A fully coupled spatially distributed hydrologic-hydrodynamic model for the Barotse Floodplain, Upper Zambezi

2021 ◽  
Author(s):  
Innocent C. Chomba ◽  
Kawawa Banda ◽  
Hessel Winsemius ◽  
Eunice Makungu ◽  
Dennis Hughes ◽  
...  
Keyword(s):  
Large Scale ◽  
River Flow ◽  
Coupled Model ◽  
Feedback Mechanism ◽  
Wet Season ◽  
Time Step ◽  
Groundwater Levels ◽  
Inundation Modelling ◽  
Inundation Extent ◽  
Fully Coupled

<p>Floodplains play important roles in global hydrological and biogeochemical cycles, and many socioeconomic activities also depend on water resources in floodplains. Although considered as critical for the formation and preservation of floodplains, hydrology in floodplains has been hard to characterise. In recent years the demand for an understanding of the hydrological and hydrodynamic processes for the Barotse floodplains is ever increasing especially with the advent of climate change/variability, and expected upstream developments. Yet, the multi-way interactions between river flows, wetland inundation, and groundwater are complex, and poorly understood, compromising studying these changes. Most hydrological and hydrodynamic models applied for large-scale hydrological and inundation modelling lack an advanced floodplain-groundwater feedback mechanism, and thus may over predict or under predict inundation extent, depth, and downstream river flow. This is because groundwater re-infiltration and evaporation from the floodplains over a longer time scale than the flood process are not accounted for.  Hence, the main objective of this current study is to show the very first attempt to a fully coupled model for the Barotse floodplain. The hypothesis is that a fully coupled model will result in larger groundwater dynamics, a slower rise of inundation, and possibly a longer recession tail. To test this hypothesis, we setup two experiments; (i) in the first experiment, WFLOW runs and feeds upstream flows into LISFLOOD. This is sort of the classic approach, and similar to earlier studies, and also does not necessarily require a time-step based coupling; (ii) in the second experiment, WFLOW runs and feeds into Lisflood_FP, and Lisflood_FP then returns water into the WFLOW model. This an experiment where we re-infiltrate water into wflow and by doing so, let groundwater levels adapt so that additional reinfiltrated water, decrease the amount of flood water, increase groundwater levels more during the wet season, and provide a higher recession tail downstream. Our model environment and experiments are available through https://github.com/Innochomba/barotse.</p>

scholarly journals Explicit silicate cycling in the Kiel Marine Biogeochemistry Model, version 3 (KMBM3) embedded in the UVic ESCM version 2.9

2020 ◽  
Author(s):  
Karin Kvale ◽  
David P. Keller ◽  
Wolfgang Koeve ◽  
Katrin J. Meissner ◽  
Chris Somes ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Primary Production ◽  
Large Scale ◽  
Climate Model ◽  
Net Primary Production ◽  
Coupled Model ◽  
Co2 Concentration ◽  
Ecosystem Model ◽  
New Model ◽  
Fully Coupled

Abstract. We describe and test a new model of biological marine silicate cycling, implemented in the University of Victoria Earth System Climate Model (UVic ESCM) version 2.9. This new model adds diatoms, which are a key aspect of the biological carbon pump, to an existing ecosystem model. The new model performs well against important ocean biogeochemical indicators and captures the large-scale features of the marine silica cycle. Furthermore it is computationally efficient, allowing both fully-coupled, long-timescale transient simulations, as well as "offline" transport matrix spinups. We assess the fully-coupled model against modern ocean observations, the historical record since 1960, and a business-as-usual atmospheric CO2 forcing to the year 2300. The model simulates a global decline in net primary production (NPP) of 1.3 % having occurred since the 1960s, with the strongest declines in the tropics, northern mid-latitudes, and Southern Ocean. The simulated global decline in NPP reverses after the year 2100 (forced by the extended RCP CO2 concentration scenario), and NPP returns to pre-industrial rates by 2300. This recovery is dominated by increasing primary production in the Southern Ocean, mostly by calcifying phytoplankton. Large increases in calcifying phytoplankton in the Southern Ocean offset a decline in the low latitudes, producing a global net calcite export in 2300 that varies only slightly from pre-industrial rates. Diatoms migrate southward in our simulations, following the receding Antarctic ice front, but are out-competed by calcifiers across most of their pre-industrial Southern Ocean habitat. Global opal export production thus drops to 50 % of its pre-industrial value by 2300. Model nutrients phosphate, silicate, and nitrate build up along the Southern Ocean particle export pathway, but dissolved iron (for which ocean sources are held constant) increases in the upper ocean. This different behaviour of iron is attributed to a reduction of low-latitude NPP (and consequently, a reduction in both uptake and export and particle, including calcite, scavenging), an increase in seawater temperatures (raising the solubility of particle forms), and stratification that "traps" the iron near the surface. These results are meant to serve as a baseline for sensitivity assessments to be undertaken with this model in the future.

