scholarly journals Modeling impacts of highly regulated inflow on thermal regime and water age in a shallow reservoir

2013 ◽  
Vol 15 (4) ◽  
pp. 1312-1325 ◽  
Author(s):  
Binbin Wu ◽  
Guoqiang Wang ◽  
Changming Liu ◽  
Zongxue Xu
Keyword(s):  
Water Temperature ◽  
Thermal Regime ◽  
Northern China ◽  
Transport Processes ◽  
Water Age ◽  
Shallow Reservoir ◽  
Thermal Effluent ◽  
Negative Effect ◽  
The Impact ◽  
Shallow Reservoirs

Thermal regime and transport of dissolved pollutants, strongly related to water quality and algae bloom in reservoirs, may be quantized by indicators of water temperature and water age, respectively, and these indicators are more spatially and temporally variant in shallow reservoirs. Here, a two-dimensional model was used for studying characteristics of the indicators in Douhe Reservoir, based on data of the year 2008. Douhe Reservoir is a typical shallow reservoir in Northern China, characterized by highly regulated inflow and thermal effluent. The impacts of the regulated inflow on reservoir thermal regime and water age were then analyzed through numerical experiments. The results show that the effects of inflow are associated with the flow circulations induced by inflow, thermal effluent, and wind. The most efficient inflows for alleviating thermal pollution and improving water exchange are 32.5 and 19.5 m3/s, respectively. A positive logarithmic correlation is found between water temperature and water age under the impact of inflow, while thermal effluent and wind have a slightly negative effect on the correlation. These findings provide useful information for better understanding the complex hydrodynamic and mass transport processes in a shallow reservoir.

A regional analysis of the impact of dams on water temperature in medium-size rivers in eastern Canada

2016 ◽  
Vol 73 (12) ◽  
pp. 1885-1897 ◽  
Author(s):  
Audrey Maheu ◽  
André St-Hilaire ◽  
Daniel Caissie ◽  
Nassir El-Jabi ◽  
Guillaume Bourque ◽  
...  
Keyword(s):  
Water Temperature ◽  
Thermal Regime ◽  
Regional Scale ◽  
Regional Analysis ◽  
Annual Runoff ◽  
Rate Of Change ◽  
Medium Size ◽  
Regulated Rivers ◽  
Eastern Canada ◽  
The Impact

Various studies have helped gain a better understanding of the thermal impacts of dams on a site-specific basis, but very few studies have compared the thermal impacts of varying types of dams within the same region. In this study, we conducted a regional-scale assessment of the impacts of dams on the thermal regime of 13 medium-size rivers in eastern Canada. The objectives of this study were to identify features of the thermal regime of rivers that are predominantly impacted by dams and to compare the impacts associated with different types of regulation (run-of-river, storage, peaking). The thermal regime of regulated and unregulated rivers was characterized using 15 metrics that described the magnitude, frequency, duration, timing, and rate of change of water temperature. Results indicate that storage and peaking dams impounding at least 10% of the median annual runoff generally (i) reduced the magnitude of water temperature variation at seasonal, daily, and subdaily timescales and (ii) increased the monthly mean water temperature in September. This regional assessment offers important insight regarding a generalized pattern of thermal alteration by dams, and this information could be used to guide biological monitoring efforts in regulated rivers.

Investigation of the lake-effect on the local thunderstorm activity around the Lake Fertő, Hungary

2020 ◽  
Author(s):  
Gayane Karapetyan ◽  
Veronika Barta
Keyword(s):  
Great Lakes ◽  
Water Temperature ◽  
Air Temperature ◽  
Positive Impact ◽  
Thunderstorm Activity ◽  
Lightning Activity ◽  
Lower Atmosphere ◽  
Distribution Maps ◽  
Negative Effect ◽  
The Impact

