scholarly journals Effect of Caribbean Water Incursion into the Gulf of Mexico derived from Absolute Dynamic Topography, Satellite Data, and Remotely – sensed Chlorophyll-<i>a</i>

2019 ◽  
Author(s):  
Juan Antonio Delgado ◽  
Joël Sudre ◽  
Sorayda Tanahara ◽  
Ivonne Montes ◽  
José Martin Hernandez-Ayon ◽  
...  
Keyword(s):  
Satellite Data ◽  
Winter Period ◽  
Time Interval ◽  
Loop Current ◽  
Dynamic Topography ◽  
Physical Processes ◽  
Surface Layers ◽  
Chl A ◽  
Mean Differences ◽  
Oceanic Currents

Abstract. The dynamics of the Loop Current (LC) and the detached Loop Current eddies (LCE’s) dominate the Gulf of Mexico's (GoM) surface layers' circulation transporting Caribbean water (CW) into the GoM.  In this work, 25-years (1993–2017) of daily satellite data are used to investigate the variability of these physical processes and their effect on chlorophyll-a (Chl-a) concentrations from 1998–2017 including temporal changes, mean differences, and regional concentration tendencies. Physical variables analyzed are absolute dynamic topography (ADT), oceanic currents, and wind stress. From the ADT and oceanic current monthly climatologies, it is shown that there is an annual intrusion of the CW with an inward incursion that starts in spring, peaks in the summer (reaching to 26.58˚N and 88.32˚W) and then retreats in winter. Minimum surface Chl-a concentrations (<0.08 mg m−3) are found during the summer-autumn period inside the region of maximum incursion of the CW; the opposite is observed during the winter period when the Chl-a concentrations were at a maximum, e.g., >0.14 mg m−3. The three-year running averages of ADT 40-cm isoline reproduce qualitatively the climatological pattern of 25 years showing that before 2002 the CW was less intrusive. This suggests that from 2003 onward, larger volumes of oligotrophic waters from Caribbean Sea have invaded the western GoM and reduced mean surface Chl-a concentrations. A direct comparison between the 1998–2002 and 2009–2014 periods indicates that, in the latter time interval, Chl-a concentration over waters deeper than 250 m has decreased significantly.

scholarly journals Effect of Caribbean Water incursion into the Gulf of Mexico derived from absolute dynamic topography, satellite data, and remotely sensed chlorophyll <i>a</i>

Ocean Science ◽  
2019 ◽  
Vol 15 (6) ◽  
pp. 1561-1578 ◽  
Author(s):  
Juan Antonio Delgado ◽  
Joël Sudre ◽  
Sorayda Tanahara ◽  
Ivonne Montes ◽  
José Martín Hernández-Ayón ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Satellite Data ◽  
Winter Period ◽  
Time Interval ◽  
Loop Current ◽  
Dynamic Topography ◽  
Chl A ◽  
Surface Circulation ◽  
Mean Differences ◽  
Oceanic Currents

Abstract. The dynamics of the Loop Current (LC) and the detached Loop Current eddies (LCEs) dominate the surface circulation of the Gulf of Mexico (GoM) and transport Caribbean Water (CW) into the gulf. In this work, 25 years (1993–2017) of daily satellite data are used to investigate the variability of these physical processes and their effect on chlorophyll a (Chl a) concentrations from 1998 to 2017, including temporal changes, mean differences, and regional concentration tendencies. The physical variables analyzed are absolute dynamic topography (ADT) and oceanic currents. From the ADT and oceanic current monthly climatologies, it is shown that there is an annual intrusion of CW with an inward incursion that starts in spring, peaks in the summer, reaches to 28∘ N and 90.45∘ W, and then retreats in winter to approximately 26.5 ∘ N and 88.3 ∘ W. Minimum surface Chl a concentrations (< 0.08 mg m−3) are found during the summer–autumn period inside the region of maximum incursion of CW; the opposite is observed during the winter period when Chl a concentrations were at a maximum, e.g., > 0.14 mg m−3. The 3-year running averages of the ADT 40 cm isoline qualitatively reproduce the climatological pattern of 25 years showing that before 2002 CW was less intrusive. This suggests that from 2003 onward, larger volumes of oligotrophic waters from the Caribbean Sea have invaded the western GoM and reduced mean surface Chl a concentrations. A direct comparison between the 1998–2002 and 2009–2014 periods indicates that in the latter time interval, the Chl a concentration above waters deeper than 250 m has decreased significantly.

