scholarly journals Lagrangian simulation and tracking of the mesoscale eddies contaminated by Fukushima-derived radionuclides

Ocean Science ◽  
2017 ◽  
Vol 13 (3) ◽  
pp. 453-463 ◽  
Author(s):  
Sergey V. Prants ◽  
Maxim V. Budyansky ◽  
Michael Y. Uleysky
Keyword(s):  
Velocity Field ◽  
Mesoscale Eddies ◽  
In Situ Measurements ◽  
Water Masses ◽  
Fukushima Accident ◽  
Lagrangian Particles ◽  
Lagrangian Simulation ◽  
History Of ◽  
The Kuroshio

Abstract. A Lagrangian methodology is developed to simulate, track, document and analyze the origin and history of water masses in ocean mesoscale features. It aims to distinguish whether water masses inside the mesoscale eddies originated from the main currents in the Kuroshio–Oyashio confluence zone. By computing trajectories for a large number of synthetic Lagrangian particles advected by the AVISO velocity field after the Fukushima accident, we identify and track the mesoscale eddies which were sampled in the cruises in 2011 and 2012 and estimate their risk of being contaminated by Fukushima-derived radionuclides. The simulated results are compared with in situ measurements, showing a good qualitative correspondence.

scholarly journals Lagrangian simulation and tracking of the mesoscale eddies contaminated by Fukushima-derived radionuclides

2017 ◽  
Author(s):  
Sergey V. Prants ◽  
Maxim V. Budyansky ◽  
Michael Yu. Uleysky
Keyword(s):  
Velocity Field ◽  
Mesoscale Eddies ◽  
In Situ Measurements ◽  
Water Masses ◽  
Fukushima Accident ◽  
Lagrangian Simulation ◽  
Confluence Zone ◽  
History Of ◽  
The Kuroshio

Abstract. A Lagrangian methodology is elaborated to simulate, track, document and analyze origin and history of water masses in ocean mesoscale features. It is aimed to distinguish water masses inside the mesoscale eddies originated from the main currents in the Kuroshio–Oyashio confluence zone. Computing trajectories for a large number of synthetic tracers advected by the AVISO velocity field after the Fukushima accident, we identify and track the mesoscale eddies which have been sampled in the cruises in 2011 and 2012 and estimate their risk to be contaminated by Fukushima-derived radionuclides. The simulated results are compared with in situ measurements to be in a good qualitative correspondence.

scholarly journals Long distance particle transport to the central Ionian Sea

2021 ◽  
Author(s):  
Léo Berline ◽  
Andrea Michelangelo Doglioli ◽  
Anne Petrenko ◽  
Stéphanie Barrillon ◽  
Boris Espinasse ◽  
...  
Keyword(s):  
High Resolution ◽  
In Situ Measurements ◽  
Water Masses ◽  
Ionian Sea ◽  
Long Distance ◽  
The West ◽  
The North ◽  
Lagrangian Modeling ◽  
Sicily Channel

Abstract. In the upper layers of the Ionian Sea, young Mediterranean Atlantic Waters (MAW) flowing eastward from the Sicily channel meet old MAW. In May 2017, during the PEACETIME cruise, fluorescence and particle content sampled at high resolution revealed unexpected heterogeneity in the central Ionian. Surface salinity measurements, together with altimetry-derived and hull-mounted ADCP currents, describe a zonal pathway of AW entering the Ionian Sea, consistent with the so-called cyclonic mode in the North Ionian Gyre. The ION-Tr transect, located ~19–20° E–~36° N turned out to be at the crossroad of three water masses, mostly coming from the west, north and from an isolated anticyclonic eddy northeast of ION-Tr. Using Lagrangian numerical simulations, we suggest that the contrast in particle loads along ION-Tr originates from particles transported from these three different water masses. Waters from the west, identified as young AW carried by a strong southwestward jet, were intermediate in particle load, probably originating from the Sicily channel. Water mass originating from the north was carrying abundant particles, probably originating from northern Ionian, or further from the south Adriatic. Waters from the eddy, depleted in particles and Chl-a may originate from south of Peloponnese, where the Pelops eddy forms. The central Ionian Sea hence appears as a mosaic area, where waters of contrasted biological history meet. This contrast is particularly clear in spring, when blooming and non-blooming areas co-occur. Particle abundance in situ measurements are useful to discriminate water masses and derive circulation, together with T-S properties. Interpreting the complex dynamics of physical-biogeochemical coupling from discrete measurements made at isolated stations at sea is a big challenge. The combination of multi-parametric in situ measurements at high resolution with remote sensing and Lagrangian modeling appears as one proper way to address this challenge.