<p>Natural and artificial lakes are able to change the climate of their surroundings. These modifications are collectively known as lake effects and range from microscale to synoptic scale. The presence of the lake can cause negative effect on the local thunderstorm activity in summertime decreasing the convection and precipitation over lakes due to the greater stability created by the lower atmosphere and the colder surfaces of the lake [1, 2]. However, it also can have a positive impact on thundercloud generation when the temperature difference between air in 850 mb height and near earth's surface is more than 13 C causing instability in the atmosphere [3].</p><p> </p><p>The main objective of the present study is to investigate the impact of Lake Fertő (Neusiedler See, located in Hungary and Austria) on local thunderstorm activity by applying statistical analysis on meteorological and lightning data and event studies. Data of the Blitzortung lightning location network, local meteorological data (temperature, precipitation) measured at stations around the lake, water temperature measured at Fertőrákos and temperature measured at 850 mb in Vienna station were used for the analysis. The local thunderstorm activity was investigated during summertime (May - September) in 2015, 2016 and 2017. Lightning distribution maps above and around the lake for the investigated period have been determined based on the Blitzortung data.</p><p> </p><p>According to the lightning distribution maps we can not observe any positive impact of the lake on the lightning activity when water temperature was higher than the air temperature around the lake. Furthermore, we can not conclude that there is a clear negative effect of the lake on the lightning activity based on the lightning distribution maps when the air temperature is higher than the water temperature. Nevertheless, there are some months when it seems a clear border between the lightning activity measured above the lake and at the coast (e. g. in June and July 2015, June 2016). The negative effect also seems to appear in some cases of the investigated local individual thunderstorms, namely the thunderstorm activity is larger above the surrounding surface than directly above the lake. This seems to strengthen the hypothesis that "Deep convection is not often formed in summer above the lakes, and existing storms dissipate significantly when moving above the lakes due to the greater stability created by the lower atmosphere and the colder surfaces of the lake" [1].</p><p> </p><p>[1] Lyons, W. A., Some effects of Lake Michigan upon sqall lines and summertime convention. Proc. 9th Conf. Great Lakes Research, Great Lakes Res. Div. Publ. No. 15, University of Michigan, 259–273, 1966</p><p>[2] Scott, R. W., & Huff, F. A. . Impacts of the Great Lakes on Regional Climate Conditions. Journal of Great Lakes Research, 22(4), 845–863., 1996</p><p>[3] Wilson, J. W. : Effect of Lake Ontario on precipitation. Mon. Wea. Rev. 105, 207–214., 1977</p>

scholarly journals Comparison of a deterministic and statistical approach for the prediction of thermal indices in regulated and unregulated river reaches: case study of the Fourchue River (Québec, Canada)

2020 ◽  
Vol 55 (4) ◽  
pp. 394-408
Author(s):  
Laurie Beaupré ◽  
André St-Hilaire ◽  
Anik Daigle ◽  
Normand Bergeron
Keyword(s):  
Statistical Model ◽  
Water Temperature ◽  
Thermal Regime ◽  
Anthropogenic Impacts ◽  
Stressful Events ◽  
Fish Distribution ◽  
Management Tool ◽  
Thermal Indices ◽  
The Impact ◽  
Mean Square Errors

Abstract Water temperature is an important factor modifying fish distribution patterns and community abundance in streams, and this is especially true for salmonids. Knowing that dams often modify the thermal regime of rivers, understanding these changes is of crucial importance for fish habitat management. This study aims to improve knowledge about the impact of dams on the thermal regime of rivers during the summer season and to assess the relative efficiency of two modelling tools used to predict water temperature downstream of dams. A deterministic model (Stream Network Temperature (SNTEMP)) and a statistical model based on a canonical correlation analysis were calibrated on the Fourchue River (St-Alexandre-de-Kamouraska, Québec, Canada) upstream and downstream of a reservoir. SNTEMP was used to simulate mean water temperature time series using meteorological inputs and discharge. The statistical model was used to directly estimate thermal indices (descriptive statistics of the thermal regime). The two models were compared based on their efficiency to estimate thermal indices such as mean and maximum monthly water temperatures and other parameters of importance in the understanding of the distribution and growth of ichthyofauna. Water temperature was monitored at 18 locations in the Fourchue River during the summers of 2011 and 12 locations in 2012 to describe the thermal regime and calibrate the models. The statistical model achieved better results than SNTEMP in estimating most of the thermal indices, especially the mean and maximum daily ranges with root mean square errors of 4.1 and 4.9 °C, respectively, for SNTEMP as compared to 0.5 and 1.1 °C for the leave-one-out validation and 0.6 and 1.4 °C for the split-sample mode for the statistical model. The better performance of the statistical model for metrics related to thermally stressful events for fish makes it more appealing as a management tool for water resources and fisheries managers. However, SNTEMP should be considered when the objective is to investigate the impact of climate change, reservoir operations or other anthropogenic impacts.

