The Use of Stable Isotope-Based Water Age to Evaluate a Hydrodynamic Model

Mapping Intimacies ◽

10.5194/egusphere-egu2020-6430 ◽

2020 ◽

Author(s):

Edward Gross

Keyword(s):

San Francisco ◽

Hydrodynamic Model ◽

Field Method ◽

Transport Processes ◽

Tracer Transport ◽

Water Age ◽

Transport Time ◽

Good Correspondence ◽

Spatial And Temporal Scales ◽

Fractional Evaporation

Transport time scales are common metrics of the strength of transport processes. Water age is the time elapsed since water from a specific source has entered a study area. An observational method to estimate water age relies on the progressive concentration of the heavier isotopes of hydrogen and oxygen in water that occurs during evaporation. The isotopic composition is used to derive the fraction of water evaporated, and then translated into a transport time scale by applying assumptions of representative water depth and evaporation rate. Water age can also be estimated by a hydrodynamic model using tracer transport equations. Water age calculated by each approach is compared in the Cache Slough Complex, located in the northern San Francisco Estuary, during summer conditions in which this region receives minimal direct freshwater inflow. The model&#8217;s representation of tidal dispersion of Sacramento River water into this backwater region is evaluated. In order to compare directly to isotopic estimates of the fraction of water evaporated (&#8220;fractional evaporation&#8221;) in addition to age, a hydrodynamic model-based property tracking approach analogous to the water age estimation approach is proposed. The age and fractional evaporation model results are analyzed to evaluate assumptions applied in the field-based age estimates. The generally good correspondence between the water age results from both approaches provides confidence in applying the modeling approach to predict age through broader spatial and temporal scales than are practical to assess using the field method, and discrepancies between the two methods suggest aspects of both approaches that may be improved. Model skill in predicting water age is compared to skill in predicting salinity. Compared to water age, salinity observations are shown to be a less useful diagnostic of transport in this low salinity region in which salt inputs are poorly constrained.

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The Use of Stable Isotope-Based Water Age to Evaluate a Hydrodynamic Model

Water ◽

10.3390/w11112207 ◽

2019 ◽

Vol 11 (11) ◽

pp. 2207 ◽

Cited By ~ 5

Author(s):

Gross ◽

Andrews ◽

Bergamaschi ◽

Downing ◽

Holleman ◽

...

Keyword(s):

San Francisco ◽

Hydrodynamic Model ◽

Field Method ◽

Transport Processes ◽

Tracer Transport ◽

Water Age ◽

Transport Time ◽

Good Correspondence ◽

Spatial And Temporal Scales ◽

Fractional Evaporation

Transport time scales are common metrics of the strength of transport processes. Water age is the time elapsed since water from a specific source has entered a study area. An observational method to estimate water age relies on the progressive concentration of the heavier isotopes of hydrogen and oxygen in water that occurs during evaporation. The isotopic composition is used to derive the fraction of water evaporated, and then translated into a transport time scale by applying assumptions of representative water depth and evaporation rate. Water age can also be estimated by a hydrodynamic model using tracer transport equations. Water age calculated by each approach is compared in the Cache Slough Complex, located in the northern San Francisco Estuary, during summer conditions in which this region receives minimal direct freshwater inflow. The model’s representation of tidal dispersion of Sacramento River water into this backwater region is evaluated. In order to compare directly to isotopic estimates of the fraction of water evaporated (“fractional evaporation”) in addition to age, a hydrodynamic model-based property tracking approach analogous to the water age estimation approach is proposed. The age and fractional evaporation model results are analyzed to evaluate assumptions applied in the field-based age estimates. The generally good correspondence between the water age results from both approaches provides confidence in applying the modeling approach to predict age through broader spatial and temporal scales than are practical to assess using the field method, and discrepancies between the two methods suggest aspects of both approaches that may be improved. Model skill in predicting water age is compared to skill in predicting salinity. Compared to water age, salinity observations are shown to be a less useful diagnostic of transport in this low salinity region in which salt inputs are poorly constrained.

