A study of effectiveness of the ensemble long-term forecasts of spring floods issued with physically based models of the river runoff formation

Currently, long-term estimates can be obtained either under the assumption of statistical stationarity of hydrometeorological processes using actual series of observations for the previous decades, i.e., in fact, by extrapolating “frozen” current probabilistic estimates to the future, or by modeling (calculation) based on equilibrium climatic scenarios under the assumption of statistical sustainability of runoff series, according to which parameterization of forecast models of runoff formation is conducted. The article considers the methodology of partially infinite hydrology, which includes sustainable forecasting of runoff and diagnostics of bifurcations of its formation, allows solving fundamentally new hydrological problems (including problems of engineering hydrology) related to the possibility of obtaining longterm estimates of probabilistic characteristics of long-term river runoff under the conditions of evolutionary changes in the runoff formation factors (climate and anthropogenic activity in catchment areas). Using the methods and patterns of partially infinite hydrology and relying only on the available hydrometeorological information (obtained at the state network of standard observations), known climatic scenarios and plans for the socio-economic development of the territory, the following main results have been obtained: 1) river basins have been diagnosed (as well as time intervals in the future), the ones in which (and when) it is possible to change the additive mechanism of the smooth evolution of the flow formation process to a bifurcation mechanism (the appearance of bifurcation foci) being identified, i.e. engineering hydrology documents can be questioned; 2) a methodology has been developed for sustainable forecasting of the probabilistic characteristics of long-term river runoff using various options for its formation models (unimodal, polymodal, one-dimensional, multidimensional, etc.).

Download Full-text

Zonal aspects of the influence of forest cover change on runoff in northern river basins of Central Siberia

Forest Ecosystems ◽

10.1186/s40663-021-00316-w ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

A. Onuchin ◽

Т. Burenina ◽

А. Shvidenko ◽

D. Prysov ◽

A. Musokhranova

Keyword(s):

River Runoff ◽

Catchment Area ◽

Forest Cover ◽

River Basins ◽

Forest Vegetation ◽

Middle Taiga ◽

Northern Eurasia ◽

Runoff Formation ◽

Forest Tundra

Abstract Background Assessment of the reasons for the ambiguous influence of forests on the structure of the water balance is the subject of heated debate among forest hydrologists. Influencing the components of total evaporation, forest vegetation makes a significant contribution to the process of runoff formation, but this process has specific features in different geographical zones. The issues of the influence of forest vegetation on river runoff in the zonal aspect have not been sufficiently studied. Results Based on the analysis of the dependence of river runoff on forest cover, using the example of nine catchments located in the forest-tundra, northern and middle taiga of Northern Eurasia, it is shown that the share of forest cover in the total catchment area (percentage of forest cover, FCP) has different effects on runoff formation. Numerical experiments with the developed empirical models have shown that an increase in forest cover in the catchment area in northern latitudes contributes to an increase in runoff, while in the southern direction (in the middle taiga) extensive woody cover of catchments “works” to reduce runoff. The effectiveness of geographical zonality in regards to the influence of forests on runoff is more pronounced in the forest-tundra zone than in the zones of northern and middle taiga. Conclusion The study of this problem allowed us to analyze various aspects of the hydrological role of forests, and to show that forest ecosystems, depending on environmental conditions and the spatial distribution of forest cover, can transform water regimes in different ways. Despite the fact that the process of river runoff formation is controlled by many factors, such as temperature conditions, precipitation regime, geomorphology and the presence of permafrost, the models obtained allow us to reveal general trends in the dependence of the annual river runoff on the percentage of forest cover, at the level of catchments. The results obtained are consistent with the concept of geographic determinism, which explains the contradictions that exist in assessing the hydrological role of forests in various geographical and climatic conditions. The results of the study may serve as the basis for regulation of the forest cover of northern Eurasian river basins in order to obtain the desired hydrological effect depending on environmental and economic conditions.

Download Full-text

On the residual strength of aging cast iron trunk mains: Physically-based models for asset failure

Materials Science and Engineering A ◽

10.1016/j.msea.2016.03.029 ◽

2016 ◽

Vol 663 ◽

pp. 204-212 ◽

Cited By ~ 8

Author(s):

Azadeh Fahimi ◽

Timothy S. Evans ◽

Jeff Farrow ◽

David A. Jesson ◽

Mike J. Mulheron ◽

...