scholarly journals Convective Heat Transfer of Spring Meltwater Accelerates Active Layer Phase Change in Tibetan Permafrost Areas

2021 ◽  
Author(s):  
Yi Zhao ◽  
Zhuotong Nan ◽  
Hailong Ji ◽  
Lin Zhao
Keyword(s):  
Heat Transfer ◽  
Soil Temperature ◽  
Convective Heat Transfer ◽  
Active Layer ◽  
Convective Heat ◽  
Thermal Regime ◽  
Transport Processes ◽  
Model Parameters ◽  
Soil Layers ◽  
The Impact

Abstract. Convective heat transfer (CHT) is one of the important processes that controls the near ground surface heat transfer in permafrost areas. However, this process has often not been considered in most permafrost simulation studies and its influence on the freeze-thaw processes of the active layer lacks quantitative investigation. The Simultaneous Heat and Water (SHAW) model is one of the few land surface models in which the CHT process is well incorporated in the soil heat-mass transport processes. We applied the SHAW model to investigate the impacts of CHT on active layer thermal dynamics on the Tanggula station, a typical permafrost site located at the eastern Qinghai-Tibetan Plateau with abundant meteorological and soil temperature/moisture observation data. The 2008–2009 observed hourly data were used to calibrate the model parameters and those of 2010 for validation. A control experiment was carried out to quantify the changes in active layer thermal regime affected by vertical advection of liquid water, consisting of three setups: using (1) the original SHAW model with full consideration of CHT; (2) a modified SHAW model ignoring the CHT due to infiltration from the surface, and (3) a modified SHAW model ignoring complete CHT processes in the system. The impacts of vapor convection are not considered in this experiment. The results show that the CHT events mainly happened during thawing periods when the active layer melted at shallow (0–0.2 m) and middle (0.4–1.3 m) soil depths, and its impact on soil thermal regime at shallow depths was significantly greater in spring melting periods than in summer. The impact was minimal in freezing periods and in deep soil layers. During melting periods, temperatures in the shallow and middle soil depths simulated under the scenario considering CHT were higher by up to 10.0 and 1.5 °C, respectively, than those under the scenarios ignoring CHT. The ending dates of zero-curtain effect were considerably advanced with CHT considered, due to the warming effect of CHT associated with infiltration. However, the opposite cooling effect also existed due to presence of upward liquid fluxes and thermal differences between the soil layers. In some certain period, the advection flow including partial return flow reduced the temperatures in the shallow and middle depths by as much as −5.0 and −1.0 °C, respectively. The overall annual effect of CHT by liquid flux is to increase soil temperature in the active layer and favors thawing of frozen ground at the study site.

scholarly journals Modelling the effect of water diversion projects on renewal capacity in an urban artificial lake in China

2015 ◽  
Vol 17 (6) ◽  
pp. 990-1002 ◽  
Author(s):  
Xueping Gao ◽  
Liping Xu ◽  
Chen Zhang
Keyword(s):  
Water Environment ◽  
Three Dimensional ◽  
Transport Processes ◽  
Water Diversion ◽  
Water Age ◽  
Artificial Lake ◽  
Water Renewal ◽  
Renewal Time ◽  
East Lake ◽  
The Impact