scholarly journals Long-distance particle transport to the central Ionian Sea

2021 ◽  
Vol 18 (24) ◽  
pp. 6377-6392
Author(s):  
Léo Berline ◽  
Andrea Michelangelo Doglioli ◽  
Anne Petrenko ◽  
Stéphanie Barrillon ◽  
Boris Espinasse ◽  
...  
Keyword(s):  
High Resolution ◽  
In Situ Measurements ◽  
Water Masses ◽  
Ionian Sea ◽  
Long Distance ◽  
The West ◽  
The North ◽  
Lagrangian Modeling ◽  
Sicily Channel

Abstract. Together with T–S properties, particle abundance in situ measurements are useful to discriminate water masses and derive circulation patterns. In the upper layers of the Ionian Sea, the fresher Atlantic Waters (AW) recently crossing the Sicily Channel meet the resident and saltier AW, which circulated cyclonically in the eastern basin and modified after evaporation and eventually cooling. In May 2017, during the PEACETIME cruise, fluorescence and particle abundance sampled at high resolution revealed unexpected heterogeneity in the central Ionian Sea. Surface salinity measurements, together with altimetry-derived and hull-mounted acoustic Doppler current profiler (ADCP) currents, describe a zonal pathway of AW entering the Ionian Sea, consistent with the so-called cyclonic mode in the North Ionian Gyre. The ION-Tr transect, located between 19–20∘ E at approximately 36∘ N, turned out to be at the crossroads of three water masses, mostly coming from the west, north and an isolated anticyclonic eddy northeast of ION-Tr. Using Lagrangian numerical simulations, we suggest that the contrast in particle loads along ION-Tr originates from particles transported from these three different water masses. Waters from the west, identified as AW carried by a strong southwestward jet, were moderate in particle load, probably originating from the Sicily Channel. The water mass from the north, carrying abundant particles, probably originated in the northern Ionian Sea, or further away from the south Adriatic Sea. Waters from the eddy, depleted in particles and chl a, may originate from south of the Peloponnese, where the Pelops eddy forms. The central Ionian Sea hence appears as a mosaic area, where waters of contrasted biological history meet. This contrast is particularly clear in spring, when blooming and non-blooming areas co-occur. Interpreting the complex dynamics of physical–biogeochemical coupling from discrete measurements made at isolated stations at sea is a challenge. The combination of multiparametric in situ measurements at high resolution with remote sensing and Lagrangian modeling appears as one adequate way to address this challenge.

scholarly journals Monitoring presence and streaming patterns of Icelandic volcanic ash during its arrival to Slovenia

2011 ◽  
Vol 8 (8) ◽  
pp. 2351-2363 ◽  
Author(s):  
F. Gao ◽  
S. Stanič ◽  
K. Bergant ◽  
T. Bolte ◽  
F. Coren ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Atmospheric Aerosol ◽  
Volcanic Ash ◽  
Satellite Images ◽  
In Situ Measurements ◽  
Volcanic Origin ◽  
Air Masses ◽  
X Ray ◽  
History Of