Prediction capabilities of GeoFlood for the delineation of flood-prone areas: the Tiber River case study

2021 ◽  
Author(s):  
Claudia D'Angelo ◽  
Paola Passalacqua ◽  
Aldo Fiori ◽  
Elena Volpi
Keyword(s):  
Large Scale ◽  
River Flow ◽  
Computational Cost ◽  
Roughness Coefficient ◽  
Mapping Procedure ◽  
Hand Model ◽  
Inundation Mapping ◽  
Flood Inundation Mapping ◽  
Inundation Extent ◽  
Flood Prone Areas

<p>Land use and delineation of flood-prone areas require valuable and effective tools, such as flood mapping. Local authorities, in order to prevent and mitigate the effects of flood events, need simplified methodologies for the definition of preliminary flooded areas at a large scale. In this work, we focus on the workflow GeoFlood, which can rapidly convert real-time and forecasted river flow conditions into flooding maps. It is built upon two methodologies, GeoNet and the HAND model, making use only of high-resolution DTMs to define the geomorphological and hydraulic information necessary for flood inundation mapping, thus allowing for large-scale simulations at a reasonable economical and computational cost. GeoFlood potential is tested over the mid-lower portion of the river Tiber (Italy), investigating the conditions under which it is able to reproduce successful inundation extent, considering a 200-year return period scenario. Results are compared to authority maps obtained through standard detailed hydrodynamic approaches. In order to analyze the influence of the main parameters involved, such as DTM resolution, channel segmentation length, and roughness coefficient, a sensitivity analysis is performed. GeoFlood proved to produce efficient and robust results, obtaining a slight over-estimation comparable to that provided by standard costly methods. It is a valid and relatively inexpensive framework for inundation mapping over large scales, considering all the uncertainties involved in any mapping procedure. Also, it can be useful for a preliminary delineation of regions where the investigation based on detailed hydrodynamic models is required.</p>

scholarly journals Temporal variability of the selected flood parameters in the Biebrza River valley

2011 ◽  
Vol 43 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Stefan Ignar ◽  
Anna Maksymiuk-Dziuban ◽  
Dorota Mirosław-Świątek ◽  
Jarosław Chormański ◽  
Tomasz Okruszko ◽  
...  
Keyword(s):  
Linear Regression ◽  
Hydrodynamic Model ◽  
Temporal Variability ◽  
River Flow ◽  
Regression Method ◽  
River Valley ◽  
Linear Regression Method ◽  
Time Step ◽  
Average Technique ◽  
Inundation Extent

Temporal variability of the selected flood parameters in the Biebrza River valley The paper presents the application of the hydrodynamic one-dimensional model of river flow based on St Venant equations for calculation of annual floods characteristics in the Lower Biebrza River Basin situated in the Northeast of Poland. This model was combined with the Digital Elevation Model (DEM) for determining of area of flooding, its mean depth and flood volume. The model was calibrated using measurements of flood extent and verified comparing calculated flood extent to satellite images. The water level values calculated with the numerical model of flood-flow for cross-sections were next used to determine the digital model of the floodwater table in the valley. Then, inundation extent maps and water depth maps were calculated for whole area of the valley by overlaying the DEM and water table layers. This procedure, flood simulations with the hydrodynamic model and GIS analysis for determinations of inundation extent, was repeated for each day of the analyzed period of 1966-2000. A set of each year maximum calculated areas of flooding with related mean water depths and flood volumes was created and it was submitted to the trend analysis in order to determine possible change tendencies. Statistical analysis of three above described time series of annual flood characteristics was conducted with the use of moving average technique and linear regression method. Moving averages were calculate in two variants: with time step of 5 years and of 10 years. Next, linear trends were calculated by linear regression method. The results indicate that the developed hydrodynamic model of river flow combined with the DEM was useful for the calculation of annual maximum floods in the Lower Biebrza Valley and their parameters. Analysis of calculated flood parameters variability within the analyzed time period of 1961-2000 show decreasing trends for investigated area. This means that results of climate changes are perceptible in investigated area and they form serious danger to riparian wetlands.

scholarly journals Future Flows Climate: an ensemble of 1-km climate change projections for hydrological application in Great Britain

2012 ◽  
Vol 4 (1) ◽  
pp. 143-148 ◽  
Author(s):  
C. Prudhomme ◽  
S. Dadson ◽  
D. Morris ◽  
J. Williamson ◽  
G. Goodsell ◽  
...  
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Great Britain ◽  
River Flow ◽  
Potential Evapotranspiration ◽  
Time Step ◽  
Climate Change Projections ◽  
Groundwater Levels ◽  
Temperature And Precipitation ◽  
Climate Change Uncertainty

