scholarly journals Examining the impacts of estimated precipitation isotope (<i>δ</i><sup>18</sup>O) inputs on distributed tracer-aided hydrological modelling

2016 ◽  
Author(s):  
Carly J. Delavau ◽  
Tricia Stadnyk ◽  
Tegan Holmes
Keyword(s):  
Hydrological Modelling ◽  
Data Availability ◽  
Hydrological Models ◽  
Model Simulations ◽  
The Impact ◽  
Drive Model ◽  
Model Structures ◽  
Precipitation Events ◽  
Selection Of ◽  
Modelling Approach

Abstract. Tracer-aided hydrological models are becoming increasingly popular tools as they have documented utility in constraining model parameter space during calibration, reducing model uncertainty, and assisting with selection of appropriate model structures. However, the issue of data availability, particularly input data, proves to be a major challenge associated with this type of application. Tracer-aided hydrological modelling typically requires a time series of isotopes in precipitation (δ18Oppt) to drive model simulations, but unfortunately, throughout much of the world, and particularly in sparsely populated high-latitude regions, these data are not widely available. This study uses the isoWATFLOOD tracer-aided hydrological model to investigate the usefulness of three types of estimated δ18Oppt for model input, and the impact that these data have on model simulations and parameterization in the remote Fort Simpson Basin, NWT, Canada. This study showed that although total simulated streamflow was not significantly impacted by choice of δ18Oppt input, isotopes in streamflow (δ18OSF) simulations and the internal apportionment of water (and therefore, model parameterizations) were impacted, particularly during large precipitation and snowmelt events. This finding highlighted the importance of estimated δ18Oppt to capture both the variability and seasonality in precipitation isotopes as critical for tracer-aided hydrological modelling, especially when precipitation events displayed distinctly different isotopic compositions than that of streamflow. This study achieves an understanding of how isoWATFLOOD can be used in regions with a limited number of δ18Oppt observations, and that the model can be of value in such regions. This study reinforces that a tracer-aided modelling approach assists with resolving hydrograph component contributions, and works towards diagnosing the issue of model equifinality.

Does Wrongdoer Reputation Matter? Impact of Auditor-Wrongdoer Performance and Likeability Reputations on Fellow Auditors' Intention to Take Action and Choice of Reporting Outlet

2011 ◽  
Vol 23 (2) ◽  
pp. 207-234 ◽  
Author(s):  
Jesse C. Robertson ◽  
Chad M. Stefaniak ◽  
Mary B. Curtis
Keyword(s):  
Two Dimensions ◽  
Data Availability ◽  
Good Performer ◽  
Reporting Decisions ◽  
Prior Literature ◽  
Reporting Channel ◽  
Channel Preferences ◽  
Main Effects ◽  
The Impact ◽  
Selection Of

ABSTRACT We investigate the effects of auditor-wrongdoer reputations for performance and likeability on fellow auditors' intentions to take action in response to a questionable audit act. We also use this context to explore auditor selection of reporting outlets, when they do choose to take action. In an experiment with 181 auditors, main effects suggest that likeability reputation is a significant determinant of intention to take action, while performance reputation is marginally significant. As expected, interaction results indicate that auditors have the greatest intention to take action against less likeable, poor performers. Contrary to expectations, intention to take action against a more likeable, good performer is no lower than the mixed conditions. Thus, the influence of the two dimensions of reputation is complex. Additionally, we find auditors are more likely to whistle-blow internally than externally, and through non-anonymous outlets than anonymous outlets. Our contributions include exploring the impact of reputation on the actions of third parties, and advancing prior literature by considering the influence of wrongdoer attributes on reporting decisions and auditors' reporting channel preferences. Data Availability: Data are available from the first author upon request.

scholarly journals Future Flows Hydrology: an ensemble of daily river flow and monthly groundwater levels for use for climate change impact assessment across Great Britain

2012 ◽  
Vol 5 (2) ◽  
pp. 1159-1178 ◽  
Author(s):  
C. Prudhomme ◽  
T. Haxton ◽  
S. Crooks ◽  
C. Jackson ◽  
A. Barkwith ◽  
...  
Keyword(s):  
Climate Change ◽  
Great Britain ◽  
River Flow ◽  
Hydrological Modelling ◽  
Time Slice ◽  
Practical Recommendation ◽  
Hydrological Models ◽  
Groundwater Levels ◽  
Modelling Uncertainty ◽  
The Impact

