Similarities and Contrasts in Time-Mean Striated Surface Tracers in Pacific Eastern Boundary Upwelling Systems: The Role of Ocean Currents in Their Generation

Eastern boundary upwelling systems feature strong zonal gradients of physical and biological properties between cool, productive coastal oceans and warm, oligotrophic subtropical gyres. Zonal currents and jets (striations) are therefore likely to contribute to the transport of water properties between coastal and open oceanic regions. For the first time, multi-sensor satellite data are used to characterize the time-mean signatures of striations in sea surface temperature (SST), salinity (SSS), and chlorophyll-a (Chl-a) in subtropical eastern North/South Pacific (ENP/ESP) upwelling systems. In the ENP, tracers exhibit striated patterns extending up to ~2500 km offshore. Striated signals in SST and SSS are highly correlated with quasi-zonal jets, suggesting that these jets contribute to SST/SSS mesoscale patterns via zonal advection. Striated Chl-a anomalies are collocated with sea surface height (SSH) bands, a possible result of mesoscale eddy trains trapping nutrients and forming striated signals. In the ESP, the signature of striations is only found in SST and coincides with the SSH bands, consistently with quasi-zonal jets located outside major zonal tracer gradients. An interplay between large-scale SST/SSS advection by the quasi-zonal jets, mesoscale SST/SSS advection by the large-scale meridional flow, and eddy advection may explain the persistent ENP hydrographic signature of striations. These results underline the importance of quasi-zonal jets for surface tracer structuring at the mesoscale.

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Similarities and Contrasts in Stationary Striations of Surface Tracers in Pacific Eastern Boundary Upwelling Systems

10.20944/preprints202106.0207.v1 ◽

2021 ◽

Author(s):

Ali Belmadani ◽

Pierre-Amaël Auger ◽

Katherine Gomez ◽

Nikolai Maximenko ◽

Sophie Cravatte

Keyword(s):

Large Scale ◽

Mesoscale Eddy ◽

Meridional Flow ◽

Sea Surface ◽

Chl A ◽

Zonal Jets ◽

Eastern Boundary ◽

Zonal Advection ◽

Highly Correlated ◽

Ocean Properties

Eastern boundary upwelling systems feature strong zonal gradients of physical and biological ocean properties between cool, productive coastal oceans and warm, oligotrophic subtropical gyres. Zonal currents and jets (striations) are therefore likely to contribute to the transport of water properties between coastal and open oceanic regions. Multi-sensor satellite data are used to characterize the signatures of striations in sea surface temperature (SST), salinity (SSS), and chlorophyll-a (Chl-a) in subtropical eastern North/South Pacific (ENP/ESP) upwelling systems. In the ENP, tracers exhibit striated patterns extending up to ~2500 km offshore. Striations in SST and SSS are highly correlated with quasi-zonal jets, suggesting that these jets contribute to SST/SSS mesoscale patterns via zonal advection. Chl-a striations are collocated with sea surface height (SSH) bands, a possible result of mesoscale eddy trains trapping nutrients and forming striated signals. In the ESP, striations are only found in SST and coincide with SSH bands, consistently with quasi-zonal jets located outside major zonal tracer gradients. An interplay between large-scale SST/SSS advection by the quasi-zonal jets, mesoscale SST/SSS advection by the large-scale meridional flow and eddy advection may explain the persistent ENP hydrographic striations. These results underline the importance of quasi-zonal jets for surface tracer structuring at the mesoscale.