Abstract. The dataset Future Flows Climate was developed as part of the project ''Future Flows and Groundwater Levels'' to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications, and to enable climate change uncertainty and climate variability to be accounted for in the assessment of their possible impacts on the environment. Future Flows Climate is derived from the Hadley Centre's ensemble projection HadRM3-PPE that is part of the basis of UKCP09 and includes projections in available precipitation (water available to hydrological processes after snow and ice storages have been accounted for) and potential evapotranspiration. It corresponds to an 11-member ensemble of transient projections from January 1950 to December 2098, each a single realisation from a different variant of HadRM3. Data are provided on a 1-km grid over the HadRM3 land areas at a daily (available precipitation) and monthly (PE) time step as netCDF files. Because systematic biases in temperature and precipitation were found between HadRM3-PPE and gridded temperature and precipitation observations for the 1962–1991 period, a monthly bias correction procedure was undertaken, based on a linear correction for temperature and a quantile-mapping correction (using the gamma distribution) for precipitation followed by a spatial downscaling. Available precipitation was derived from the bias-corrected precipitation and temperature time series using a simple elevation-dependant snow-melt model. Potential evapotranspiration time series were calculated for each month using the FAO-56 Penman-Monteith equations and bias-corrected temperature, cloud cover, relative humidity and wind speed from HadRM3-PPE along with latitude of the grid and the day of the year. Future Flows Climate is freely available for non-commercial use under certain licensing conditions. It is the dataset used to generate Future Flows Hydrology, an ensemble of transient projections of daily river flow and monthly groundwater time series for representative river basins and boreholes in Great Britain. doi:10.5285/bad1514f-119e-44a4-8e1e-442735bb9797.

scholarly journals Future Flows Climate: an ensemble of 1-km climate change projections for hydrological application in Great Britain

2012 ◽  
Vol 5 (1) ◽  
pp. 475-490 ◽  
Author(s):  
C. Prudhomme ◽  
S. Dadson ◽  
D. Morris ◽  
J. Williamson ◽  
G. Goodsell ◽  
...  
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Great Britain ◽  
River Flow ◽  
Potential Evapotranspiration ◽  
Time Step ◽  
Climate Change Projections ◽  
Groundwater Levels ◽  
Temperature And Precipitation ◽  
Climate Change Uncertainty

Abstract. 1. The dataset Future Flows Climate was developed as part of the project "Future Flows and Groundwater Levels" to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications, and to enable for climate change uncertainty and climate variability to be accounted for in the assessment of their possible impacts on the environment. 2. Future Flows Climate is derived from the Hadley Centre's ensemble Projection HadRM3-PPE that is part of the basis of UKCP09 and includes projections in available precipitation (water available to hydrological processes after snow and ice storages have been accounted for) and potential evapotranspiration. It corresponds to an 11-member ensemble of transient projections from January 1950 to December 2098, each a single realisation from a different variant of HadRM3. Data are provided on a 1-km grid over the HadRM3 land areas at a daily (available precipitation) and monthly (PE) time step as NetCDF files. 3. Because systematic biases in temperature and precipitation were found between HadRM3-PPE and gridded temperature and precipitation observations for the 1962–1991 period, a monthly bias correction procedure was undertaken, based on a linear correction for temperature and a quantile-mapping correction (using the gamma distribution) for precipitation followed by a spatial downscaling. Available precipitation was derived from the bias-corrected precipitation and temperature time series using a simple elevation-dependant snow-melt model. Potential evapotranspiration time series were calculated for each month using the FAO-56 Penman Montieth equations and bias-corrected temperature, cloud cover, relative humidity and wind speed from HadRM3-PPE along with latitude of the grid and the day of the year. 4. Future Flows Climate is freely available for non commercial use under certain licensing conditions. It is the dataset used to generate Future Flows Hydrology, an ensemble of transient projections of daily river flow and monthly groundwater time series for representative river basins and boreholes in Great Britain. 5. doi:10.5285/bad1514f-119e-44a4-8e1e-442735bb9797

The ponds of Hattuša – early groundwater management in the Hittite kingdom

2013 ◽  
Vol 13 (3) ◽  
pp. 692-698
Author(s):  
Hartmut Wittenberg ◽  
Andreas Schachner
Keyword(s):  
Groundwater Management ◽  
Urban Area ◽  
Groundwater Monitoring ◽  
Large Scale ◽  
Asia Minor ◽  
Wet Season ◽  
Long Distance ◽  
Groundwater Levels ◽  
Steep Terrain ◽  
The City