Keyword(s):

Cast Iron ◽

Residual Strength ◽

Physically Based ◽

Physically Based Models

Download Full-text

A Comparative Study of Data and Physically Based Gas Turbine Modeling for Long-Term Monitoring Scenarios: Part II — Emission Prediction Utilizing Different Levels of Design Information

Volume 6: Ceramics; Controls, Diagnostics, and Instrumentation; Education; Manufacturing Materials and Metallurgy ◽

10.1115/gt2018-76650 ◽

2018 ◽

Author(s):

Moritz Lipperheide ◽

Thomas Bexten ◽

Manfred Wirsum ◽

Martin Gassner ◽

Stefano Bernero

Keyword(s):

Gas Turbine ◽

A Priori ◽

Model Development ◽

Fine Tuning ◽

Plant Operator ◽

Engine Model ◽

Physically Based ◽

Design Type ◽

The Impact

Reliable engine and emission models allow for an online monitoring of commercial gas turbine operation and help the plant operator and the original equipment manufacturer (OEM) to ensure emission compliance of the aging engine. However, model development and validation require fine-tuning on the particular engines, which may differ in a fleet of a single design type by production, assembly and aging status. For this purpose, Artificial Neural Networks (ANN) offer a good and fast alternative to traditional physically-based engine modeling, because the model creation and adaption is merely an automatized process in commercially available software environments. However, ANN performance depends strongly on the availability of suitable data and a-priori data processing. The present work investigates the impact of specific engine information from the OEM’s design tools on ANN performance. As an alternative to a strictly data-based benchmark approach, engine characteristics were incorporated into ANNs by a pre-processing of the raw measurements with a simplified engine model. The resulting ‘virtual’ measurements, i.e. hot gas temperatures, then served as inputs to ANN training and application during long-term gas turbine operation. When processed input parameters were used for ANNs, overall long-term NOx prediction improved by 55%, and CO prediction by 16% in terms of RMSE, yielding comparable overall RMSE values to the physically-based model.

Download Full-text

Performance of the dynamically dimensioned search algorithm: influence of parameter initialization strategy when calibrating a physically based hydrological model

Hydrology Research ◽

10.2166/nh.2017.139 ◽

2017 ◽

Vol 49 (4) ◽

pp. 971-988 ◽

Cited By ~ 5

Author(s):

Franck Lespinas ◽

Ashu Dastoor ◽

Vincent Fortin

Keyword(s):

Search Algorithm ◽

Low Cost ◽

Initial Parameter ◽

Cost Strategy ◽

Physically Based ◽

Physically Based Models ◽

Calibration Solution ◽

Low Cost Strategy ◽

Parameter Values ◽

Initialization Strategy

Abstract This study presents an evaluation of the performance of the dynamically dimensioned search (DDS) algorithm when calibrating the hydrological component of the Visualizing Ecosystems for Land Management Assessments (VELMA) ecohydrological model. Two calibration strategies were tested for the initial parameter values: (1) a ‘high-cost strategy’, where 100 sets of initial parameter values were randomly chosen within the overall parameter space, and (2) a ‘low-cost strategy’, where a unique set of initial parameter values was derived from the available field data. Both strategies were tested for six different values of the maximum number of model evaluations ranging between 100 and 10,000. Results revealed that DDS is able to converge rapidly to a good parameter calibration solution of the VELMA hydrological component regardless of the parameter initialization strategy used. The accuracy and convergence efficiency of the DDS algorithm were, however, slightly better for the low-cost strategy. This study suggests that initializing the parameter values of complex physically based models using information on the watershed characteristics can increase the efficiency of the automatic calibration procedures.

