Thermohaline structure and geostrophic flow in the gulf of California, during 1992

Cruz, Adolfo Molina; Gómez, Mauricio Avella; Barajas, M.E Fernandez

doi:10.7773/cm.v20i2.958

Cited by 20 publications

(14 citation statements)

References 4 publications

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“…The data of Fernández‐Barajas et al . [] from a single line of stations along the longitudinal axis of the SGC during February 1992 showed geostrophic velocities of alternating sign reaching ~1000 m, suggesting the presence of eddies similar to those reported here. However, their cyclonic eddy at Pescadero basin had a radius of ~90–100 km, while the anticyclonic eddy between Carmen and Farallón basins was ~85 km in radius; both estimates are much larger than ours.…”

Section: Discussionsupporting

confidence: 74%

“…The structure of the Southern Gulf of California mesoscale eddies is described here for the first time based on detailed direct observations of currents and hydrographic properties, made in August 2004. This is a much more thorough description than those made previously from direct hydrographic observation [ Fernández‐Barajas et al ., ; Figueroa et al ., ], which did not have such detailed sampling. Four eddies were sampled, two anticyclones and two cyclones, arranged with alternating sense of rotation.…”

Section: Discussionmentioning

confidence: 99%

“…The only later hydrographic evidence of eddies in the SGC (by Fernández‐Barajas et al . [] from February 1992 and by Figueroa et al . [] from March 1984) suggest a series of geostrophic eddies, 400–500 m deep, with alternating sense of rotation along the SGC; however, their stations were very wide apart or were from single along‐gulf lines of stations, so that details were missing or no information was provided on the lateral structure.…”

Section: Introductionmentioning

confidence: 99%

“…[3] The oldest direct observations of a mesoscale eddy in the Southern Gulf of California (SGC) (Figure 1) were made in August 1978 [Emilsson and Alatorre, 1997], using surface drifters, a lowered Aanderaa current meter, and a few conductivity-temperature-depth (CTD) casts; a cyclonic eddy of~50 km radius and~70 m depth was found over Farallón basin (see basin names in Figure 1). The only later hydrographic evidence of eddies in the SGC (by Fernández- Barajas et al [1994] from February 1992 and by Figueroa et al [2003] from March 1984) suggest a series of geostrophic eddies, 400-500 m deep, with alternating sense of rotation along the SGC; however, their stations were very wide apart or were from single along-gulf lines of stations, so that details were missing or no information was provided on the lateral structure.…”

Section: Introductionmentioning

confidence: 99%

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Mesoscale eddies in the southern Gulf of California during summer: Characteristics and interaction with the wind stress

et al. 2013

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[1] The hydrodynamic characteristics of mesoscale eddies of the southern Gulf of California are described from observations made in August 2004. Vertical profiles tõ 1000 m were made with a conductivity-temperature-depth (CTD) probe with dissolved oxygen and fluorescence sensors, and a lowered acoustic Doppler profiler. The four sampled eddies were aligned along the Gulf axis and had alternating sense of rotation. The Okubo-Weiss parameter was used to calculate the eddy core radii, and it also revealed that the current field of almost all the sampled area was eddy dominated. The mean radii of the eddy cores varied between 32 and 36 km. Maximum surface velocities were 0.4-0.5 m/s. The anticyclonic eddies were 500-700 m deep, while the cyclones were 450-500 m deep. The depression of the isolines associated with the anticyclonic eddies was~100 m at depths between 200 and 400 m; however, the thermocline/pycnocline, which spanned from~20 to 75 m, was domed by~10 m. The cyclonic eddies lifted the isolines by~70 m at depths above 500 m, but the isolines were flat above~60 m. This suggests that different dynamics operate in the layer above the strong and shallow pycnocline. In particular, the wind stress curl can affect circulation and pycnocline topography and, therefore, the patterns that appear in chlorophyll satellite images. In our case, the eddies were detectable in those images because of the chlorophyll-enhanced streamers along their edges and, for anticyclones, probably because the chlorophyll maximum found at 40-50 m depth was domed following the pycnocline.Citation: Lavı´n, M. F., R. Castro, E. Beier, and V. M. Godı´nez (2013), Mesoscale eddies in the southern Gulf of California during summer: Characteristics and interaction with the wind stress,

