Characteristics of upper heated oceanic layer from satellite observations

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1979.Microfiche copy available in Archives and Science.Bibliography : leaves 81-83.by Affonso da Silveira Mascarenhas, Jr.M.S

Wave induced mixing in the ocean

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Meteorology and Physical Oceanography, 1983.Microfiche copy available in Archives and Science.Bibliography: leaves 154-156.by Affonso da Silveira Mascarenhas, Jr.Ph.D

Effect of coastal-trapped waves and wind on currents and transport in the Gulf of California

The article of record as published may be located at http://dx.doi.org/10.1002/2013JC009538Subsurface pressure (SsP) observations from stations inside and outside of the Gulf of California (GC) are used to analyze the relationship between low-frequency currents, temperature, and transport inside the GC and intraseasonal coastal-trapped waves (CTWs), which propagate poleward along the coast toward the GC. Correlation functions and coherences of SsP stations were consistent with intraseasonal CTWs splitting in two at the mouth of the gulf: one part enters the gulf, propagates around the gulf, and eventually, toward the mouth, and another part that appears to ‘‘jump’’ the mouth of the gulf and travels poleward along the west coast of the peninsula. The correlation and coherence estimates of SsP at Manzanillo with currents showed that downwelling CTWs generated along-gulf current anomalies toward the head of the gulf at the mainland shelf of the mouth, whereas at Ballenas Channel sill (San Lorenzo sill) these waves generated current anomalies toward the mouth near the surface (bottom). At the San Lorenzo (SL) sill, downwelling CTWs increased the near-bottom ( 400 m) temperature and reduced the bottom transport of deep, fresher, and colder water that flows toward the head of the gulf. Cross-Calibrated Multiplatform winds were used to investigate their relationship with currents. The first empirical orthogonal function of the along-gulf wind stress showed that wind blowing toward the head of the gulf generated a reduction of bottom transport toward the head of the gulf through the SL sill, and intensified surface geostrophic current fluctuations toward the head of the gulf. There was also significant correlation between inflow bottom transport and outflow surface geostrophic velocities averaged across the gulf, consistent with the exchange pattern for the Northern Gulf.This work was funded by CONACyT through grants G33464-T, 38797-T, C01-25343, ESE-203401, and through a scholarship to M. O. Guti errez

Seasonal variation of the temperature and salinity at the entrance to the Gulf of California, Mexico

The article of record as published may be found at http://dx.doi.org/10.7773/cm.v26i4.621Se describe la variabilidad estacional en la entrada al Golfo de California utilizando datos de CTD en una sección a través de la entrada al golfo, la cual fue ocupada en ocho ocasiones entre 1992 y 1998. Se encontró que la variabilidad decrece rápidamente debajo de los 100 dbar; las desviaciones estándar mayores que 0.5ºC y 0.05 para temperatura y salinidad, respectivamente, fueron confinadas a la capa superior de 150 dbar. El campo medio de salinidad fue asimétrico, con aguas de menor salinidad (S 34.8) arriba de 50 dbar y entre 100 y 150 dbar cerca de Baja California. En la capa superior de 50 dbar se observó una termoclina estacional sobre la cual las temperaturas superficiales cambiaron de 21ºC en febrero a 31ºC en agosto. Debajo de los 100 dbar, la temperatura a una presión dada fue típicamente más fría en el centro de la sección, indicando flujo ciclónico (flujo de entrada al golfo cerca de Sinaloa y de salida del golfo cerca de Baja California). El enfriamiento subsuperficial en la mitad de la sección del golfo (flujo ciclónico) fue más fuerte durante el invierno y la primavera, época cuando el intercambio de calor entre el golfo y el Océano Pacífico es mayor. No se observó el calentamiento subsuperficial en la parte media de la sección que corresponde a un flujo anticiclónico. La distribución temporal y espacial de las masas de agua de mayor salinidad sugieren que los intercambios de calor se dan por la alternancia de flujos de entrada y salida de masas de agua de mayor temperatura (superficial) y menor temperatura (subsuperficial). Durante el evento de El Niño 1997–1998 se observó un hundimiento de 50 dbar en la termoclina en noviembre de 1997, así como una disminución de 0.1 a 0.2 de la salinidad de las aguas arriba de la termoclina.Seasonal variability at the entrance to the Gulf of California is described using high resolution CTD data from a section across the entrance to the gulf that was occupied eight times between 1992 and 1998. Variability decreased rapidly below 100 dbar, so that standard deviations exceeding 0.5ºC and 0.05 for temperature and salinity, respectively, were confined to the upper 150 dbar. The mean salinity field wasasymmetric, with fresher waters (S < 34.6) between 25 and 75 dbar next to Sinaloa and saltier waters (S > 34.8) above 50 dbar and between 100 and 150 dbar near Baja California. A seasonal thermocline developed in the upper 50 dbar, increasing from 21ºC in February surface temperatures to 31ºC in August. Below 100 dbar, temperature at a given pressure was typically colder in the center of the section, indicating cyclonic flow (flow into the gulf next to Sinaloa and out of the gulf next to Baja California). The subsurface mid-gulf cooling (cyclonic flow) was strongest during winter and spring when the exchange of heat between the gulf and the Pacific Ocean is large. Subsurface mid-gulf heating (corresponding to anticyclonic flow) was not observed. Temporal and spatial distribution of saline water masses suggests that heat exchanges take place by alternating the inflow and outflow of warm (surface) and cold (subsurface) water masses. The 1997–1998 El Niño resulted in a 50 dbar deepening of the thermocline in November 1997, as well as a freshening of 0.1 to 0.2 of waters above the thermocline.CONACYTUABCOceanographer of the Navy (US)Naval Postgraduate SchoolSecretaría de MarinaUNAM (Mexico)26653-T4271P-T9601400940151076-T920