Download Full-text

Evaluating performances of simplified physically based models for landslide susceptibility

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-12-13217-2015 ◽

2015 ◽

Vol 12 (12) ◽

pp. 13217-13256 ◽

Cited By ~ 5

Author(s):

G. Formetta ◽

G. Capparelli ◽

P. Versace

Keyword(s):

Landslide Susceptibility ◽

Goodness Of Fit ◽

Shallow Landslides ◽

Model Parameters ◽

Test Case ◽

Susceptibility Analysis ◽

Physically Based ◽

Private And Public ◽

Physically Based Models

Abstract. Rainfall induced shallow landslides cause loss of life and significant damages involving private and public properties, transportation system, etc. Prediction of shallow landslides susceptible locations is a complex task that involves many disciplines: hydrology, geotechnical science, geomorphology, and statistics. Usually to accomplish this task two main approaches are used: statistical or physically based model. Reliable models' applications involve: automatic parameters calibration, objective quantification of the quality of susceptibility maps, model sensitivity analysis. This paper presents a methodology to systemically and objectively calibrate, verify and compare different models and different models performances indicators in order to individuate and eventually select the models whose behaviors are more reliable for a certain case study. The procedure was implemented in package of models for landslide susceptibility analysis and integrated in the NewAge-JGrass hydrological model. The package includes three simplified physically based models for landslides susceptibility analysis (M1, M2, and M3) and a component for models verifications. It computes eight goodness of fit indices by comparing pixel-by-pixel model results and measurements data. Moreover, the package integration in NewAge-JGrass allows the use of other components such as geographic information system tools to manage inputs-output processes, and automatic calibration algorithms to estimate model parameters. The system was applied for a case study in Calabria (Italy) along the Salerno-Reggio Calabria highway, between Cosenza and Altilia municipality. The analysis provided that among all the optimized indices and all the three models, the optimization of the index distance to perfect classification in the receiver operating characteristic plane (D2PC) coupled with model M3 is the best modeling solution for our test case.

Download Full-text

A New Approach to Mapping Landslide hazards: a probabilistic integration of empirical and physically based models in the North Cascades of Washington, USA - Research Data

HydroShare Resources ◽

10.4211/hs.6d8c3c46f4c8422796f28584eb9bdfaa ◽

2019 ◽

Cited By ~ 1

Keyword(s):

Research Data ◽

North Cascades ◽

New Approach ◽

The North ◽

Landslide Hazards ◽

Physically Based ◽

Physically Based Models

Download Full-text

ESTIMATION OF LONG-TERM CHANGES IN QUALITATIVE CHARACTERISTICS OF THE OKA RIVER RUNOFF

Prirodoobustrojstvo ◽

10.26897/1997-6011-2021-5-98-104 ◽

2021 ◽

pp. 98-104

Author(s):

G. KH. ISMAIYLOV ◽

◽

N. V. MURASCHENKOVA ◽

I. G. ISMAIYLOVA

Keyword(s):

River Runoff ◽

Maximum Concentration ◽

Temporal Dynamics ◽

Ammonium Nitrogen ◽

Oil Products ◽

Copper Compounds ◽

Long Term Changes ◽

The City ◽

Qualitative Characteristics

The results of the analysis and assessment of long-term changes in the qualitative characteristics of the Oka River runoff are presented. To analyze the temporal dynamics of the variability of the average annual and maximum concentrations of pollutants in the runoff of the Oka River, we used long-term observational data on typical pollutants for the period 1984-2019. The assessment of the state of the quality of surface waters of the Oka River was carried out according to the values of the concentrations of pollutants in the upper, middle and lower reaches of the river. The dynamics of the main pollutants of the following indicators is considered: ammonium nitrogen, oil products, copper and zinc compounds and easily oxidized organic substances. It was found that in the upper reaches of the river (according to observations of the Oka – Orel city) the main pollutants are ammonium nitrogen and copper compounds, the average annual concentrations of which respectively increased to 9 values. A similar situation was observed downstream of the river (the Oka River – Kaluga city). As a result of the analysis, it was revealed that more noticeable changes in the concentration of pollutants are observed in the section of the river from the city of Murom to the city of Dzerzhinsk. Near the city of Murom, the content of oil products in the water sharply increases. From the beginning of the study period (1984) and until 1995, the average annual concentration varied from 5 to 30 values, and the maximum concentration in the year in creased to 87 values. After 2000, the content of oil products in water dropped sharply and the average annual value did not exceed 3 values, and the maximum concentration was 4-6 values. The paper analyzes the frequency of cases of exceeding the maximum permissible concentrations of pollutants in the Oka River in the mouth of the river. There was a high repeatability of the content of copper compounds in water, which varied from 70 to 88%. The frequency of cases of excess of easily oxidized organic matter in the mouth of the Oka River varied from 64 to 74%. Relatively low, although stable, the repeatability of the content of oil products in water remained, which ranged from 23 to 42%.

Download Full-text