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Section: Discussionsupporting

confidence: 74%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mesoscale eddies in the southern Gulf of California during summer: Characteristics and interaction with the wind stress

et al. 2013

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“…A bathymetric sill above 250 m depth (Fig. 1(B)) (Nava‐Sánchez, 1997) inhibits incursion of Pacific Intermediate Water (PID) and Pacific Deep Water (PDW), which are present in the southern and central Gulf of California (Fernández‐Barajas et al , 1994; Monreal‐Gómez et al , 2001). The ESW (predominantly above the thermocline) and the SSW enter the Gulf of California from the Pacific Ocean.…”

Section: Alfonso Basin Gulf Of Californiamentioning

confidence: 99%

Holocene laminated sediments from the southern Gulf of California: geochemical, mineral magnetic and microfossil study

Pérez‐Cruz

Urrutia‐Fucugauchi

2010

J Quaternary Science

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Pérez-Cruz, L. and Urrutia-Fucugauchi, J. 2010. Holocene laminated sediments from the southern Gulf of California: geochemical, mineral magnetic and microfossil study.ABSTRACT: Geochemical, magnetic mineral analyses and microfossils (radiolarians) are used to characterise a Holocene laminated sequence from the Alfonso Basin, northern Bay of La Paz, southern Gulf of California. In most cases, dark and light laminae show similar bulk chemical compositions and magnetic mineral properties. However, dark laminae contain relatively more terrigenous elements (Al, Si, Fe, K and Mg) supporting a pluvial origin related to the volcanic siliceous tuffs around the Bay of La Paz. In light laminae, calcium content is higher, representing biogenic input. The magnetic signal is dominated by low coercivity, fine-grained low-titanium titanomagnetites and magnetite. Hysteresis ratio parameters in domain state plots show that samples fall in the pseudo-single domain field, indicating mixtures of single-and multi-domain particles. Variations in hysteresis saturation magnetisation parameters for dark and light laminae reflect changes in relative mineral concentration. Results indicate a dominant volcanic source for magnetic minerals into the basin, associated with variable pluvial and/or aeolian transport. Low radiolarian abundance in dark laminae seems to be associated with larger penetration and longer residence time of oligotrophic subtropical waters into the bay that occurred during El Niñ o-Southern Oscillation (ENSO) events. Light laminae are the result of episodic pulses of high productivity. We suggest that dark/light laminae result from oceanographic and climatic cyclic processes, with main terrigenous input variation possibly associated with ENSO forcing of pluvial influx, and/or latitudinal migration of the Intertropical Convergence Zone. The laminated sequence of the Alfonso Basin formed a non-annual depositional system, in contrast to the varved sediments characteristic of the central Gulf of California basins.

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Decadal to centennial fluctuations in the intensity of the eastern tropical North Pacific oxygen minimum zone during the last 1200 years

et al. 2016

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Oxygen minimum zones (OMZs), located below highly productive marine regions, are sites of microbially mediated denitrification and biogeochemical cycling that have global significance. The intensity of OMZs fluctuates naturally; however, the degree of these fluctuations and a comprehensive understanding of the factors that drive these fluctuations on decadal to centennial time scales is lacking. Our high-resolution (near-annual) record of δ 15 N sed from laminated sediments at the Pescadero Slope in the Gulf of California (eastern tropical North Pacific) fluctuates between maximum values of 10.5‰ and minimum values of 8.0‰ over the past 1200 years. An analysis of the relationship between δ 15 NO 3 À and [O 2 ] in the water column suggests that the observed range of δ 15 N sed values is equivalent to an approximately 8 μM fluctuation in O 2 content and that these changes can occur in less than 25 years. Our findings show that the OMZ typically intensifies quickly and contracts gradually; the average rate of OMZ intensification (À0.24 μM O 2 /yr) is twice as fast as the rate of OMZ reoxygenation. Spectral analyses of the δ 15 N sed record and Br/Cl counts, with the latter are used as a proxy for organic carbon preservation, suggest that the Pacific Decadal Oscillation and the Suess (deVries) solar cycle (solar irradiance) may influence the intensity of the OMZ and carbon production/export during the late Holocene. Coherence between δ 15 N sed and weight percent organic carbon also suggests that similar mechanisms influence both OMZ fluctuations and variation in organic carbon production/export.

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Thermohaline structure and geostrophic flow in the gulf of California, during 1992

Cited by 20 publications

References 4 publications

Mesoscale eddies in the southern Gulf of California during summer: Characteristics and interaction with the wind stress

Mesoscale eddies in the southern Gulf of California during summer: Characteristics and interaction with the wind stress

Holocene laminated sediments from the southern Gulf of California: geochemical, mineral magnetic and microfossil study

Decadal to centennial fluctuations in the intensity of the eastern tropical North Pacific oxygen minimum zone during the last 1200 years

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