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Fish Larvae Response to Biophysical Changes in the Gulf of California, Mexico (Winter-Summer)

Journal of Marine Biology ◽

10.1155/2013/176760 ◽

2013 ◽

Vol 2013 ◽

pp. 1-17 ◽

Cited By ~ 4

Author(s):

Raymundo Avendaño-Ibarra ◽

Enrique Godínez-Domínguez ◽

Gerardo Aceves-Medina ◽

Eduardo González-Rodríguez ◽

Armando Trasviña

Keyword(s):

Environmental Variables ◽

Gulf Of California ◽

Fish Larvae ◽

Mesoscale Eddy ◽

Sea Surface ◽

Mesoscale Structures ◽

Highly Correlated ◽

Biophysical Changes ◽

Mesoscale Processes ◽

Distribution Of Fish

We analyzed the response of fish larvae assemblages to environmental variables and to physical macro- and mesoscale processes in the Gulf of California, during four oceanographic cruises (winter and summer 2005 and 2007). Physical data of the water column obtained through CTD casts, sea surface temperature, and chlorophyllasatellite imagery were used to detect mesoscale structures. Zooplankton samples were collected with standard Bongo net tows. Fish larvae assemblages responded to latitudinal and coastal-ocean gradients, related to inflow of water to the gulf, and to biological production. The 19°C and 21°C isotherms during winter, and 29°C and 31°C during summer, limited the distribution of fish larvae at the macroscale. Between types of eddy, the cyclonic (January) registered high abundance, species richness, and zooplankton volume compared to the other anticyclonic (March) and cyclonic (September). Thermal fronts (Big Islands) of January and July affected the species distribution establishing strong differences between sides. At the mesoscale, eddy and fronts coincided with the isotherms mentioned previously, playing an important role in emphasizing the differences among species assemblages. The multivariate analysis indicated that larvae abundance was highly correlated with temperature and salinity and with chlorophyllaand zooplankton volume during winter and summer, respectively.

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Linking marine fog variability in Atlantic Canada to changes in large-scale atmospheric and marine features

10.5194/egusphere-egu2020-12591 ◽

2020 ◽

Author(s):

Patrick Duplessis ◽

Minghong Zhang ◽

William Perrie ◽

George A Isaac ◽

Rachel Y W Chang

Keyword(s):

Large Scale ◽

Climate Model ◽

Internal Variability ◽

Reanalysis Data ◽

Sea Surface ◽

Atlantic Canada ◽

Climate Projections ◽

The North ◽

Marine Traffic ◽

Highly Correlated

Marine and coastal fog forms mainly from the cooling of warm and moist air advected over a colder sea surface. Atlantic Canada is one of the foggiest regions of the world due to the strong temperature contrast between the two oceanic currents in the vicinity. Recurring periods of low visibility notably disrupt off-shore operations and marine traffic, but also land and air transportation. On longer time-scales, marine fog variability also has a significant impact on the global radiative budget. Clouds, including fog, are the greatest source of uncertainty in the current climate projections because of their complex feedback mechanisms. Meteorological records indicate a significant negative trend in the occurrence of foggy conditions over the past six decades at most airports in Atlantic Canada, with large internal variability, including interannual and interdecadal variations. Using the airport observations, reanalysis data and climate model outputs, we investigated the various variabilities on the trend, at interannual and interdecadal scales, and attempted to address what caused these changes in fog frequency. Our results show that the strength and position of the North Atlantic Subtropical High as well as the sea-surface temperature of the cold and warm waters near Atlantic Canada were highly correlated with fog occurrence. We applied the derived fog indices on climate model outputs and projected the fog trends and variability in the different future climate scenarios. The results from this study will be compared with those obtained from other methods and the implications will be discussed.

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Observed Transport Variability of the Atlantic Subtropical Cells and Their Connection to Tropical Sea Surface Temperature Variability

10.5194/egusphere-egu21-1267 ◽

2021 ◽

Author(s):

Franz Philip Tuchen ◽

Joke F. Lübbecke ◽

Peter Brandt ◽

Yao Fu

Keyword(s):