To improve the water environment, manual water diversion projects were scheduled to bring freshwater to an urban artificial lake to dilute and divert pollutants out of the lake. A three-dimensional numerical model was used to study the effect of diversion schemes on the transport of dissolved substances by using concepts of water renewal time and water age. The model results showed that the impact of diversion schemes on transport processes was strongly influenced by hydrodynamic conditions induced by inflow/outflow discharges. Shorter water timescales occupied the west and east lake, implying a faster water renewal occurrence therein. Water ages were highly variable, both spatially and temporally. Longer water age was exhibited in the inner lake and bays. An exchange rate of 89.3% was obtained at the 5 m3/s discharge condition under 60 days' duration, with integral renewal time of approximately 50 days. The distribution of water age showed that it only took less than 10 days for the substance discharged at the inlets to be transported to the outlets. The results offer useful information for understanding the efficiency of water exchange by diversion projects and can be used to estimate the water renewal capacity for environmental assessment purposes.

scholarly journals Effects of the COVID-19 Pandemic on Anti-vascular Endothelial Growth Factor Treatment in China

2020 ◽  
Vol 7 ◽  
Author(s):  
Kai-Bo Yang ◽  
Hao Feng ◽  
Han Zhang
Keyword(s):  
Northern China ◽  
Vascular Endothelial ◽  
Hospital Department ◽  
Anti Vegf ◽  
Treatment Interruptions ◽  
Department Of Ophthalmology ◽  
Negative Effect ◽  
Medical University ◽  
Endothelial Growth Factor ◽  
The Impact

We evaluated the impact of the COVID-19 pandemic on anti-VEGF treatment in ophthalmology patients in a single hospital in northern China. A total of 93 anti-VEGF injections were administered to 85 eyes of 72 patients at The China Medical University First Hospital Department of Ophthalmology during the COVID-19 pandemic. Compared to the same period in 2019, the number of injections decreased by 70%. Fifty-nine eyes of 46 patients were receiving 3+PRN anti-VEGF treatment prior to the outbreak of the COVID-19 pandemic; all of these patients experienced treatment interruptions due to COVID-19-associated reasons. Anatomic and functional outcomes suggest that patients with anti-VEGF treatment interruptions are at risk for severe adverse visual sequelae. Moreover, deferred anti-VEGF treatment due to patient-related or department-related reasons during the COVID-19 pandemic may result in poor visual outcomes for new patients. Our results suggest that COVID-19 has had a significant negative effect on anti-VEGF treatment in ophthalmology patients. Detailed guidance from global experts in ophthalmology is highly sought after in these challenging circumstances.

The Transnational Women's Rights Movement and the World Economy

2020 ◽  
Vol 6 (2) ◽  
pp. 145-173 ◽  
Author(s):  
Heidi E. Rademacher
Keyword(s):  
Women's Rights ◽  
Small Body ◽  
World System ◽  
World Society ◽  
Women’S Rights ◽  
Social Movement Organizations ◽  
Global Movement ◽  
Negative Effect ◽  
Society Perspective ◽  
The Impact

Promoting the ratification of the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW) was a key objective of the transnational women's movement of the 1980s and 1990s. Yet, few studies examine what factors contribute to ratification. The small body of literature on this topic comes from a world-society perspective, which suggests that CEDAW represented a global shift toward women's rights and that ratification increased as international NGOs proliferated. However, this framing fails to consider whether diffusion varies in a stratified world-system. I combine world-society and world-systems approaches, adding to the literature by examining the impact of women's and human rights transnational social movement organizations on CEDAW ratification at varied world-system positions. The findings illustrate the complex strengths and limitations of a global movement, with such organizations having a negative effect on ratification among core nations, a positive effect in the semiperiphery, and no effect among periphery nations. This suggests that the impact of mobilization was neither a universal application of global scripts nor simply representative of the broad domination of core nations, but a complex and diverse result of civil society actors embedded in a politically stratified world.