Abstract. The dataset Future Flows Hydrology was developed as part of the project "Future Flows and Groundwater Levels" to provide a consistent set of transient daily river flow and monthly groundwater levels projections across England, Wales and Scotland to enable the investigation of the role of climate variability on river flow and groundwater levels nationally and how this may change in the future. Future Flows Hydrology is derived from Future Flows Climate, a national ensemble projection derived from the Hadley Centre's ensemble projection HadRM3-PPE 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. Three hydrological models and one groundwater level model were used to derive Future Flows Hydrology, with 30 river sites simulated by two hydrological models to enable assessment of hydrological modelling uncertainty in studying the impact of climate change on the hydrology. Future Flows Hydrology contains an 11-member ensemble of transient projections from January 1951 to December 2098, each associated with a single realisation from a different variant of HadRM3 and a single hydrological model. Daily river flows are provided for 281 river catchments and monthly groundwater levels at 24 boreholes as .csv files containing all 11 ensemble members. When separate simulations are done with two hydrological models, two separate .csv files are provided. Because of potential biases in the climate-hydrology modelling chain, catchment fact sheets are associated with each ensemble. These contain information on the uncertainty associated with the hydrological modelling when driven using observed climate and Future Flows Climate for a period representative of the reference time slice 1961–1990 as described by key hydrological statistics. Graphs of projected changes for selected hydrological indicators are also provided for the 2050s time slice. Limitations associated with the dataset are provided, along with practical recommendation of use. Future Flows Hydrology is freely available for non-commercial use under certain licensing conditions. For each study site, catchment averages of daily precipitation and monthly potential evapotranspiration, used to drive the hydrological models, are made available, so that hydrological modelling uncertainty under climate change conditions can be explored further. doi:10.5285/f3723162-4fed-4d9d-92c6-dd17412fa37b.

scholarly journals Technical note: Hydrology modelling R packages – a unified analysis of models and practicalities from a user perspective

2021 ◽  
Vol 25 (7) ◽  
pp. 3937-3973
Author(s):  
Paul C. Astagneau ◽  
Guillaume Thirel ◽  
Olivier Delaigue ◽  
Joseph H. A. Guillaume ◽  
Juraj Parajka ◽  
...  
Keyword(s):  
Technical Note ◽  
Ease Of Use ◽  
Data Availability ◽  
Hydrological Models ◽  
Rainfall Runoff ◽  
User Perspective ◽  
R Packages ◽  
Spatial Discretisation ◽  
Technical Features ◽  
Selection Of

Abstract. Following the rise of R as a scientific programming language, the increasing requirement for more transferable research and the growth of data availability in hydrology, R packages containing hydrological models are becoming more and more available as an open-source resource to hydrologists. Corresponding to the core of the hydrological studies workflow, their value is increasingly meaningful regarding the reliability of methods and results. Despite package and model distinctiveness, no study has ever provided a comparison of R packages for conceptual rainfall–runoff modelling from a user perspective by contrasting their philosophy, model characteristics and ease of use. We have selected eight packages based on our ability to consistently run their models on simple hydrology modelling examples. We have uniformly analysed the exact structure of seven of the hydrological models integrated into these R packages in terms of conceptual storages and fluxes, spatial discretisation, data requirements and output provided. The analysis showed that very different modelling choices are associated with these packages, which emphasises various hydrological concepts. These specificities are not always sufficiently well explained by the package documentation. Therefore a synthesis of the package functionalities was performed from a user perspective. This synthesis helps to inform the selection of which packages could/should be used depending on the problem at hand. In this regard, the technical features, documentation, R implementations and computational times were investigated. Moreover, by providing a framework for package comparison, this study is a step forward towards supporting more transferable and reusable methods and results for hydrological modelling in R.

scholarly journals The impact of hydrological model structure on the simulation of extreme runoff events

