Improving Flood Forecasting Using Conditional Bias Aware Assimilation Of Streamflow Observations And Dynamic Assessment Of Flow Dependent Information Content
Download Improving Flood Forecasting Using Conditional Bias Aware Assimilation Of Streamflow Observations And Dynamic Assessment Of Flow Dependent Information Content PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Improving Flood Forecasting Using Conditional Bias Aware Assimilation Of Streamflow Observations And Dynamic Assessment Of Flow Dependent Information Content book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages.
Improving Flood Forecasting Using Conditional Bias-aware Assimilation of Streamflow Observations and Dynamic Assessment of Flow-dependent Information Content
Accurate forecasting of floods is a long-standing challenge in hydrology and water management. Data assimilation (DA) is a popular technique used to improve forecast accuracy by updating the model states in real time using the uncertainty-quantified actual and model-simulated observations. A particular challenge in DA concerns the ability to improve the prediction of hydrologic extremes, such as floods, which have particularly large impacts on society. Almost all DA methods used today are based on least squares minimization. As such, they are subject to conditional bias (CB) in the presence of observational uncertainties which often leads to under- and over-prediction of the predict and over the upper and lower tails, respectively. To address the adverse impact of CB in DA, conditional bias penalized Kalman filter (CBPKF) and conditional bias penalized ensemble Kalman filter (CBEnKF) have recently been proposed which minimize a weighted sum of the error variance and expectation of the CB squared. Whereas CBPKF and CBEnKF significantly improve the accuracy of the estimates over the tails, they deteriorate performance near the median due to the added penalty. To address the above, this work introduces CB-aware DA, which adaptively weights the CB penalty term in real time, and assesses the flow-dependent information content in observation and model prediction using the degrees of freedom for signal (DFS), which serves as a skill score for information fusion. CB-aware DA is then comparatively evaluated with ensemble Kalman filter in which the marginal information content of observations and its flow dependence are assessed given the hydrologic model used. The findings indicate that CB-aware DA with information content analysis offers an objective framework for improving DA performance for prediction of extremes and dynamically balancing the predictive skill of hydrologic models, quality and frequency of hydrologic observations, and scheduling of DA cycles for improving operational flood forecasting cost-effectively.
Improving Flood Prediction Assimilating Uncertain Crowdsourced Data into Hydrologic and Hydraulic Models
In recent years, the continued technological advances have led to the spread of low-cost sensors and devices supporting crowdsourcing as a way to obtain observations of hydrological variables in a more distributed way than the classic static physical sensors. The main advantage of using these type of sensors is that they can be used not only by technicians but also by regular citizens. However, due to their relatively low reliability and varying accuracy in time and space, crowdsourced observations have not been widely integrated in hydrological and/or hydraulic models for flood forecasting applications. Instead, they have generally been used to validate model results against observations, in post-event analyses. This research aims to investigate the benefits of assimilating the crowdsourced observations, coming from a distributed network of heterogeneous physical and social (static and dynamic) sensors, within hydrological and hydraulic models, in order to improve flood forecasting. The results of this study demonstrate that crowdsourced observations can significantly improve flood prediction if properly integrated in hydrological and hydraulic models. This study provides technological support to citizen observatories of water, in which citizens not only can play an active role in information capturing, evaluation and communication, leading to improved model forecasts and better flood management.
Flood Forecasting Using Machine Learning Methods
Nowadays, the degree and scale of flood hazards has been massively increasing as a result of the changing climate, and large-scale floods jeopardize lives and properties, causing great economic losses, in the inundation-prone areas of the world. Early flood warning systems are promising countermeasures against flood hazards and losses. A collaborative assessment according to multiple disciplines, comprising hydrology, remote sensing, and meteorology, of the magnitude and impacts of flood hazards on inundation areas significantly contributes to model the integrity and precision of flood forecasting. Methodologically oriented countermeasures against flood hazards may involve the forecasting of reservoir inflows, river flows, tropical cyclone tracks, and flooding at different lead times and/or scales. Analyses of impacts, risks, uncertainty, resilience, and scenarios coupled with policy-oriented suggestions will give information for flood hazard mitigation. Emerging advances in computing technologies coupled with big-data mining have boosted data-driven applications, among which Machine Learning technology, with its flexibility and scalability in pattern extraction, has modernized not only scientific thinking but also predictive applications. This book explores recent Machine Learning advances on flood forecast and management in a timely manner and presents interdisciplinary approaches to modelling the complexity of flood hazards-related issues, with contributions to integrative solutions from a local, regional or global perspective.