scholarly journals Resilience in Complex Catchment Systems

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 541
Author(s):  
Lindsay Beevers ◽  
Melissa Bedinger ◽  
Kerri McClymont ◽  
Annie Visser-Quinn

In this paper, we explore how we can use catchment resilience as a unifying concept to manage and regulate catchments, using structured reviews to support our perspective. Catchments are complex systems with interrelated natural, social, and technical aspects. The exposure, vulnerability, and resilience of these aspects (separately and in combination) are the latent conditions, which, when triggered by a hydrohazard, result in catchment impacts. In complex catchment systems, resilience is the ability to bounce back, the ability to absorb, and the ability to transform. When all three abilities are accounted for, we are forced to consider the interactions of the catchment system. Six main complexity concepts can be used to frame how we approach evaluating catchment resilience. These concepts are: natural-social-technical aspects, interactions, spatial scales, time scales, multiple forms of evidence, and uncertainty. In analysing these complexity concepts, we have found that there are several gaps in current practice. Requirements for future methodological approaches are suggested. Central to any effective approach is the incorporation of a linking systems or interaction analysis, which draws together the natural-social-technical system in a meaningful way. If our approaches do not begin to acknowledge the interdependencies and interactions, we may miss substantial opportunities to enhance catchment resilience.

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 363
Author(s):  
George Duffy ◽  
Fraser King ◽  
Ralf Bennartz ◽  
Christopher G. Fletcher

CloudSat is often the only measurement of snowfall rate available at high latitudes, making it a valuable tool for understanding snow climatology. The capability of CloudSat to provide information on seasonal and subseasonal time scales, however, has yet to be explored. In this study, we use subsampled reanalysis estimates to predict the uncertainties of CloudSat snow water equivalent (SWE) accumulation measurements at various space and time resolutions. An idealized/simulated subsampling model predicts that CloudSat may provide seasonal SWE estimates with median percent errors below 50% at spatial scales as small as 2° × 2°. By converting these predictions to percent differences, we can evaluate CloudSat snowfall accumulations against a blend of gridded SWE measurements during frozen time periods. Our predictions are in good agreement with results. The 25th, 50th, and 75th percentiles of the percent differences between the two measurements all match predicted values within eight percentage points. We interpret these results to suggest that CloudSat snowfall estimates are in sufficient agreement with other, thoroughly vetted, gridded SWE products. This implies that CloudSat may provide useful estimates of snow accumulation over remote regions within seasonal time scales.


2019 ◽  
Vol 11 (4) ◽  
pp. 1163 ◽  
Author(s):  
Melissa Bedinger ◽  
Lindsay Beevers ◽  
Lila Collet ◽  
Annie Visser

Climate change is a product of the Anthropocene, and the human–nature system in which we live. Effective climate change adaptation requires that we acknowledge this complexity. Theoretical literature on sustainability transitions has highlighted this and called for deeper acknowledgment of systems complexity in our research practices. Are we heeding these calls for ‘systems’ research? We used hydrohazards (floods and droughts) as an example research area to explore this question. We first distilled existing challenges for complex human–nature systems into six central concepts: Uncertainty, multiple spatial scales, multiple time scales, multimethod approaches, human–nature dimensions, and interactions. We then performed a systematic assessment of 737 articles to examine patterns in what methods are used and how these cover the complexity concepts. In general, results showed that many papers do not reference any of the complexity concepts, and no existing approach addresses all six. We used the detailed results to guide advancement from theoretical calls for action to specific next steps. Future research priorities include the development of methods for consideration of multiple hazards; for the study of interactions, particularly in linking the short- to medium-term time scales; to reduce data-intensivity; and to better integrate bottom–up and top–down approaches in a way that connects local context with higher-level decision-making. Overall this paper serves to build a shared conceptualisation of human–nature system complexity, map current practice, and navigate a complexity-smart trajectory for future research.


Author(s):  
Jia-Rong Yeh ◽  
Chung-Kang Peng ◽  
Norden E. Huang

Multi-scale entropy (MSE) was developed as a measure of complexity for complex time series, and it has been applied widely in recent years. The MSE algorithm is based on the assumption that biological systems possess the ability to adapt and function in an ever-changing environment, and these systems need to operate across multiple temporal and spatial scales, such that their complexity is also multi-scale and hierarchical. Here, we present a systematic approach to apply the empirical mode decomposition algorithm, which can detrend time series on various time scales, prior to analysing a signal’s complexity by measuring the irregularity of its dynamics on multiple time scales. Simulated time series of fractal Gaussian noise and human heartbeat time series were used to study the performance of this new approach. We show that our method can successfully quantify the fractal properties of the simulated time series and can accurately distinguish modulations in human heartbeat time series in health and disease.