2021 ◽  
Vol 21 (3) ◽  
pp. 961-976
Author(s):  
Gijs van Kempen ◽  
Karin van der Wiel ◽  
Lieke Anna Melsen
Keyword(s):  
Hydrological Model ◽  
Low Flow ◽  
Temperate Climate ◽  
Hydrological Process ◽  
Model Structure ◽  
Hydrological Models ◽  
Climate Zones ◽  
The Impact ◽  
Model Structures ◽  
Runoff Events

Abstract. Hydrological extremes affect societies and ecosystems around the world in many ways, stressing the need to make reliable predictions using hydrological models. However, several different hydrological models can be selected to simulate extreme events. A difference in hydrological model structure results in a spread in the simulation of extreme runoff events. We investigated the impact of different model structures on the magnitude and timing of simulated extreme high- and low-flow events by combining two state-of-the-art approaches: a modular modelling framework (FUSE) and large ensemble meteorological simulations. This combination of methods created the opportunity to isolate the impact of specific hydrological process formulations at long return periods without relying on statistical models. We showed that the impact of hydrological model structure was larger for the simulation of low-flow compared to high-flow events and varied between the four evaluated climate zones. In cold and temperate climate zones, the magnitude and timing of extreme runoff events were significantly affected by different parameter sets and hydrological process formulations, such as evaporation. In the arid and tropical climate zones, the impact of hydrological model structures on extreme runoff events was smaller. This novel combination of approaches provided insights into the importance of specific hydrological process formulations in different climate zones, which can support adequate model selection for the simulation of extreme runoff events.

The Impact on Auditor Judgments of CEO Influence on Audit Committee Independence

2011 ◽  
Vol 30 (4) ◽  
pp. 129-147 ◽  
Author(s):  
Jeffrey R. Cohen ◽  
Lisa Milici Gaynor ◽  
Ganesh Krishnamoorthy ◽  
Arnold M. Wright
Keyword(s):  
Earnings Management ◽  
Financial Reporting ◽  
Audit Committee ◽  
Data Availability ◽  
Audit Committees ◽  
Undue Influence ◽  
Management Incentives ◽  
Auditor Judgments ◽  
The Impact ◽  
Selection Of

SUMMARY Despite the importance of audit committee independence in ensuring the integrity of the financial reporting process, recent research suggests that even when audit committees meet regulatory independence requirements, certain factors, such as undue influence by the CEO over the selection of the audit committee, may diminish the ability of its members to be substantively independent. This study investigates whether auditors consider CEO influence over audit committee independence when making audit judgments where management's incentives to manage earnings differ. In an experiment, we find that audit partners and managers waive a larger amount of a proposed audit adjustment when management's incentives for earnings management are low than when incentives are high. However, when management incentives are high, auditors are less likely to waive as much of an adjustment when the CEO has less influence over the audit committee's independence than when the CEO's influence is greater. In all, the results support our expectations that auditors consider CEO influence on audit committee independence in the resolution of contentious accounting issues. Data Availability: Contact the authors.

scholarly journals The impact of hydrological model structure on the simulation of extreme runoff events

2020 ◽  
Author(s):  
Gijs van Kempen ◽  
Karin van der Wiel ◽  
Lieke Anna Melsen
Keyword(s):  
Hydrological Model ◽  
Low Flow ◽  
Temperate Climate ◽  
Hydrological Process ◽  
Model Structure ◽  
Hydrological Models ◽  
Climate Zones ◽  
The Impact ◽  
Model Structures ◽  
Runoff Events

Abstract. Hydrological extremes affect societies and ecosystems around the world in many ways, stressing the need to make reliable predictions using hydrological models. However, several hydrological models can be selected to simulate extreme events. A difference in hydrological model structure results in a spread in the simulation of extreme runoff events. We investigated the impact of different model structures on the magnitude and timing of simulated extreme high- and low-flow events, by combining two state-of-the-art approaches; a modular modelling framework (FUSE) and large ensemble meteorological simulations. This combination of methods created the opportunity to isolate the impact of specific hydrological process formulations at long return periods without relying on statistical models. We showed that the impact of hydrological model structure was larger for the simulation of low-flow compared to high-flow events and varied between the four evaluated climate zones. In cold and temperate climate zones, the magnitude and timing of extreme runoff events were significantly affected by different parameter sets and hydrological process formulations, such as evaporation. The impact of hydrological model structures on extreme runoff events was smaller in the arid and tropical climate zones. This novel combination of approaches provided insights into the importance of specific hydrological processes formulations in different climate zones, which can support adequate model selection for the simulation of extreme runoff events.

scholarly journals Can assimilation of crowdsourced data in hydrological modelling improve flood prediction?