Surface Temperature ◽

Sea Surface Temperature ◽

Time Scales ◽

Wind Stress ◽

Large Scale ◽

Sea Surface ◽

Ekman Transport ◽

Western Boundary ◽

Eastern Boundary ◽

Stress Changes

The shallow meridional overturning cells of the Atlantic Ocean, the subtropical cells (STCs), consist of poleward Ekman transport at the surface, subduction in the subtropics, equatorward flow at thermocline level and upwelling along the equator and at the eastern boundary. In this study, we provide the first observational estimate of transport variability associated with the horizontal branches of the Atlantic STCs in both hemispheres based on Argo float data and supplemented by reanalysis products.Thermocline layer transport convergence and surface layer transport divergence between 10&#176;N and 10&#176;S are dominated by seasonal variability. Meridional thermocline layer transport anomalies at the western boundary and in the interior basin are anti-correlated and partially compensate each other at all resolved time scales. It is suggested that the seesaw-like relation is forced by the large-scale off-equatorial wind stress changes through low-baroclinic-mode Rossby wave adjustment. We further show that anomalies of the thermocline layer interior transport convergence modulate sea surface temperature (SST) variability in the upwelling regions along the equator and at the eastern boundary at time scales longer than 5 years. Phases of weaker (stronger) interior transport are associated with phases of higher (lower) equatorial SST. At these time scales, STC transport variability is forced by off-equatorial wind stress changes, especially by those in the southern hemisphere. At shorter time scales, equatorial SST anomalies are, instead, mainly forced by local changes of zonal wind stress.

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Interannual Variability of Sea Surface Height over the Black Sea: Relation to Climatic Patterns

Earth Interactions ◽

10.1175/2008ei259.1 ◽

2008 ◽

Vol 12 (10) ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

A. Birol Kara ◽

Charlie N. Barron ◽

Alan J. Wallcraft ◽

Temel Oguz

Keyword(s):

Black Sea ◽

Large Scale ◽

Mesoscale Eddy ◽

Strong Relationship ◽

Sea Surface Height ◽

Sea Surface ◽

Optimal Interpolation ◽

Altimeter Data ◽

The Black Sea ◽

Teleconnection Patterns

Abstract Sea surface height (SSH) variability is presented over the Black Sea during 1993–2005. The 1/4° × 1/4° resolution daily SSH fields are formed using optimal interpolation of available altimeter data. SSH variability reveals distinct maxima in the eastern and western basins, reflecting variations in the corresponding gyres. A joint examination of SSH and sea surface temperature (SST) indicates strong relationship between the two only in winter, with correlations as high as 0.6 or more. This would reflect a steric change in sea surface height due to thermal expansion averaged over a relatively deep winter mixed layer. Newly developed SSH fields also demonstrate a switch to the positive mode of SSH starting from the end of 1996 lasting ≈4 yr. Such a climatic shift is found to be strongly related to large-scale teleconnection patterns. Finally, the daily SSH and SST anomaly fields presented in this paper can supplement various applications in the Black Sea, such as examination of biological production and mesoscale eddy dynamics.

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Global open-ocean biomes: mean and temporal variability

Earth System Science Data ◽

10.5194/essd-6-273-2014 ◽

2014 ◽

Vol 6 (2) ◽

pp. 273-284 ◽

Cited By ~ 52

Author(s):

A. R. Fay ◽

G. A. McKinley

Keyword(s):

Large Scale ◽

Mixed Layer Depth ◽

Open Ocean ◽

Sea Surface ◽

Data Sets ◽

Layer Depth ◽

Future Studies ◽

Chl A ◽

Complex Boundaries ◽

Ice Fraction

Abstract. Large-scale studies of ocean biogeochemistry and carbon cycling have often partitioned the ocean into regions along lines of latitude and longitude despite the fact that spatially more complex boundaries would be closer to the true biogeography of the ocean. Herein, we define 17 open-ocean biomes classified from four observational data sets: sea surface temperature (SST), spring/summer chlorophyll a concentrations (Chl a), ice fraction, and maximum mixed layer depth (maxMLD) on a 1° × 1° grid (available at doi:10.1594/PANGAEA.828650). By considering interannual variability for each input, we create dynamic ocean biome boundaries that shift annually between 1998 and 2010. Additionally we create a core biome map, which includes only the grid cells that do not change biome assignment across the 13 years of the time-varying biomes. These biomes can be used in future studies to distinguish large-scale ocean regions based on biogeochemical function.