Longitudinal and Gender Measurement Invariance of the Gratitude Questionnaire in Chinese Adolescents

2021 ◽  
pp. 003329412110360
Author(s):  
Qingsong Tan ◽  
Jilin Zou ◽  
Feng Kong
Keyword(s):  
Measurement Invariance ◽  
Time Interval ◽  
Longitudinal Measurement Invariance ◽  
Multiple Group ◽  
Longitudinal Measurement ◽  
Confirmatory Factor ◽  
Adolescent Sample ◽  
Good Internal Consistency ◽  
And Gender ◽  
Mean Differences

The 5-item Gratitude Questionnaire (GQ-5) is one of the most commonly used instruments to measure dispositional gratitude in adolescents. The purpose of this study was to verify the longitudinal measurement invariance (LMI) and gender measurement invariance (GMI) of the GQ-5 that was administered to an adolescent sample twice over the course of 18 months ( N = 669). Single-group confirmatory factor analysis (CFA) was adopted to examine the LMI and multiple-group CFA was conducted to assess the GMI. The results showed that the GQ-5 had strong invariance (i.e., equality of factor patterns, loadings, and intercepts) across time and gender. Validation of latent factor mean differences showed that females had higher gratitude scores than males. In addition, the GQ-5 exhibited good internal consistency indices across time and a moderate stability coefficient was also found across an 18-month time interval in adolescents. In summary, our study showed that LMI and GMI of the GQ-5 are satisfactory and the GQ-5 is a reliable instrument for measuring gratitude in adolescents.

scholarly journals Spatiotemporal Variability of Surface Phytoplankton Carbon and Carbon-to-Chlorophyll a Ratio in the South China Sea Based on Satellite Data

2020 ◽  
Vol 13 (1) ◽  
pp. 30
Author(s):  
Wenlong Xu ◽  
Guifen Wang ◽  
Long Jiang ◽  
Xuhua Cheng ◽  
Wen Zhou ◽  
...  
Keyword(s):  
South China Sea ◽  
Chlorophyll A ◽  
South China ◽  
Satellite Data ◽  
Phytoplankton Biomass ◽  
The South China Sea ◽  
Spatiotemporal Variability ◽  
The South ◽  
Chl A ◽  
China Sea

The spatiotemporal variability of phytoplankton biomass has been widely studied because of its importance in biogeochemical cycles. Chlorophyll a (Chl-a)—an essential pigment present in photoautotrophic organisms—is widely used as an indicator for oceanic phytoplankton biomass because it could be easily measured with calibrated optical sensors. However, the intracellular Chl-a content varies with light, nutrient levels, and temperature and could misrepresent phytoplankton biomass. In this study, we estimated the concentration of phytoplankton carbon—a more suitable indicator for phytoplankton biomass—using a regionally adjusted bio-optical algorithm with satellite data in the South China Sea (SCS). Phytoplankton carbon and the carbon-to-Chl-a ratio (θ) exhibited considerable variability spatially and seasonally. Generally, phytoplankton carbon in the northern SCS was higher than that in the western and central parts. The regional monthly mean phytoplankton carbon in the northern SCS showed a prominent peak during December and January. A similar pattern was shown in the central part of SCS, but its peak was weaker. Besides the winter peak, the western part of SCS had a secondary maximum of phytoplankton carbon during summer. θ exhibited significant seasonal variability in the northern SCS, but a relatively weak seasonal change in the western and central parts. θ had a peak in September and a trough in January in the northern and central parts of SCS, whereas in the western SCS the minimum and maximum θ was found in August and during October–April of the following year, respectively. Overall, θ ranged from 26.06 to 123.99 in the SCS, which implies that the carbon content could vary up to four times given a specific Chl-a value. The variations in θ were found to be related to changing phytoplankton community composition, as well as dynamic phytoplankton physiological activities in response to environmental influences; which also exhibit much spatial differences in the SCS. Our results imply that the spatiotemporal variability of θ should be considered, rather than simply used a single value when converting Chl-a to phytoplankton carbon biomass in the SCS, especially, when verifying the simulation results of biogeochemical models.