2017 ◽  
Vol 21 (2) ◽  
pp. 839-861 ◽  
Author(s):  
Maurizio Mazzoleni ◽  
Martin Verlaan ◽  
Leonardo Alfonso ◽  
Martina Monego ◽  
Daniele Norbiato ◽  
...  
Keyword(s):  
Case Studies ◽  
Low Cost ◽  
Hydrological Modelling ◽  
Data Availability ◽  
Hydrological Models ◽  
Flood Prediction ◽  
Technological Advances ◽  
Crowdsourced Data ◽  
Streamflow Data ◽  
Synthetic Time Series

Abstract. Monitoring stations have been used for decades to properly measure hydrological variables and better predict floods. To this end, methods to incorporate these observations into mathematical water models have also been developed. Besides, in recent years, the continued technological advances, in combination with the growing inclusion of citizens in participatory processes related to water resources management, have encouraged the increase of citizen science projects around the globe. In turn, this has stimulated the spread of low-cost sensors to allow citizens to participate in the collection of hydrological data in a more distributed way than the classic static physical sensors do. However, two main disadvantages of such crowdsourced data are the irregular availability and variable accuracy from sensor to sensor, which makes them challenging to use in hydrological modelling. This study aims to demonstrate that streamflow data, derived from crowdsourced water level observations, can improve flood prediction if integrated in hydrological models. Two different hydrological models, applied to four case studies, are considered. Realistic (albeit synthetic) time series are used to represent crowdsourced data in all case studies. In this study, it is found that the data accuracies have much more influence on the model results than the irregular frequencies of data availability at which the streamflow data are assimilated. This study demonstrates that data collected by citizens, characterized by being asynchronous and inaccurate, can still complement traditional networks formed by few accurate, static sensors and improve the accuracy of flood forecasts.

scholarly journals Changing seasonality of moderate and extreme precipitation events in the Alps

2018 ◽  
Vol 18 (7) ◽  
pp. 2047-2056 ◽  
Author(s):  
Stefan Brönnimann ◽  
Jan Rajczak ◽  
Erich M. Fischer ◽  
Christoph C. Raible ◽  
Marco Rohrer ◽  
...  
Keyword(s):  
Extreme Precipitation ◽  
Climate Model ◽  
Global Climate Model ◽  
Model Simulations ◽  
Extreme Precipitation Events ◽  
Rate Of Increase ◽  
Decadal Scale ◽  
The Future ◽  
The Impact ◽  
Precipitation Events

Abstract. The intensity of precipitation events is expected to increase in the future. The rate of increase depends on the strength or rarity of the events; very strong and rare events tend to follow the Clausius–Clapeyron relation, whereas weaker events or precipitation averages increase at a smaller rate than expected from the Clausius–Clapeyron relation. An often overlooked aspect is seasonal occurrence of such events, which might change in the future. To address the impact of seasonality, we use a large ensemble of regional and global climate model simulations, comprising tens of thousands of model years of daily temperature and precipitation for the past, present, and future. In order to make the data comparable, they are quantile mapped to observation-based time series representative of the Aare catchment in Switzerland. Model simulations show no increase in annual maximum 1-day precipitation events (Rx1day) over the last 400 years and an increase of 10 %–20 % until the end of the century for a strong (RCP8.5) forcing scenario. This fits with a Clausius–Clapeyron scaling of temperature at the event day, which increases less than annual mean temperature. An important reason for this is a shift in seasonality. Rx1day events become less frequent in late summer and more frequent in early summer and early autumn, when it is cooler. The seasonality shift is shown to be related to summer drying. Models with decreasing annual mean or summer mean precipitation show this behaviour more strongly. The highest Rx1day per decade, in contrast, shows no change in seasonality in the future. This discrepancy implies that decadal-scale extremes are thermodynamically limited; conditions conducive to strong events still occur during the hottest time of the year on a decadal scale. In contrast, Rx1day events are also limited by other factors. Conducive conditions are not reached every summer in the present, and even less so in the future. Results suggest that changes in the seasonal cycle need to be accounted for when preparing for moderately extreme precipitation events and assessing their socio-economic impacts.