Properties of an upper ocean front associated with water mass boundaries at the entrance to the Gulf of California, November 2004

The article of record as published may be located at http://dx.doi.org/10.1016/j.dsr2.2014.06.002iThe structure of an upper ocean front at the entrance to the Gulf of California is described. The front occurred in a region of strong cyclonic shear between fresher Pacific waters, which flowed into the Gulf along Sinaloa, and salty Gulf of California waters, which flowed out of the Gulf along Baja California. Observations included two high -resolution hydrographic sections across the entrance to the Gulf. One section used a towed CTD that profiled from near surface to 125 m

Geostrophic circulation between the Costa Rica Dome and Central America

The geostrophic circulation between the Costa Rica Dome and Central America is described from CTD observations collected in two surveys: (a) The Wet Cruise in September–October 1993, and the Jet Cruise in February–March 1994. Poleward coastal flow was present on both occasions, but the transition from flow around the dome to the poleward Costa Rica Coastal Current flow was quite tortuous because of the presence of mesoscale eddies. In particular, a warm anticyclonic eddy was found off the Gulf of Fonseca during both cruises, at an almost identical position and with similar dimensions (150 m deep, 250 km in diameter) and surface speed (0.5 m s 1 ). In the Gulf of Panama, poleward flow was also observed, weaker in February–March 1994 than in September–October 1993, when it penetrated to 600 m depth and transported 8.5 Sv. In September–October 1993, the current between the dome and the coast was mostly 100 m deep and weak ( 0.15 m s 1 ), although in its southern side it was deeper ( 450 m) and faster at 0.3 m s 1 . The poleward transport between the dome and the coast was 7 Sv. In February–March 1994 the Costa Rica Dome was a closed ring adjacent to the continental shelf, 500 km in diameter, at least 400 m deep, had geostrophic surface speeds 0.25 m s 1 , and subsurface maximum speed (0.15–0.20 m s 1 ) at 180 m depth; the associated uplift of the isotherms was 150 m. The flow in the south part of the dome splits into two branches, the weakest one going around the dome and the strongest one continuing east and turning south before reaching the Gulf of Panama. r 2008 Elsevier Ltd. All rights reserved.La circulación geostrófica entre el Domo de Costa Rica y América Central se describe a partir de las observaciones de CTD recopiladas en dos estudios: (a) The Wet Cruise en septiembre-octubre de 1993 y Jet Cruise en febrero-marzo de 1994. El flujo costero hacia el polo estuvo presente en ambos. ocasiones, pero la transición del flujo alrededor del domo al flujo hacia el polo de la Corriente Costera de Costa Rica fue bastante tortuosa debido a la presencia de remolinos de mesoescala. En particular, se encontró un remolino anticiclónico cálido frente al Golfo de Fonseca durante ambos cruceros, en una posición casi idéntica y con dimensiones similares (150 m de profundidad, 250 km de diámetro) y velocidad superficial (0,5 m s 1 ). En el Golfo de Panamá también se observó flujo hacia el polo, más débil en febrero-marzo de 1994 que en septiembre-octubre de 1993, cuando penetró a 600 m de profundidad y transportó 8,5 Sv. En septiembre-octubre de 1993, la corriente entre el domo y la costa era mayormente de 100 m de profundidad y débil (0,15 m s 1 ), aunque en su lado sur era más profunda (450 m) y más rápida a 0,3 m s 1 . El transporte hacia el polo entre el domo y la costa fue de 7 Sv. En febrero-marzo de 1994, el Domo de Costa Rica era un anillo cerrado adyacente a la plataforma continental, de 500 km de diámetro, al menos 400 m de profundidad, tenía velocidades geostróficas en la superficie de 0,25 m s 1 y una velocidad máxima en el subsuelo (0,15–0,20 m s 1 ) en 180 m de profundidad; la elevación asociada de las isotermas fue de 150 m. El flujo en la parte sur del domo se divide en dos ramas, la más débil gira alrededor del domo y la más fuerte continúa hacia el este y gira hacia el sur antes de llegar al Golfo de Panamá. r 2008 Elsevier Ltd. Todos los derechos reservados.Universidad Nacional, Costa RicaDepartamento de Físic