scholarly journals Influence of frontal cyclone evolution on the 2009 (Ekman) and 2010 (Franklin) Loop Current eddy detachment events

Ocean Science ◽  
2014 ◽  
Vol 10 (6) ◽  
pp. 947-965 ◽  
Author(s):  
Y. S. Androulidakis ◽  
V. H. Kourafalou ◽  
M. Le Hénaff
Keyword(s):  
Numerical Simulation ◽  
Gulf Of Mexico ◽  
Satellite Data ◽  
Potential Vorticity ◽  
In Situ Measurements ◽  
Loop Current ◽  
Positive Potential ◽  
Eastern Gulf Of Mexico ◽  
And Migration

Abstract. The anticyclonic Loop Current Eddy (LCE) shedding events are strongly associated with the evolution of Loop Current Frontal Eddies (LCFEs) over the eastern Gulf of Mexico (GoM). A numerical simulation, in tandem with in situ measurements and satellite data, was used to investigate the Loop Current (LC) evolution and the surrounding LCFE formation, structure, growth and migration during the Eddy Ekman and Eddy Franklin shedding events in the summers of 2009 and 2010, respectively. During both events, northern GoM LCFEs appeared vertically coherent to at least 1500 m in temperature observations. They propagated towards the base of the LC, where, together with the migration of Campeche Bank (southwest GoM shelf) eddies from south of the LC, contributed to its "necking-down". Growth of Campeche Bank LCFEs involved in Eddy Franklin was partially attributed to Campeche Bank waters following upwelling events. Slope processes associated with such upwelling included offshore exports of high positive potential vorticity that may trigger cyclone formation and growth. The advection and growth of LCFEs, originating from the northern and southern GoM, and their interaction with the LC over the LCE detachment area favor shedding conditions and may contribute to the final separation of the LCE.

scholarly journals A Review of the Morphology, Physical Processes and Deposits of Modern Straits

2021 ◽  
pp. SP523-2021-76
Author(s):  
Robert W. Dalrymple
Keyword(s):  
High Energy ◽  
Energy Conditions ◽  
Physical Processes ◽  
Content Type ◽  
Fluvial Deposits ◽  
Sediment Waves ◽  
Contourite Drifts ◽  
Supplementary Material ◽  
Maximum Flooding Surface ◽  
Oceanic Currents

AbstractThis study reviews the morphology, hydrodynamics and sedimentology of 33 modern straits, including examples from diverse tectonic and climatic settings. Strait morphology ranges from short, simple straits to long, tortuous passages many 100s of kilometers long; depths range from 10 m to >1 km. The morphological building block of strait sedimentation is a constriction flanked by open basins; a single strait can contain one or several of these. Currents accelerate through the constrictions and decelerate in the basins, leading to a spatial alternation of high- and low-energy conditions. Currents in a strait can be classified as either ‘persistent’ (oceanic currents or density-driven circulation) or ‘intermittent’ (tidally or meteorologically generated currents). Constrictions tend to be bedload partings, with the development of transport paths that diverge outward. Deposition occurs where the flow decelerates, generating paired subaqueous ‘constriction-related deltas’ that can be of unequal size. Cross-bedding predominates in high-energy settings; muddy sediment waves and contourite drifts are present in some straits. In shallow straits that were exposed during the sea-level lowstand, strait deposits typically occur near or at the maximum flooding surface, and can overlie estuarine and fluvial deposits. The most energetic deposits need not occur at the time of maximum inundation.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5746061