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Preliminary map of erosional and depositional provinces and descriptions of sediment-transport processes in the south and central San Francisco Bay region, California

10.3133/mf515 ◽

1973 ◽

Keyword(s):

Sediment Transport ◽

San Francisco ◽

San Francisco Bay ◽

Transport Processes ◽

The South

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Heat, salt and tracer transport in the Plymouth Sound coastal region: a 3-D modelling study

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s002531540300763xh ◽

2003 ◽

Vol 83 (4) ◽

pp. 673-682 ◽

Cited By ~ 19

Author(s):

J.R. Siddorn ◽

J.I. Allen ◽

R.J. Uncles

Keyword(s):

Hydrodynamic Model ◽

Flow Characteristics ◽

Coastal Region ◽

English Channel ◽

Tracer Transport ◽

General Flow ◽

South West ◽

Hydrographic Features ◽

Pollution Events ◽

Modelling Study

A 3-D hydrodynamic model of the circulation, salinity and temperature within the embayment of Plymouth Sound, UK and its surrounding English Channel waters has been implemented. Thorough validation of the model shows that the main hydrographic features of the region, as characterized by these variables, are reproduced. The general flow characteristics, and the resultant distribution of freshwater from the main riverine source (the River Tamar), are described. The potential fate of contaminant releases within Plymouth Sound is investigated. Whitsand Bay, located south-west of Plymouth Sound, is shown to be a likely recipient for a proportion of these contaminants, irrespective of where in the Sound the release occurs, and as such is considered to be vulnerable to pollution events originating there.

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Inferring saline tracer transport characteristics from time-lapse GPR experiments

10.5194/egusphere-egu21-7541 ◽

2021 ◽

Author(s):

Peter-Lasse Giertzuch ◽

Alexis Shakas ◽

Bernard Brixel ◽

Joseph Doetsch ◽

Mohammadreza Jalali ◽

...

Keyword(s):

Electrical Conductivity ◽

Velocity Field ◽

Nuclear Waste ◽

Time Lapse ◽

Transport Processes ◽

Nuclear Waste Repository ◽

Tracer Transport ◽

Tracer Injection ◽

Flow And Transport ◽

Conductivity Sensor

Monitoring and characterization of flow and transport processes in the subsurface has been a key focus of hydrogeological research for several decades. Such processes can be relevant for numerous applications, such as hydrocarbon and geothermal reservoir characterization and monitoring, risk assessment of soil contaminants, or nuclear waste disposal strategies.Monitoring of flow and transport processes in the subsurface is often challenging, as they are usually not directly observable. Here, we present an approach to monitor saline tracer migration through a weakly fractured crystalline rock mass by means of Ground Penetrating Radar (GPR), and we evaluate the data quantitatively in terms of a flow velocity field and localized difference GPR breakthrough curves (DRBTC).Two comparable and repeated tracer injection experiments were performed within saturated rock on the decameter scale. Time-lapse single-hole reflection data were acquired from two different boreholes during these experiments using unshielded and omnidirectional borehole antennas. The individual surveys were analyzed by difference imaging techniques, which allowed ultimately for tracer breakthrough monitoring at different locations in the subsurface. By combining the two complimentary GPR data sets, the 3D tracer velocity field could be reconstructed.Our DRBTCs agree well with measured BTCs of the saline tracer at different electrical conductivity monitoring positions. Additionally, we were able to calculate a DRBTC for a location not previously monitored with borehole sensors. The reconstructed velocity field is in good agreement with previous studies on dye tracer data at the same research locations. Furthermore, we were able to resolve separate flow paths towards different monitoring locations, which could not be inferred from the electrical conductivity sensor data alone. The GPR data thus helped to disentangle the complex flow field through the fractured rock.Out technique can be adapted to other use cases such as 3D monitoring of fluid migration (and thus permeability enhancement) during hydraulic stimulation and tracing fluid contaminants &#8211; e.g. for nuclear waste repository monitoring.

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Simulation of Contaminant Dispersal in an Apartment Building

Volume 2, Parts A and B ◽

10.1115/ht-fed2004-56379 ◽

2004 ◽

Author(s):

Sankalp Soni ◽

Bakhtier Farouk ◽

Charles N. Haas

Keyword(s):

Transport Processes ◽

Apartment Building ◽

Large Eddy Simulation Model ◽

Spatial And Temporal Scales ◽

Eddy Simulation ◽

Large Eddy ◽

Contaminant Dispersal ◽

Detailed Simulation ◽

Time Histories ◽

Ventilation Rates

Bio-terrorism events (like the 2001 anthrax attacks) accentuate the importance of countering these incidents. In order to develop reliable countermeasures for these events, it is essential to understand the associated transport processes. The transport processes involved pose challenges as they occur over wide ranges of spatial and temporal scales. CONTAMW, a multi zone indoor air quality and ventilation analysis program is used to predict the contaminant dispersal in an apartment building. Detailed simulation results and analysis of controlled release of propylene within a generic apartment building is presented. A zonal analysis is carried out for the entire apartment building (using CONTAMW) to obtain time histories of propylene concentration in different zones. The simulations provide the dispersion, transport and contaminant concentration within each zone of the apartment. This study also considers the effect of flow obstructions and ventilation rates on contaminant dispersal. The results are validated with the experimental results reported in Cybyk et al. (1999). We have also simulated propylene transport in the apartment with FDS, a large eddy simulation model.