scholarly journals Changing seasonality of moderate and extreme precipitation events in the Alps

2018 ◽  
Author(s):  
Stefan Brönnimann ◽  
Jan Rajczak ◽  
Erich Fischer ◽  
Christoph C. Raible ◽  
Marco Rohrer ◽  
...  
Keyword(s):  
Extreme Precipitation ◽  
Climate Model ◽  
Global Climate Model ◽  
Model Simulations ◽  
Extreme Precipitation Events ◽  
Rate Of Increase ◽  
Decadal Scale ◽  
The Future ◽  
The Impact ◽  
Precipitation Events

Abstract. The intensity of precipitation events is expected to increase in the future. The rate of increase depends on the strength or rarity of the events; very strong and rare events tend to follow the Clausius-Clapeyron relation, whereas weaker events or precipitation averages do not. An often overlooked aspect is seasonal occurrence of such events, which might change in the future. To address the impact of seasonality, we use a large ensemble of regional and global climate model simulations, comprising tens of thousands of model years of daily temperature and precipitation for the past, present and future. In order to make the data comparable, they are quantile-mapped to observation-based time series representative of the Aare catchment in Switzerland. Model simulations show no increase in annual maximum 1-day precipitation events (Rx1day) over the last 400 yrs and an increase of 10–20 % until the end of the century for a strong (RCP8.5) forcing scenario. This fits with a Clausius-Clapeyron scaling of temperature at the event day, which increases less than annual mean temperature. An important reason for this is a shift in seasonality. Rx1day events become less frequent in late summer and more frequent in early summer and early fall, when it is cooler. The seasonality shift is shown to be related to summer drying. Models with decreasing annual mean or summer mean precipitation show this behavior more strongly. The highest Rx1day per decade, in contrast, shows no change in seasonality in the future. This discrepancy implies that decadal-scale extremes are thermodynamically limited; conditions conducive to strong events still occur during hottest time of the year on a decadal scale. In contrast, Rx1day events are also limited by other factors. Conducive conditions are not reached every summer in the present, and even less so in the future. Results suggest that changes in the seasonal cycle need to be accounted for when preparing for moderately extreme precipitation events and assessing their socio-economic impacts.

scholarly journals Insights from a new methodology to optimize rain gauge weighting for rainfall-runoff models

2019 ◽  
Author(s):  
Ashley J. Wright ◽  
David E. Robertson ◽  
Jeffrey P. Walker ◽  
Valentijn R. N. Pauwels
Keyword(s):  
Conceptual Understanding ◽  
Flood Forecasting ◽  
Rain Gauge ◽  
Hydrological Models ◽  
Rainfall Runoff ◽  
Model Dynamics ◽  
Areal Rainfall ◽  
The Impact ◽  
Streamflow Simulation ◽  
Selection Of

Abstract. Floods continue to devastate societies and their economies. Resilient societies commonly incorporate flood forecasting into their strategy to mitigate the impact of floods. Hydrological models which simulate the rainfall-runoff process are at the core of flood forecasts. To date operational flood forecasting models use areal rainfall estimates that are based on geographical features. This paper introduces a new methodology to optimally blend the weighting of gauges for the purpose of obtaining superior flood forecasts. For a selection of 7 Australian catchments this methodology was able to yield improvements of 15.3 % and 7.1 % in optimization and evaluation periods respectively. Catchments with a low gauge density, or an overwhelming majority of gauges with a low proportion of observations available, are not well suited to this new methodology. Models which close the water balance and demonstrate internal model dynamics that are consistent with a conceptual understanding of the rainfall-runoff process yielded consistent improvement in streamflow simulation skill.

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