed in the time domain to form impedance profiles. Temperature (T) and salinity (S) are then calculated from impedance using the international thermodynamics equations of seawater (GSW TEOS-10) and an empirical T-S relation derived with neural networks; and finally potential density ($\rho$) is calculated from T and S. The main difference between this method and previous inversion works done from real multichannel seismic reflection (MCS) data recorded in the ocean, is that it inverts density and it does not consider this magnitude constant along the profile, either in vertical or lateral dimension. We successfully test this method on MCS data collected in the Gulf of Cadiz (NE Atlantic Ocean). T, S, and $\rho$ are inverted with accuracies of $δ$Tsd=0.1C, $δ$Ssd=0.09, and $δ$$\rho$sd=0.02kg/m 3. Inverted temperature anomalies reveal baroclinic thermohaline fronts with intrusions. The observations support a mix of thermohaline features created by both double-diffusive and isopycnal stirring mechanisms. Our results show that reflectivity is primarily caused by thermal gradients but acoustic reflectors are not isopycnal in all domains. Key Points Recovery of oceanic T, S, and potential density from acoustic reflectivity data Thermal anomalies observations at the Mediterranean tongue level Comparison between acoustic reflectors in the ocean and isopycnals {\textcopyright} 2014. American Geophysical Union. All Rights Reserved.},
	keywords = {low-frequency acoustic oceanography, ocean reflectivity, Seismic oceanography, thermohaline fronts, thermohaline intrusions},
	issn = {21699275},
	doi = {10.1002/2013JC009662},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-84902770570\&partnerID=tZOtx3y1},
	author = {Biescas, Berta and Ruddick, Barry R. and Nedimovic, Mladen R. and Sallares, Valenti and Bornstein, Guillermo and Mojica, Jhon F.}
}
@article {Biescas2010,
	title = {{Seismic imaging of staircase layers below the Mediterranean Undercurrent}},
	journal = {Deep Sea Research Part I: Oceanographic Research Papers},
	volume = {57},
	number = {10},
	year = {2010},
	month = {oct},
	pages = {1345{\textendash}1353},
	abstract = {Seismic images of staircase layers at the bottom of the Mediterranean Undercurrent with a lateral coherence up to 50. km and a horizontal resolution of \~{}10m are presented. The images show clearly the interaction between these staircase layers and other flow structures such as meddies, seamounts and internal waves. The staircase layers were imaged during two different surveys that used different sound sources. Comparison between seismic images and historical oceanographic observations illustrates the importance of using a seismic source adapted to the vertical scale of the oceanographic target to be imaged. Wavelengths larger than the size of the staircase structure distort the image in the vertical. For optimal imaging, deconvolution of the data is required. {\textcopyright} 2010 Elsevier Ltd.},
	keywords = {Boundary mixing, Gulf of Cadiz, Meddy, Mediterranean Undercurrent, Seismic oceanography, Thermohaline staircase layers},
	issn = {09670637},
	doi = {10.1016/j.dsr.2010.07.001},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-77956879722\&partnerID=tZOtx3y1},
	author = {Biescas, Berta and Armi, Larry and Sallares, Valenti and Gr{\'a}cia, Eul{\`a}lia}
}
@article {Kormann2010,
	title = {{Synthetic modelling of acoustical propagation applied to seismic oceanography experiments}},
	journal = {Geophysical Research Letters},
	volume = {37},
	number = {6},
	year = {2010},
	month = {mar},
	pages = {n/a{\textendash}n/a},
	abstract = {Recent work shows that multichannel seismic (MCS) systems provide detailed information on the oceans{\textquoteright} finestructure. The aim of this paper is to analyze if high order numerical algorithms are suitable to accurately model the extremely weak wavefield scattered by the oceans{\textquoteright} finestructures. For this purpose, we generate synthetic shot records along a coincident seismic and oceanographic profile acquired across a Mediterranean salt lens in the Gulf of Cadiz. We apply a 2D finite-difference time-domain propagation model, together with second-order Complex Frequency Shifted Perfectly Matched Layers at the numerical boundaries, using as reference a realistic sound speed map with the lateral resolution of the seismic data. We show that our numerical propagator creates an acoustical image of the ocean finestructures including the salt lens that reproduces with outstanding detail the real acquired one. Copyright {\textcopyright} 2010 by the American Geophysical Union.},
	issn = {00948276},
	doi = {10.1029/2009GL041763},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-77949835265\&partnerID=tZOtx3y1},
	author = {Kormann, Jean and Cobo, Pedro and Biescas, Berta and Sallares, Valenti and Papenberg, Cord and Recuero, Manuel and Carbonell, Ram{\'o}n}
}
@article {Kormann2009,
	title = {{Modelling Seismic Oceanography Experiments by Using First- and Second-Order Complex Frequency Shifted Perfectly Matched Layers}},
	journal = {Acta Acustica united with Acustica},
	volume = {95},
	number = {6},
	year = {2009},
	month = {nov},
	pages = {1104{\textendash}1111},
	abstract = {This work investigates the ability of modelling seismic oceanography experiments by using underwater acoustic propagation equations. Seismic oceanography tries to retrieve the fine structure of the ocean water masses by processing the acoustic waves reflected in the low-contrast interfaces of fronts, eddies, internal waves or thermohaline intrusions. Since the reflectivity of such interfaces is of order 10-3-10-4, the absorption capability of the numerical boundaries becomes crucial. Complex Frequency Shifted offers a better alternative to classical Perfectly Matched Layer formulation, but has not yet been extended to acoustic equations. Here, first- and second-order Complex Frequency Shifted Perfectly Matched Layers equations are proposed which can provide reflection coefficients of order 10-5. Therefore, a numerical Finite-Difference Time-Domain (FDTD) scheme combined with the proposed CFS-PML equations is able to model such experiments. {\textcopyright} S. Hirzel Verlag {\textperiodcentered} EAA.},
	issn = {16101928},
	doi = {10.3813/AAA.918242},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-77149123321\&partnerID=tZOtx3y1},
	author = {Kormann, Jean and Cobo, Pedro and Recuero, Manuel and Biescas, Berta and Sallares, Valenti}
}
@article {Biescas2007,
	title = {{Seismic attenuation of coda waves in the eastern region of Cuba}},
	journal = {Tectonophysics},
	volume = {429},
	number = {1-2},
	year = {2007},
	pages = {99{\textendash}109},
	publisher = {Elsevier},
	abstract = {11 pages, 8 figures, 2 tables},
	keywords = {coda wave, Cuba, quality factor Q, Seismic attenuation},
	issn = {00401951},
	doi = {10.1016/j.tecto.2006.09.013},
	url = {http://digital.csic.es/handle/10261/26812},
	author = {Biescas, Berta and Rivera, Zulima and Zapata, Jose Alejandro}
}