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Numerical simulation of bedload tracer transport associated with sand bar formation, bank erosion, and channel migration

E3S Web of Conferences ◽

10.1051/e3sconf/20184002013 ◽

2018 ◽

Vol 40 ◽

pp. 02013

Author(s):

Toshiki Iwasaki ◽

Satomi Yamaguchi ◽

Hiroki Yabe

Keyword(s):

Numerical Model ◽

Bank Erosion ◽

Bedload Transport ◽

Transport Processes ◽

Tracer Transport ◽

Channel Migration ◽

River Systems ◽

Sand Bars ◽

Tracer Particles ◽

Bar Formation

An understanding of bedload transport processes is an essential research goal for better prediction of river morphology and morphodynamics as well as the transport and fate of sediment-bound materials in river systems. Passive tracer particles have been used widely to monitor bedload transport processes in rivers by measuring the spatiotemporal distribution of the bedload tracers. Here, we propose a numerical model for reproducing the transport of bedload tracers in river systems, more specifically, the behaviours of bedload tracers under the influence of complex river morphodynamics. A two-dimensional morphodynamic model is combined with a flux-based bedload tracer model with use of the active layer approach. The model is applied to a laboratory experiment that demonstrates the transport processes within the channel of bedload tracers supplied from the floodplain. The numerical model effectively reproduces the main features of the experiment, namely, the bedload tracers supplied from the floodplain due to bank erosion deposit onto sand bars developed within the channel. Because the sand bars cause a very long residence time of the bedload tracers within the bed, the transport speed of the tracers is slowed significantly under the influence of bar formation and channel migration.

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Climatological features of stratospheric streamers in the FUB-CMAM with increased horizontal resolution

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-4-6789-2004 ◽

2004 ◽

Vol 4 (5) ◽

pp. 6789-6822

Author(s):

K. Krüger ◽

U. Langematz ◽

J. L. Grenfell ◽

K. Labitzke

Keyword(s):

East Asia ◽

Total Ozone ◽

Large Scale ◽

Middle Atmosphere ◽

Polar Vortex ◽

Horizontal Resolution ◽

Transport Processes ◽

The Arctic ◽

Future Climate Change ◽

Good Correspondence

Abstract. The purpose of this study is to investigate horizontal transport processes in the winter stratosphere using data with a high spatial and temporal resolution. For this reason the Freie Universität Berlin Climate Middle Atmosphere Model (FUB-CMAM) with its model top at 83 km altitude, increased horizontal resolution T42 and the semi-Lagrangian transport scheme for advecting passive tracers is used. A new result of this paper is the classification of specific transport phenomena within the stratosphere into tropical-subtropical streamer (e.g. Offermann et al., 1999) and polar vortex extrusions hereafter called polar vortex streamers. To investigate the role played by these large-scale structures on the inter-annual and seasonal variability of the observed negative ozone trend in northern mid-latitudes, the global occurrence of such streamers were calculated based on a 10-year model climatology, concentrating on the existence of the Arctic polar vortex. For the identification and counting of streamers, the new method of zonal anomaly was chosen, which in comparison to other methods produced the best result in this study. The analysis of the months October–May yielded a maximum occurrence of tropical-subtropical streamers during Arctic winter and spring in the middle and upper stratosphere. Synoptic maps revealed highest intensities in the subtropics over East Asia with a secondary maximum over the Atlantic in the northern hemisphere. Furthermore, tropical-subtropical streamers exhibited about a four times higher occurrence than polar vortex streamers, indicating that the subtropical barrier is more permeable than the polar vortex barrier (edge) in the model, which is in good correspondence with observations (e.g. Plumb, 2002; Neu et al., 2003). Interesting for the total ozone loss in mid-latitudes is the consideration of the lower stratosphere, where strongest ozone depletion is observed at polar latitudes (WMO, 2003). In this particular region the FUB-CMAM simulated a climatological maximum of 10% occurrence of tropical-subtropical streamers over East-Asia/West Pacific and the Atlantic during early- and mid-winter. The results of this paper demonstrate that the regular occurrence of stratospheric streamers e.g., large-scale mixing processes of tropical-subtropical and polar vortex air masses into mid-latitudes, could play a significant role on the strength and variability of the observed total ozone decrease at mid-latitudes and should not be neglected in future climate change studies.

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Transport Processes in the Gulf of Mexico Along the River-Estuary-Shelf-Ocean Continuum: a Review of Research from the Gulf of Mexico Research Initiative

Estuaries and Coasts ◽

10.1007/s12237-021-01005-1 ◽

2021 ◽

Author(s):

Dubravko Justić ◽

Villy Kourafalou ◽

Giulio Mariotti ◽

Songjie He ◽

Robert Weisberg ◽

...