2004 ◽  
Vol 5 (6) ◽  
pp. 1247-1258 ◽  
Author(s):  
Christopher P. Weaver

Abstract This is Part II of a two-part study of mesoscale land–atmosphere interactions in the summertime U.S. Southern Great Plains. Part I focused on case studies drawn from monthlong (July 1995–97), high-resolution Regional Atmospheric Modeling System (RAMS) simulations carried out to investigate these interactions. These case studies were chosen to highlight key features of the lower-tropospheric mesoscale circulations that frequently arise in this region and season due to mesoscale heterogeneity in the surface fluxes. In this paper, Part II, the RAMS-simulated mesoscale dynamical processes described in the Part I case studies are examined from a domain-averaged perspective to assess their importance in the overall regional hydrometeorology. The spatial statistics of key simulated mesoscale variables—for example, vertical velocity and the vertical flux of water vapor—are quantified here. Composite averages of the mesoscale and large-scale-mean variables over different meteorological or dynamical regimes are also calculated. The main finding is that, during dry periods, or similarly, during periods characterized by large-scale-mean subsidence, the characteristic signature of surface-heterogeneity-forced mesoscale circulations, including enhanced vertical motion variability and enhanced mesoscale fluxes in the lowest few kilometers of the atmosphere, consistently emerges. Furthermore, the impact of these mesoscale circulations is nonnegligible compared to the large-scale dynamics at domain-averaged (200 km × 200 km) spatial scales and weekly to monthly time scales. These findings support the hypothesis that the land– atmosphere interactions associated with mesoscale surface heterogeneity can provide pathways whereby diurnal, mesoscale atmospheric processes can scale up to have more general impacts at larger spatial scales and over longer time scales.


Author(s):  
M. Kiwan ◽  
D.V. Berezkin ◽  
M. Raad ◽  
B. Rasheed

Statement of a problem. One of the main tasks today is to prevent accidents in complex systems, which requires determining their cause. In this regard, several theories and models of the causality of accidents are being developed. Traditional approaches to accident modeling are not sufficient for the analysis of accidents occurring in complex environments such as socio-technical systems, since an accident is not the result of individual component failure or human error. Therefore, we need more systematic methods for the investigation and modeling of accidents. Purpose. Conduct a comparative analysis of accident models in complex systems, identify the strengths and weaknesses of each of these models, and study the feasibility of their use in risk management in socio-technical systems. The paper analyzes the main approaches of accident modeling and their limitations in determining the cause-and-effect relationships and dynamics of modern complex systems. the methodologies to safety and accident models in sociotechnical systems based on systems theory are discussed. The complexity of sociotechnical systems requires new methodologies for modeling the development of emergency management. At the same time, it is necessary to take into account the socio-technical system as a whole and to focus on the simultaneous consideration of the social and technical aspects of the systems. When modeling accidents, it is necessary to take into account the social structures and processes of social interaction, the cultural environment, individual characteristics of a person, such as their abilities and motivation, as well as the engineering design and technical aspects of systems. Practical importance. Based on analyzing various techniques for modeling accidents, as well as studying the examples used in modeling several previous accidents and review the results of this modeling, it is concluded that it is necessary to improve the modeling techniques. The result was the appearance of hybrid models of risk management in socio-technical systems, which we will consider in detail in our next work.


2016 ◽  
Vol 17 (11) ◽  
pp. 2875-2882 ◽  
Author(s):  
Dejene Sahlu ◽  
Efthymios I. Nikolopoulos ◽  
Semu A. Moges ◽  
Emmanouil N. Anagnostou ◽  
Dereje Hailu

Abstract This work presents a first evaluation of the performance of the Integrated Multisatellite Retrievals for GPM (IMERG) precipitation product over the upper Blue Nile basin of Ethiopia. One of the unique features of this study is the availability of hourly rainfall measurements from an experimental rain gauge network in the area. Both the uncalibrated and calibrated versions of IMERG are evaluated, and their performance is contrasted against another high-resolution satellite product, which is the Kalman filter (KF)-based Climate Prediction Center (CPC) morphing technique (CMORPH). The analysis is performed for hourly and daily time scales and at spatial scales that correspond to the nominal resolution of satellite products, which is 0.1° spatial resolution. The period analyzed is focused on a single wet season (May–October 2014). Evaluation is performed using several statistical and categorical error metrics, as well as spatial correlation analysis to assess the ability of satellite products to represent spatial variability of precipitation in the area. Results show that both IMERG products have a better bias ratio and correlation coefficient on both time scales as compared to CMORPH. Comparison statistics show a slight improvement in the skill of detecting rainfall events in IMERG products compared to CMORPH. Results also show a decreasing trend in the detection ability of satellite products for increasing threshold values, highlighting the need to further improve detection during heavy precipitation.