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DESIGN AND IMPLEMENTATION OF THE OCEANOGRAPHIC MODELING AND OBSERVATION NETWORK (REMO) FOR PHYSICAL OCEANOGRAPHY STUDIES AND OCEAN FORECASTING

Brazilian Journal of Geophysics ◽

10.22564/rbgf.v31i2.18 ◽

2014 ◽

Vol 31 (2) ◽

Author(s):

Jose Antonio Moreira Lima

Keyword(s):

Atlantic Ocean ◽

Large Scale ◽

North Pacific Ocean ◽

Integrated Approach ◽

Sea Surface ◽

Global Ocean ◽

Height Anomaly ◽

The North ◽

Observation Network ◽

Ocean Forecasting

This paper is concerned with the planning, implementation and some results of the Oceanographic Modeling and Observation Network, named REMO, for Brazilian regional waters. Ocean forecasting has been an important scientific issue over the last decade due to studies related to climate change as well as applications related to short-range oceanic forecasts. The South Atlantic Ocean has a deficit of oceanographic measurements when compared to other ocean basins such as the North Atlantic Ocean and the North Pacific Ocean. It is a challenge to design an ocean forecasting system for a region with poor observational coverage of in-situ data. Fortunately, most ocean forecasting systems heavily rely on the assimilation of surface fields such as sea surface height anomaly (SSHA) or sea surface temperature (SST), acquired by environmental satellites, that can accurately provide information that constrain major surface current systems and their mesoscale activity. An integrated approach is proposed here in which the large scale circulation in the Atlantic Ocean is modeled in a first step, and gradually nested into higher resolution regional models that are able to resolve important processes such as the Brazil Current and associated mesoscale variability, continental shelf waves, local and remote wind forcing, and others. This article presents the overall strategy to develop the models using a network of Brazilian institutions and their related expertise along with international collaboration. This work has some similarity with goals of the international project Global Ocean Data Assimilation Experiment OceanView (GODAE OceanView).

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The Role of Environmental Factors on the Fishery Catch of the Squid Uroteuthis chinensis in the Pearl River Estuary, China

Journal of Marine Science and Engineering ◽

10.3390/jmse9020131 ◽

2021 ◽

Vol 9 (2) ◽

pp. 131

Author(s):

Dongliang Wang ◽

Lijun Yao ◽

Jing Yu ◽

Pimao Chen

Keyword(s):

River Estuary ◽

Pearl River Estuary ◽

Sea Surface ◽

Spatiotemporal Variability ◽

Pearl River ◽

Coastal Current ◽

Catch Per Unit Effort ◽

Chl A ◽

The Pearl River Estuary ◽

The Pearl River

The Pearl River Estuary (PRE) is one of the major fishing grounds for the squid Uroteuthis chinensis. Taking that into consideration, this study analyzes the environmental effects on the spatiotemporal variability of U. chinensis in the PRE, on the basis of the Generalized Additive Model (GAM) and Clustering Fishing Tactics (CFT), using satellite and in situ observations. Results show that 63.1% of the total variation in U. chinensis Catch Per Unit Effort (CPUE) in the PRE could be explained by looking into outside factors. The most important one was the interaction of sea surface temperature (SST) and month, with a contribution of 26.7%, followed by the interaction effect of depth and month, fishermen’s fishing tactics, sea surface salinity (SSS), chlorophyll a concentration (Chl a), and year, with contributions of 12.8%, 8.5%, 7.7%, 4.0%, and 3.1%, respectively. In summary, U. chinensis in the PRE was mainly distributed over areas with an SST of 22–29 °C, SSS of 32.5–34‰, Chl a of 0–0.3 mg × m−3, and water depth of 40–140 m. The distribution of U. chinensis in the PRE was affected by the western Guangdong coastal current, distribution of marine primary productivity, and variation of habitat conditions. Lower stock of U. chinensis in the PRE was connected with La Niña in 2008.

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Satellite-Derived Protein Concentration of Phytoplankton in the Southwestern East/Japan Sea

Journal of Marine Science and Engineering ◽

10.3390/jmse9020189 ◽

2021 ◽

Vol 9 (2) ◽

pp. 189

Author(s):

Hyeonji Bae ◽

Dabin Lee ◽

Jae Joong Kang ◽

Jae Hyung Lee ◽

Naeun Jo ◽

...