Keyword(s):

Gulf Of Mexico ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

River Estuary ◽

Deep Ocean ◽

Open Ocean ◽

Transport Processes ◽

Spatial And Temporal Scales ◽

Research Initiative ◽

New Findings

AbstractEstuarine and coastal geomorphology, biogeochemistry, water quality, and coastal food webs in river-dominated shelves of the Gulf of Mexico (GoM) are modulated by transport processes associated with river inputs, winds, waves, tides, and deep-ocean/continental shelf interactions. For instance, transport processes control the fate of river-borne sediments, which in turn affect coastal land loss. Similarly, transport of freshwater, nutrients, and carbon control the dynamics of eutrophication, hypoxia, harmful algal blooms, and coastal acidification. Further, freshwater inflow transports pesticides, herbicides, heavy metals, and oil into receiving estuaries and coastal systems. Lastly, transport processes along the continuum from the rivers and estuaries to coastal and shelf areas and adjacent open ocean (abbreviated herein as “river-estuary-shelf-ocean”) regulate the movements of organisms, including the spatial distributions of individuals and the exchange of genetic information between distinct subpopulations. The Gulf of Mexico Research Initiative (GoMRI) provided unprecedented opportunities to study transport processes along the river-estuary-shelf-ocean continuum in the GoM. The understanding of transport at multiple spatial and temporal scales in this topographically and dynamically complex marginal sea was improved, allowing for more accurate forecasting of the fate of oil and other constituents. For this review, we focus on five specific transport themes: (i) wetland, estuary, and shelf exchanges; (ii) river-estuary coupling; (iii) nearshore and inlet processes; (iv) open ocean transport processes; and (v) river-induced fronts and cross-basin transport. We then discuss the relevancy of GoMRI findings on the transport processes for ecological connectivity and oil transport and fate. We also examine the implications of new findings for informing the response to future oil spills, and the management of coastal resources and ecosystems. Lastly, we summarize the research gaps identified in the many studies and offer recommendations for continuing the momentum of the research provided by the GoMRI effort. A number of uncertainties were identified that occurred in multiple settings. These include the quantification of sediment, carbon, dissolved gasses and nutrient fluxes during storms, consistent specification of the various external forcings used in analyses, methods for smooth integration of multiscale advection mechanisms across different flow regimes, dynamic coupling of the atmosphere with sub-mesoscale and mesoscale phenomena, and methods for simulating finer-scale dynamics over long time periods. Addressing these uncertainties would allow the scientific community to be better prepared to predict the fate of hydrocarbons and their impacts to the coastal ocean, rivers, and marshes in the event of another spill in the GoM.

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Water exchange in a coastal archipelago in the northern Baltic Sea

10.5194/egusphere-egu2020-18546 ◽

2020 ◽

Author(s):

Elina Miettunen ◽

Laura Tuomi ◽

Kai Myrberg

Keyword(s):

Baltic Sea ◽

Hydrodynamic Model ◽

Water Exchange ◽

Particle Model ◽

Water Age ◽

Archipelago Sea ◽

Tracer Particles ◽

Open Sea ◽

Prevailing Wind Direction ◽

Model Setup

The Archipelago Sea, situated in the northern Baltic Sea, consists of over 40 000 small islands and islets. It is a vulnerable area and suffers from continuous nutrient loading from the catchment and also from the background loading from the surrounding open sea areas. We studied water exchange in this complex coastal archipelago by simulating the water age and currents with a 3D hydrodynamic model COHERENS. The Archipelago Sea model setup has a horizontal resolution of c. 460 m and its boundary conditions are from a model setup that covers the whole Baltic Sea with a resolution of 3.7 km. The current fields produced with the hydrodynamic model were used to simulate the transport patterns of passive tracers through the archipelago with a Lagrangian particle model OpenDrift.The mean water age was up to three months in the outer archipelago and up to seven months in the narrowest waterways in the inner archipelago. The effect of rivers on the water age was seen mostly only in the inner archipelago. The transport of passive tracer particles from the open sea areas, across the Archipelago Sea, mostly took place through the outer archipelago. The transport of particles from the outer archipelago towards the inner parts of the archipelago was very sensitive to the geometry and number of islands i.e. density of islands in the area. The prevailing wind direction in the area is from SW, this not being optimal for transport from the outer archipelago to the middle archipelago. For example, with the tracer particles from the southern open sea boundary, most transport to the middle archipelago was seen with SE winds. Transport further to the inner archipelago was limited only to few cases. The results show that the inner archipelago areas are relatively sheltered from transport from the open sea areas and the environmental problems there are in a high extent from local origin.

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