scholarly journals SPATIAL-TEMPORAL DISTRIBUTION OF CHLOROPHYLL-A IN SOUTHERN PART OF THE MAKASSAR STRAIT

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Wasir Samad Daming ◽  
Muhammad Anshar Amran ◽  
Amir Hamzah Muhiddin ◽  
Rahmadi Tambaru
Keyword(s):  
Chlorophyll A ◽  
Satellite Data ◽  
Chlorophyll Concentration ◽  
Temporal Distribution ◽  
Fishing Ground ◽  
Landsat 8 ◽  
Trade Winds ◽  
Chl A ◽  
June July ◽  
Potential Area

Surface chlorophyll-a (Chl-a) distribution have been analyzed with seasonal variation during southeast monsoon in southern part of Makassar Strait and Flores Sea. Satellite data of Landsat-8 is applied to this study to formulate the distribution of chlorophyll concentration during monsoonal wind period. The distribution of chlorophyll concentration was normally peaked condition in August during southeast monsoon. Satellite data showed that a slowdown in the rise of the distribution of chlorophyll in September with a lower concentration than normal is likely due to a weakening the strength of southeast trade winds during June – July – August 2016. Further analysis shows that the southern part of the Makassar strait is likely occurrence of upwelling characterized by increase in surface chlorophyll concentrations were identified as the potential area of fishing ground.

scholarly journals Recharge Impulse Spreading in Western Carpathian’s Mountainous Fissure–Karst Aquifer

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 763 ◽  
Author(s):  
Malík ◽  
Coplák ◽  
Kuvik ◽  
Švasta
Keyword(s):  
Water Temperature ◽  
Karst Aquifer ◽  
Large Body ◽  
Vertical Component ◽  
Groundwater Table ◽  
Time Shift ◽  
Winter Period ◽  
Time Interval ◽  
Spring Discharge ◽  
Groundwater Flux

: Foreseen construction of a highway tunnel in the northern part of the Veľká Fatra Mts. (Slovakia) triggered the need for extensive hydrogeological investigations. The projected tunnel axis would cut through a large body buildup of Middle Triassic carbonate rocks. Dolomites and limestones with fissure–karstic permeability are surrounded by less-permeable marls, so that all springs dewatering this uplifted plate of carbonates are found above the erosion base on its edges. Detailed, hourly-based discharge monitoring of all four major springs was performed during the spring and summer period of 2014. In the meantime, groundwater table observations in two boreholes, located in the center of the fissure–karst aquifer, were run in the same time interval. Based on air temperature and precipitation records, the 2013–2014 winter period was practically without snow cover. In the middle of March 2014, an intense rainfall event caused a sudden rise of the groundwater table in the TK-04 borehole located in the southern part of the carbonate plate. Spreading of this singular hydraulic impulse throughout the structure was differently registered at individual springs within the time shift span of 1.38 to 65.25 days. Groundwater level rise of 0.40 m in the TK-04 borehole was postponed in 5.33 days. The response time of spring discharge to sudden groundwater table rise within the structure occurred later at springs with a higher water temperature. Water temperature differences between individual springs were still within the 2.46 °C narrow interval (5.57–8.03 °C). The vertical component of groundwater flux should play an important role even in a relatively simple, plate-shaped mountainous karstic aquifer fully uplifted above the erosional base, as was the case of the investigated Kopa Mt. hydrogeological structure.

scholarly journals Discovery of β Cep pulsations in the eclipsing binary V453 Cygni

2020 ◽  
Vol 497 (1) ◽  
pp. L19-L23 ◽  
Author(s):  
John Southworth ◽  
D M Bowman ◽  
A Tkachenko ◽  
K Pavlovski
Keyword(s):  
Physical Properties ◽  
Satellite Data ◽  
Binary Stars ◽  
Mass Measurement ◽  
Physical Processes ◽  
Primary Star ◽  
Eclipsing Binary ◽  
Period Orbit ◽  
Orbital Frequency ◽  
Short Period

