Assessing the Potential Extent of Damage to Inland Lakes in Eastern Canada due to Acidic Deposition. I. Development and Evaluation of a Simple "Site" Model

1990 ◽  
Vol 47 (1) ◽  
pp. 55-66 ◽  
Author(s):  
David R. Marmorek ◽  
Michael L. Jones ◽  
Charles K. Minns ◽  
Floyd C. Elder

Large scale aquatic effects of acidic deposition have become a prominent environmental issue in North America and Europe. Models are required to assess the potential future impacts of current levels of acidic deposition, and the potential benefits of emission controls. This paper presents a model that uses measurements of current lake chemistry and assumptions about the processes governing acidification, to first estimate original (i.e. preacidification) lake chemistry and then predict the eventual chemistry expected given a specified level of acidic sulphate deposition. The model is deliberately kept simple, so that its input requirements are modest and thus can be met on a regional scale. When applied on a regional scale the model predicts the expected eventual distributions of alkalinity and pH. Application of the model is illustrated for a watershed in north-central Ontario, which includes the area immediately to the south and west of Sudbury. Model-based estimates of current alkalinity are very similar to observed alkalinities. The predicted eventual alkalinity distributions, given current levels of deposition, indicate a trend towards recovery, consistent with other observations in the Sudbury region. A sensitivity analysis of the model indicates that its outputs are highly sensitive to estimates of preacidification lake sulphate levels, and less so to assumptions about the catchment's ability to neutralize incoming acidity. Simple, regional models such as the one presented in this paper should play a more central role than they presently do both in assessment and in the definition of future research and monitoring needs.

1990 ◽  
Vol 47 (4) ◽  
pp. 821-830 ◽  
Author(s):  
C. K. Minns ◽  
J. E. Moore ◽  
D. W. Schindler ◽  
M. L. Jones

Linked regional chemical and biotic models predicted that at least 20% of all lakes in 15 of 38 secondary watersheds in eastern Canada had lost at least 20% of their potential species richness given 1980 acidic sulphate deposition levels; 20% of lakes in 15 watersheds represents circa 55 000 lakes. Fish and molluscs were the most affected of seven aquatic taxonomic groups, and rotifers the least. Mean percent loss of potential richness in all of eastern Canada ranged from 5.0 to 9.5% for the seven groups of biota under 1980 acidic deposition. Sulphur dioxide emission reductions of 42% in Canada and the United States were predicted to reduce the number of affected watersheds to seven, leaving circa 25 000 lakes with 20% or more loss of potential richness. Greater acidic deposition reductions will be needed to minimize the biotic damage affecting large areas of eastern Canada.


1990 ◽  
Vol 47 (1) ◽  
pp. 67-80 ◽  
Author(s):  
Michael L. Jones ◽  
Charles K. Minns ◽  
David R. Marmorek ◽  
Floyd C. Elder

In this, the second of two papers on the development and application of a regional model of surface water acidification, we present the results of initial applications of the model to sensitive regions of eastern Canada. Data used for regional application of the model were obtained from a variety of sources, including acidic sulphate deposition monitoring data and regional lake water chemistry surveys. While these data do not provide a random sample of eastern Canadian lakes, we argue that there are no a priori reasons for expecting highly misleading biases in the data. Results of model applications are presented for observed 1980 sulphate deposition levels and for three alternative emission scenarios. The emission scenarios were simulated using a transfer matrix derived from the AES-LRTAP model. The results suggest that substantial additional damage (declines in surface water alkalinity and pH) is expected in some regions (e.g. northeastern Ontario), even at current deposition levels. The consequences of simple emission reduction strategies differ significantly among regions, suggesting that more complex strategies may be required to produce equitable benefits. To assist interpretation of a complex array of results, we propose an integrated representation of regional impacts that uses quantile-quantile plots of regional distributions of lake chemistry. Finally, we argue that while the results presented are highly uncertain, there are reasons to believe that, if anything, our damage estimates are conservative.


1993 ◽  
Vol 28 (3-5) ◽  
pp. 183-187 ◽  
Author(s):  
D. S. Jeffries ◽  
D. C. L. Lam

The operational definition of the “critical” load for wet SO4 deposition is that which does not increase the regional percent of lakes having pH≤6 for the portion of the population that historically had pH>6. Reviews of the effects of acidic deposition on aquatic biota show that the pH=6 threshold used to determine the critical load is sufficient to protect most organisms. It is inappropriate to specify a single critical load for the whole of eastern Canada due to variability in terrain sensitivity. The Atlantic provinces and easterr Quebec generally have very low critical loads (<8 kg. ha−1.yr−1). The terrain characteristics of this area dictate a critical load very close to background deposition. Lakes in southwestern Quebec and Ontario have critical loads of <8 to >20 kg.ha−1.yr−1 reflecting the wide range in terrain sensitivities that exist in each province.