Abstract. The eruption of the Eyjafjallajökull volcano starting on 14 April 2010 resulted in the spreading of volcanic ash over most parts of Europe. In Slovenia, the presence of volcanic ash was monitored using ground-based in-situ measurements, lidar-based remote sensing and airborne in-situ measurements. Volcanic origin of the detected aerosols was confirmed by subsequent spectral and chemical analysis of the collected samples. The initial arrival of volcanic ash to Slovenia was first detected through the analysis of precipitation, which occurred on 17 April 2010 at 01:00 UTC and confirmed by satellite-based remote sensing. At this time, the presence of low clouds and occasional precipitation prevented ash monitoring using lidar-based remote sensing. The second arrival of volcanic ash on 20 April 2010 was detected by both lidar-based remote sensing and airborne in-situ measurements, revealing two or more elevated atmospheric aerosol layers. The ash was not seen in satellite images due to lower concentrations. The identification of aerosol samples from ground-based and airborne in-situ measurements based on energy-dispersive X-ray spectroscopy confirmed that a fraction of particles were volcanic ash from the Eyjafjallajökull eruption. To explain the history of the air masses bringing volcanic ash to Slovenia, we analyzed airflow trajectories using ECMWF and HYSPLIT models.

Study of the Kuroshio/Ryukyu Current system based on satellite-altimeter and in situ measurements

2008 ◽  
Vol 64 (6) ◽  
pp. 937-950 ◽  
Author(s):  
Magdalena Andres ◽  
Jae-Hun Park ◽  
Mark Wimbush ◽  
Xiao-Hua Zhu ◽  
Kyung-Il Chang ◽  
...  
Keyword(s):  
Current System ◽  
In Situ Measurements ◽  
Satellite Altimeter ◽  
Ryukyu Current ◽  
The Kuroshio

The Carbon:²³⁴Thorium ratios of sinking particles in the California Current Ecosystem 2: Examination of a thorium sorption, desorption, and particle transport model

2019 ◽  
Author(s):  
Michael Stukel ◽  
Thomas Kelly
Keyword(s):  
Organic Carbon ◽  
Water Column ◽  
Particulate Organic Carbon ◽  
Transport Model ◽  
California Current ◽  
In Situ Measurements ◽  
Power Law Distribution ◽  
Sinking Particles ◽  
Organic Carbon Concentration

Thorium-234 (234Th) is a powerful tracer of particle dynamics and the biological pump in the surface ocean; however, variability in carbon:thorium ratios of sinking particles adds substantial uncertainty to estimates of organic carbon export. We coupled a mechanistic thorium sorption and desorption model to a one-dimensional particle sinking model that uses realistic particle settling velocity spectra. The model generates estimates of 238U-234Th disequilibrium, particulate organic carbon concentration, and the C:234Th ratio of sinking particles, which are then compared to in situ measurements from quasi-Lagrangian studies conducted on six cruises in the California Current Ecosystem. Broad patterns observed in in situ measurements, including decreasing C:234Th ratios with depth and a strong correlation between sinking C:234Th and the ratio of vertically-integrated particulate organic carbon (POC) to vertically-integrated total water column 234Th, were accurately recovered by models assuming either a power law distribution of sinking speeds or a double log normal distribution of sinking speeds. Simulations suggested that the observed decrease in C:234Th with depth may be driven by preferential remineralization of carbon by particle-attached microbes. However, an alternate model structure featuring complete consumption and/or disaggregation of particles by mesozooplankton (e.g. no preferential remineralization of carbon) was also able to simulate decreasing C:234Th with depth (although the decrease was weaker), driven by 234Th adsorption onto slowly sinking particles. Model results also suggest that during bloom decays C:234Th ratios of sinking particles should be higher than expected (based on contemporaneous water column POC), because high settling velocities minimize carbon remineralization during sinking.

Evaluation of reanalysis and satellite-based sea surface winds using in situ measurements from Chinese Antarctic Expeditions

2013 ◽  
Vol 24 (3) ◽  
pp. 147
Author(s):  
Ming LI ◽  
Qinghua YANG ◽  
Jiechen ZHAO ◽  
Lin ZHANG ◽  
Chunhua LI ◽  
...  
Keyword(s):  
In Situ Measurements ◽  
Sea Surface ◽  
Surface Winds ◽  
Sea Surface Winds
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