ABSTRACT V453 Cyg is an eclipsing binary containing 14 and 11 $\, {\rm M}_\odot$ stars in an eccentric short-period orbit. We have discovered β Cep-type pulsations in this system using Transiting Exoplanet Survey Satellite data. We identify seven significant pulsation frequencies, between 2.37 and 10.51 d−1, in the primary star. These include six frequencies that are separated by yet significantly offset from harmonics of the orbital frequency, indicating they are tidally perturbed modes. We have determined the physical properties of the system to high precision: V453 Cyg A is the first β Cep pulsator with a precise mass measurement. The system is a vital tracer of the physical processes that govern the evolution of massive single and binary stars.

scholarly journals Satellite-measured seasonal variations in primary production in the scallop-farming region of the Okhotsk Sea

2009 ◽  
Vol 66 (7) ◽  
pp. 1557-1569 ◽  
Author(s):  
M. A. Mustapha ◽  
S. Sei-Ichi ◽  
T. Lihan
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Seasonal Variations ◽  
Cold Water ◽  
Late Spring ◽  
Frontal Area ◽  
Okhotsk Sea ◽  
Physical Processes ◽  
Soya Warm Current ◽  
Chl A

Abstract Mustapha, M. A., Sei-Ichi, S., and Lihan, T. 2009. Satellite-measured seasonal variations in primary production in the scallop-farming region of the Okhotsk Sea. – ICES Journal of Marine Science, 66: 1557–1569. Seasonal variation in primary production after a retreat of the sea ice in the scallop-farming region along the Hokkaido coast of the Okhotsk Sea (1998–2004) was determined using satellite images. Annual variability in primary production was caused by variability in the physical processes associated with retreat of the sea ice, advection of the Sōya Warm Current (SWC), and intrusion of the East Sakhalin Current (ESC). Variability in primary production resulted in variability in the Chl a concentration, which was also demonstrated with an empirical orthogonal function (EOF) analysis. Enhancement of Chl a concentration in the frontal area in late spring was demonstrated by the second EOF mode of Chl a concentration (14.2% of variance), in parallel with the generation of a well-developed frontal area resulting from the advection of warm waters of the SWC along the coast in late spring, as indicated by the second EOF mode of sea surface temperature (SST; 1.8% of variance). Elevated Chl a concentration and the presence of cold water of the ESC in late autumn were also highlighted by the third EOF mode of Chl a concentration (9.0% of variance) and SST (1.5% of variance). Prolonged high primary production within the scallop-farming region after spring is supported by the development of a frontal area in summer and strengthening of the ESC in autumn.

Investigations of the Tasman Sea by satellite altimetry

1984 ◽  
Vol 35 (6) ◽  
pp. 619 ◽  
Author(s):  
R Coleman
Keyword(s):  
Spatial Distribution ◽  
Satellite Data ◽  
Satellite Altimetry ◽  
Sea Surface ◽  
Altimeter Data ◽  
Winter Period ◽  
East Australian Current ◽  
Tasman Sea ◽  
Topographic Influence ◽  
Surface Variability

Altimeter data obtained over a period of 3.6 years (from April 1975 to November 1978) and over the winter period July-September 1978 from the GEOS-3 and SEASAT satellites were used to study the spatial distribution of mesoscale sea-surface variability in the Tasman Sea. Satellite data generally agreed with existing hydrographic measurements. Patterns of higher sea-surface variability were shown to be associated with the East Australian Current and eddy areas. Though the Tasman Front is known to be present at certain times of the year, it is concluded that it is not a permanent feature across the Tasman Sea. Low variability levels in the mid-Tasman Sea are seemingly dictated by the Lord Howe Rise, thus suggesting some sort of topographic influence.

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