2008 ◽  
Vol 26 (9) ◽  
pp. 2569-2595 ◽  
Author(s):  
S. Janicot ◽  
C. D. Thorncroft ◽  
A. Ali ◽  
N. Asencio ◽  
G. Berry ◽  
...  

Abstract. The AMMA (African Monsoon Multidisciplinary Analysis) program is dedicated to providing a better understanding of the West African monsoon and its influence on the physical, chemical and biological environment regionally and globally, as well as relating variability of this monsoon system to issues of health, water resources, food security and demography for West African nations. Within this framework, an intensive field campaign took place during the summer of 2006 to better document specific processes and weather systems at various key stages of this monsoon season. This campaign was embedded within a longer observation period that documented the annual cycle of surface and atmospheric conditions between 2005 and 2007. The present paper provides a large and regional scale overview of the 2006 summer monsoon season, that includes consideration of of the convective activity, mean atmospheric circulation and synoptic/intraseasonal weather systems, oceanic and land surface conditions, continental hydrology, dust concentration and ozone distribution. The 2006 African summer monsoon was a near-normal rainy season except for a large-scale rainfall excess north of 15° N. This monsoon season was also characterized by a 10-day delayed onset compared to climatology, with convection becoming developed only after 10 July. This onset delay impacted the continental hydrology, soil moisture and vegetation dynamics as well as dust emission. More details of some less-well-known atmospheric features in the African monsoon at intraseasonal and synoptic scales are provided in order to promote future research in these areas.


2021 ◽  
pp. 1-50
Author(s):  
Benjamin Pohl ◽  
Andrew Lorrey ◽  
Andrew Sturman ◽  
Hervé Quénol ◽  
James Renwick ◽  
...  

AbstractThis paper introduces a set of descriptors applied to weather regimes, that allow for a detailed monitoring of the location and intensity of their atmospheric centers of action (e.g. troughs and ridges) and the gradients between them, when applicable. Descriptors are designed to document the effect of climate variability and change in modulating the character of daily weather regimes, rather than merely their occurrence statistics.As a case study, the methodology is applied to Aotearoa New Zealand (ANZ), using ERA5 ensemble reanalysis data for the period 1979-2019. Here, we analyze teleconnections between the regimes and their descriptors, and large-scale climate variability. Results show a significant modulation of centers of action by the phase of the Southern Annular Mode, with a strong relationship identified with the latitude of atmospheric ridges. Significant associations with El Niño Southern Oscillation are also identified. Modes of large-scale variability have a stronger influence on the regimes’ intrinsic features than their occurrence. This demonstrates the usefulness of such descriptors, which help understand the relationship between mid-latitude transient perturbations and large-scale modes of climate variability.In future research, this methodological framework will be applied to analyze (i) low-frequency changes in weather regimes under climate change, in line with the southward shift of storm tracks, and (ii) regional-scale effects on the climate of ANZ, resulting from interaction with its topography.


1991 ◽  
Vol 48 (4) ◽  
pp. 599-606 ◽  
Author(s):  
Michael L. Jones ◽  
Charles K. Minns ◽  
David R. Marmorek ◽  
Kim J. Heltcher

In this paper, we consider the significance of uncertainty in inputs to the regional surface water acidification model of Marmorek et al. (1990. Can. J. Fish. Aquat. Sci. 47: 55–66). Monte Carlo methods are used to propagate input uncertainty through to measures of uncertainty in the model's overall predictions. We consider four key inputs which represent primary areas of input uncertainty: acidic sulphate deposition (Da), original lake sulphate concentrations ([SO4]0), a watershed neutralization parameter (FW), and an in-lake neutralization parameter (SS). The analysis is repeated for secondary watersheds from north-central Ontario, the Quebec Laurentians, and insular Newfoundland. Uncertainty in Da and [SO4]0 consistently overwhelms the effect of uncertainty in FW and SS on overall model uncertainty. The relative importance of Da decreases as one moves east from the high-deposition regions of central Ontario. We discuss the implications of our results for priority setting for future acidification research and monitoring.