From about 1650 until 1200 BC Hattuša (pronounced Hattusha) was the capital of the Hittite Empire in central Asia Minor. On the steep terrain of today's ruined city lived and worked thousands of people whose homes, cattle, tools and places of worship had to be supplied with water. The question arose regarding how water was conveyed into the large-scale ponds in the urban area. The silted East Ponds (36,000 m3) and South Ponds (20,000 m3) have been excavated since the 1980s. A supply of the large volumes of water by a long pipeline from outside the city was repeatedly discussed. Due to the topographic, hydraulic and geo-hydrological conditions however, a long distance supply would have been uneconomic and also unnecessary. Still today, many willow fountains in the region are fed by artesian groundwater. It was therefore assumed that the ponds were cut into the slope aquifers and filled during the wet season. To verify this hypothesis, groundwater monitoring stations were installed in the autumn of 2009 directly uphill of the pond banks. Observed groundwater levels 2009–2011 are low in summer but rise above the former pond surfaces during winter. The Hittites used exfiltrating groundwater also in other reservoirs avoiding hefty and strongly varying surface inflows.

scholarly journals Dynamical implications of prescribing part of a coupled system: Results from a low-order model

1998 ◽  
Vol 5 (3) ◽  
pp. 167-179 ◽  
Author(s):  
A. T. Wittenberg ◽  
J. L. Anderson
Keyword(s):  
Statistical Tests ◽  
Coupled Model ◽  
Coupled System ◽  
Climate Modelling ◽  
Initial State ◽  
Time Step ◽  
Common Procedure ◽  
True Solution ◽  
System A ◽  
Fully Coupled

Abstract. It is a common procedure in climate modelling to specify dynamical system components from an external source; a prominent example is the forcing of an atmospheric model with observed sea surface temperatures. In this paper, we examine the dynamics of such forced models using a simple prototype climate system. A particular fully coupled run of the model is designated the "true" solution, and an ensemble of perturbed initial states is generated by adding small errors to the "true" initial state. The perturbed ensemble is then integrated for the same period as the true solution, using both the fully-coupled model and a model in which the ocean is prescribed exactly from the true solution at every time step. Although the prescribed forcing is error-free, the forced-atmosphere ensemble is shown to converge to spurious solutions. Statistical tests show that neither the time-mean state nor the variability of the forced ensemble is consistent with the fully-coupled system. A stability analysis reveals the source of the inconsistency, and suggests that such behaviour may be a more general feature of models with prescribed subsystems. Possible implications for model validation and predictability are discussed.

Stress self-sensing in Amplified Piezoelectric Actuators through a fully-coupled model of hysteresis

2020 ◽  
Vol 579 ◽  
pp. 411894
Author(s):  
Valerio Apicella ◽  
Carmine Stefano Clemente ◽  
Daniele Davino ◽  
Damiano Leone ◽  
Ciro Visone
Keyword(s):  
Coupled Model ◽  
Piezoelectric Actuators ◽  
Fully Coupled

scholarly journals Impact of air–sea coupling on the climate change signal over the Iberian Peninsula

2021 ◽  
Author(s):  
Alba de la Vara ◽  
William Cabos ◽  
Dmitry V. Sein ◽  
Claas Teichmann ◽  
Daniela Jacob
Keyword(s):  
Climate Change ◽  
Iberian Peninsula ◽  
Mediterranean Sea ◽  
Large Scale ◽  
Regional Distribution ◽  
Coupled Model ◽  
Climate Change Signal ◽  
The North ◽  
The Mediterranean ◽  
The Impact

AbstractIn this work we use a regional atmosphere–ocean coupled model (RAOCM) and its stand-alone atmospheric component to gain insight into the impact of atmosphere–ocean coupling on the climate change signal over the Iberian Peninsula (IP). The IP climate is influenced by both the Atlantic Ocean and the Mediterranean sea. Complex interactions with the orography take place there and high-resolution models are required to realistically reproduce its current and future climate. We find that under the RCP8.5 scenario, the generalized 2-m air temperature (T2M) increase by the end of the twenty-first century (2070–2099) in the atmospheric-only simulation is tempered by the coupling. The impact of coupling is specially seen in summer, when the warming is stronger. Precipitation shows regionally-dependent changes in winter, whilst a drier climate is found in summer. The coupling generally reduces the magnitude of the changes. Differences in T2M and precipitation between the coupled and uncoupled simulations are caused by changes in the Atlantic large-scale circulation and in the Mediterranean Sea. Additionally, the differences in projected changes of T2M and precipitation with the RAOCM under the RCP8.5 and RCP4.5 scenarios are tackled. Results show that in winter and summer T2M increases less and precipitation changes are of a smaller magnitude with the RCP4.5. Whilst in summer changes present a similar regional distribution in both runs, in winter there are some differences in the NW of the IP due to differences in the North Atlantic circulation. The differences in the climate change signal from the RAOCM and the driving Global Coupled Model show that regionalization has an effect in terms of higher resolution over the land and ocean.

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