Keyword(s):

Protein Concentration ◽

Japan Sea ◽

Biological Properties ◽

Measured Data ◽

Trophic Levels ◽

Coefficient Of Determination ◽

P Value ◽

Chl A ◽

Major Factors

The cellular macromolecular contents and energy value of phytoplankton as primary food source determine the growth of higher trophic levels, affecting the balance and sustainability of oceanic food webs. Especially, proteins are more directly linked with basic functions of phytoplankton biosynthesis and cell division and transferred through the food chains. In recent years, the East/Japan Sea (EJS) has been changed dramatically in environmental conditions, such as physical and chemical characteristics, as well as biological properties. Therefore, developing an algorithm to estimate the protein concentration of phytoplankton and monitor their spatiotemporal variations on a broad scale would be invaluable. To derive the protein concentration of phytoplankton in EJS, the new regional algorithm was developed by using multiple linear regression analyses based on field-measured data which were obtained from 2012 to 2018 in the southwestern EJS. The major factors for the protein concentration were identified as chlorophyll-a (Chl-a) and sea surface nitrate (SSN) in the southwestern EJS. The coefficient of determination (r2) between field-measured and algorithm-derived protein concentrations was 0.55, which is rather low but reliable. The satellite-derived estimation generally follows the 1:1 line with the field-measured data, with Pearson’s correlation coefficient, which was 0.40 (p-value < 0.01, n = 135). No remarkable trend in the long-term annual protein concentration of phytoplankton was found in the study area during our observation period. However, some seasonal difference was observed in winter protein concentration between the 2003–2005 and 2017–2019 periods. The algorithm is developed for the regional East/Japan Sea (EJS) and could contribute to long-term monitoring for climate-associated ecosystem changes. For a better understanding of spatiotemporal variation in the protein concentration of phytoplankton in the EJS, this algorithm should be further improved with continuous field surveys.

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Subseasonal Forecasts of the Northern Queensland Floods of February 2019: Causes and Forecast Evaluation

Atmosphere ◽

10.3390/atmos12060758 ◽

2021 ◽

Vol 12 (6) ◽

pp. 758

Author(s):

Wayne Yuan-Huai Tsai ◽

Mong-Ming Lu ◽

Chung-Hsiung Sui ◽

Yin-Min Cho

Keyword(s):

Large Scale ◽

Deep Convection ◽

Austral Summer ◽

Rainfall Event ◽

Monsoon Depression ◽

Forecast Skill ◽

Sea Surface ◽

Central Pacific ◽

Percentile Rank ◽

Extended Range

During the austral summer 2018/19, devastating floods occurred over northeast Australia that killed approximately 625,000 head of cattle and inundated over 3000 homes in Townsville. In this paper, the disastrous event was identified as a record-breaking subseasonal peak rainfall event (SPRE). The SPRE was mainly induced by an anomalously strong monsoon depression that was modulated by the convective phases of an MJO and an equatorial Rossby (ER) wave. The ER wave originated from an active equatorial deep convection associated with the El Niño warm sea surface temperatures near the dateline over the central Pacific. Based on the S2S Project Database, we analyzed the extended-range forecast skill of the SPRE from two different perspectives, the monsoon depression represented by an 850-hPa wind shear index and the 15-day accumulated precipitation characterized by the percentile rank (PR) and the ratio to the three-month seasonal (DJF) totals. The results of four S2S models of this study suggest that the monsoon depression can maintain the same level of skill as the short-range (3 days) forecast up to 8–10 days. For precipitation parameters, the conclusions are similar to the monsoon depression. For the 2019 northern Queensland SPRE, the model forecast was, in general, worse than the expectation derived from the hindcast analysis. The clear modulation of the ER wave that enhanced the SPRE monsoon depression circulation and precipitation is suspected as the main cause for the lower forecast skill. The analysis procedure proposed in this study can be applied to analyze the SPREs and their associated large-scale drivers in other regions.

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