2017 ◽  
Vol 5 (1) ◽  
pp. 70-82
Author(s):  
Soumi Paul ◽  
Paola Peretti ◽  
Saroj Kumar Datta

Building customer relationships and customer equity is the prime concern in today’s business decisions. The emergence of internet, especially social media like Facebook and Twitter, changed traditional marketing thought to a great extent. The importance of customer orientation is reflected in the axiom, “The customer is the king”. A good number of organizations are engaging customers in their new product development activities via social media platforms. Co-creation, a new perspective in which customers are active co-creators of the products they buy and use, is currently challenging the traditional paradigm. The concept of co-creation involving the customer’s knowledge, creativity and judgment to generate value is considered not only an upcoming trend that introduces new products or services but also fitting their need and increasing value for money. Knowledge and innovation are inseparable. Knowledge management competencies and capacities are essential to any organization that aspires to be distinguished and innovative. The present work is an attempt to identify the change in value creation procedure along with one area of business, where co-creation can return significant dividends. It is on extending the brand or brand category through brand extension or line extension. This article, through an in depth literature review analysis, identifies the changes in every perspective of this paradigm shift and it presents a conceptual model of company-customer-brand-based co-creation activity via social media. The main objective is offering an agenda for future research of this emerging trend and ensuring the way to move from theory to practice. The paper acts as a proposal; it allows the organization to go for this change in a large scale and obtain early feedback on the idea presented. 


Author(s):  
Xu Pei-Zhen ◽  
Lu Yong-Geng ◽  
Cao Xi-Min

Background: Over the past few years, the subsynchronous oscillation (SSO) caused by the grid-connected wind farm had a bad influence on the stable operation of the system and has now become a bottleneck factor restricting the efficient utilization of wind power. How to mitigate and suppress the phenomenon of SSO of wind farms has become the focus of power system research. Methods: This paper first analyzes the SSO of different types of wind turbines, including squirrelcage induction generator based wind turbine (SCIG-WT), permanent magnet synchronous generator- based wind turbine (PMSG-WT), and doubly-fed induction generator based wind turbine (DFIG-WT). Then, the mechanisms of different types of SSO are proposed with the aim to better understand SSO in large-scale wind integrated power systems, and the main analytical methods suitable for studying the SSO of wind farms are summarized. Results: On the basis of results, using additional damping control suppression methods to solve SSO caused by the flexible power transmission devices and the wind turbine converter is recommended. Conclusion: The current development direction of the SSO of large-scale wind farm grid-connected systems is summarized and the current challenges and recommendations for future research and development are discussed.


Author(s):  
Matilda A. Haas ◽  
Harriet Teare ◽  
Megan Prictor ◽  
Gabi Ceregra ◽  
Miranda E. Vidgen ◽  
...  

AbstractThe complexities of the informed consent process for participating in research in genomic medicine are well-documented. Inspired by the potential for Dynamic Consent to increase participant choice and autonomy in decision-making, as well as the opportunities for ongoing participant engagement it affords, we wanted to trial Dynamic Consent and to do so developed our own web-based application (web app) called CTRL (control). This paper documents the design and development of CTRL, for use in the Australian Genomics study: a health services research project building evidence to inform the integration of genomic medicine into mainstream healthcare. Australian Genomics brought together a multi-disciplinary team to develop CTRL. The design and development process considered user experience; security and privacy; the application of international standards in data sharing; IT, operational and ethical issues. The CTRL tool is now being offered to participants in the study, who can use CTRL to keep personal and contact details up to date; make consent choices (including indicate preferences for return of results and future research use of biological samples, genomic and health data); follow their progress through the study; complete surveys, contact the researchers and access study news and information. While there are remaining challenges to implementing Dynamic Consent in genomic research, this study demonstrates the feasibility of building such a tool, and its ongoing use will provide evidence about the value of Dynamic Consent in large-scale genomic research programs.


Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1670
Author(s):  
Waheeb Abu-Ulbeh ◽  
Maryam Altalhi ◽  
Laith Abualigah ◽  
Abdulwahab Ali Almazroi ◽  
Putra Sumari ◽  
...  

Cyberstalking is a growing anti-social problem being transformed on a large scale and in various forms. Cyberstalking detection has become increasingly popular in recent years and has technically been investigated by many researchers. However, cyberstalking victimization, an essential part of cyberstalking, has empirically received less attention from the paper community. This paper attempts to address this gap and develop a model to understand and estimate the prevalence of cyberstalking victimization. The model of this paper is produced using routine activities and lifestyle exposure theories and includes eight hypotheses. The data of this paper is collected from the 757 respondents in Jordanian universities. This review paper utilizes a quantitative approach and uses structural equation modeling for data analysis. The results revealed a modest prevalence range is more dependent on the cyberstalking type. The results also indicated that proximity to motivated offenders, suitable targets, and digital guardians significantly influences cyberstalking victimization. The outcome from moderation hypothesis testing demonstrated that age and residence have a significant effect on cyberstalking victimization. The proposed model is an essential element for assessing cyberstalking victimization among societies, which provides a valuable understanding of the prevalence of cyberstalking victimization. This can assist the researchers and practitioners for future research in the context of cyberstalking victimization.


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