2020 ◽  
pp. 26-34
Author(s):  
Nataliia Smochko

The purpose of this research work is to analyze modern theoretical and methodological approaches to the study of territorial systems of monodevelopment in the theory of social geography. Method. General scientific methods, including analysis, scientific synthesis, analytical method, methods of comparison and generalization were used in the study. Scientific novelty. The article reveals traditional and innovative approaches to identifying and defining the territorial system of mono-development in the geographical space. In substantiating the application of approaches, we used the work of scientists and geographers, who took them into account in the study of complex systems. It has been determined that the leading and traditional approaches in socio-geographical research are historical-geographical (retrospective) and territorial (geospatial), which should be combined with genetic. According to which all geographical phenomena have been considered as processes that have their genesis, dynamics, differences, patterns spatial distribution. To study the processes of system formation, a comprehensive approach is important. It provides a comprehensive analysis of the development of the main factors in the formation of modern socio-economic processes in the regions. The system approach allows to consider functioning and development of the territorial monosystem and its basic types as systems of the territorial organization of a society at various hierarchical levels, to open their integrity and the mechanisms providing effective management of such monodevelopment. At the same time, it has been found that not all the outlined approaches of complex systems can be used to study monosystems in the form in which they were used previously. This is because in the study of systems in retrospect, the application of approaches was focused on the analysis of the structure of the studied objects and the variety of processes that took place between the elements of the studied systems. In the study of monosystems, the researcher should be interested in their development to bifurcation moments and the conditions for further preservation of monosystems. This means that traditional approaches, such as historical-geographical (retrospective) and territorial (geospatial) should be modified to adapt to these tasks. It is important to use innovative approaches: cluster (formation of so-called network structures), behaviorist (explanation of the territorial identity of the monosystem), participatory (strategic planning of the territorial development of the monosystem). Only by combining a variety of approaches will it be possible to obtain a synergistic effect and form a synergistic approach that will provide additional benefits in the study of monosystems and the processes of their functioning. Practical meaning. The results of this study contribute to a deeper socio-geographical understanding of the processes of monodevelopment, their genesis, features of their course and provide an opportunity to model the long-term development of territorial social systems, to achieve expected results due to long-term transformation. They can be used for further study of monosystems of different hierarchical levels, as well as for the development of practical recommendations and programs for the development of individual monoterritories.


Author(s):  
Milan Paluš

Complex systems such as the human brain or the Earth's climate consist of many subsystems interacting in intricate, nonlinear ways. Moreover, variability of such systems extends over broad ranges of spatial and temporal scales and dynamical phenomena on different scales also influence each other. In order to explain how to detect cross-scale causal interactions, we review information-theoretic formulation of the Granger causality in combination with computational statistics (surrogate data method) and demonstrate how this method can be used to infer driver-response relations from amplitudes and phases of coupled nonlinear dynamical systems. Considering complex systems evolving on multiple time scales, the reviewed methodology starts with a wavelet decomposition of a multi-scale signal into quasi-oscillatory modes of a limited bandwidth, described using their instantaneous phases and amplitudes. Then statistical associations, in particular, causality relations between phases or between phases and amplitudes on different time scales are tested using the conditional mutual information. As an application, we present the analysis of cross-scale interactions and information transfer in the dynamics of the El Niño Southern Oscillation. This article is part of the theme issue ‘Coupling functions: dynamical interaction mechanisms in the physical, biological and social sciences’.


Aerospace ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 7
Author(s):  
Solomon O. Obadimu ◽  
Nektarios Karanikas ◽  
Kyriakos I. Kourousis

As part of the airworthiness requirements, an aircraft cannot be dispatched with an inoperative equipment or system unless this is allowed by the Minimum Equipment List (MEL) under any applicable conditions. Commonly, the MEL mirrors the Master MEL (MMEL), which is developed by the manufacturer and approved by the regulator. However, the increasing complexity of aircraft systems and the diversity of operational requirements, environmental conditions, fleet configuration, etc. necessitates a tailored approach to developing the MEL. While it is the responsibility of every aircraft operator to ensure the airworthiness of their aircraft, regulators are also required to publish guidelines to help operators develop their MELs. Currently, there is no approved standard to develop a MEL, and this poses a challenge to both aviation regulators and aircraft operators. This paper reviews current MEL literature, standards and processes as well as MEL related accidents/incidents to offer an overview of the present state of the MEL development and use and reinstate the need for a systematic approach. Furthermore, this paper exposes the paucity of MEL related literature and the ambiguity in MEL regulations. In addition, it was found that inadequate training and guidance on the development and use of MEL as well as lack of prior experience in airworthiness topics can lead to mismanagement and misapplication of the MEL. Considering the challenges outlined above, this study proposes the combination of system engineering and socio-technical system approaches for the development of a MEL.


Author(s):  
Gustaaf C. Cornelis

Abstract This paper describes the activities launched at SCK•CEN, intended to explore ethical and other non-technical aspects when dealing with the time scales considered in the high-level waste disposal program. (1) Especially the issues of retrievability and precaution will be focused on philosophically. Many questions will be raised in order to sensitize all stakeholders for the transdisciplinary character of the transgenerational problem at hand.


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