Linking fish and crustacean taxonomic composition with seasonal contrasts in the soft-bottom intertidal zone

2020 ◽  
Author(s):  
M. A. Gondal ◽  
S. Iqbal ◽  
U. Atique ◽  
N. U. Saher ◽  
N. A. Qureshi ◽  
...  
Keyword(s):  
Species Richness ◽  
Water Temperature ◽  
Fish Species ◽  
Diversity Index ◽  
Taxonomic Composition ◽  
Primary Objective ◽  
Negative Effect ◽  
Fish Species Composition ◽  
One Year ◽  
Sw Monsoon

Abstract The primary objective of this study was to investigate the seasonal fish and crustacean variations concerning taxonomic composition, species richness, and diversity in sandy beach habitat. For this purpose, we investigated the Sonmiani Hor lagoon area during four distinct seasons, i.e., northeast (NE) monsoon, pre-monsoon, south-west (SW) monsoon, and post-monsoon for one year. During each haul, the net was pulled about 100m along the beach in 0.5m depth. The results showed a strong linear correlation between the diversity index and equitability in fishes (r = 0.978). The diversity index was strong negatively correlated with the abundance and biomass (r = -0.978, -0.972, respectively). The physical attributes like sea surface water temperature and salinity showed a strong negative effect on species assemblages (r = -0.981 and -0.943, respectively). The mean air and water temperature illustrated approximately 3°C difference during NE and pre-monsoon seasons. However, salinity, pH, and electrical conductivity did not show any significant seasonal variabilities. Under the ecological indices, the fish species displayed higher diversity (H’ = 3.19) during SW monsoon, whereas the lowest diversity was observed during pre-monsoon (H’ = 1.58). The equitability and species richness, however, remained more noticeable during SW monsoon (J’ = 0.81). The total number of individuals of fish and crustaceans reached 4799 with 3813 fish individuals and 986 individuals of crustaceans. A total of 27 families of fish while five crustacean families comprising of 30 genera and 38 fish species while ten genera and 17 species of crustaceans were recorded. Liza subviridis displayed the highest abundance among the sampled fish species. In conclusion, fish species constituted a significant part of the coastal fauna in the study area. The seasonal variations displayed distinct variations in fish species composition and diversity.

The Impact of Competitive Quasi-Market on Service Delivery in Benue State University, Makurdi Nigeria

GIS Business ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 85-98
Author(s):  
Idoko Peter
Keyword(s):  
Service Delivery ◽  
A Priori ◽  
Least Square ◽  
Secondary Source ◽  
State University ◽  
Ordinary Least Square ◽  
Negative Effect ◽  
The Impact ◽  
The Relationship

This research the impact of competitive quasi market on service delivery in Benue State University, Makurdi Nigeria. Both primary and secondary source of data and information were used for the study and questionnaire was used to extract information from the purposively selected respondents. The population for this study is one hundred and seventy three (173) administrative staff of Benue State University selected at random. The statistical tools employed was the classical ordinary least square (OLS) and the probability value of the estimates was used to tests hypotheses of the study. The result of the study indicates that a positive relationship exist between Competitive quasi marketing in Benue State University, Makurdi Nigeria (CQM) and Transparency in the service delivery (TRSP) and the relationship is statistically significant (p<0.05). Competitive quasi marketing (CQM) has a negative effect on Observe Competence in Benue State University, Makurdi Nigeria (OBCP) and the relationship is not statistically significant (p>0.05). Competitive quasi marketing (CQM) has a positive effect on Innovation in Benue State University, Makurdi Nigeria (INVO) and the relationship is statistically significant (p<0.05) and in line with a priori expectation. This means that a unit increases in Competitive quasi marketing (CQM) will result to a corresponding increase in innovation in Benue State University, Makurdi Nigeria (INVO) by a margin of 22.5%. It was concluded that government monopoly in the provision of certain types of services has greatly affected the quality of service experience in the institution. It was recommended among others that the stakeholders in the market has to be transparent so that the system will be productive to serve the society effectively

Problems of Implementation of an Import Substitution Policy in the Oil Industry

2019 ◽  
pp. 50-57
Author(s):  
Yu. V. Vertakova ◽  
A. S. Evtyukhin
Keyword(s):  
Import Substitution ◽  
Oil Industry ◽  
Investment Climate ◽  
Scientific Publications ◽  
Stage Of Development ◽  
Current Economic Situation ◽  
Negative Effect ◽  
Substitution Policy ◽  
Investment Process ◽  
The Impact

The presented study addresses the issues of implementation of an import substitution policy in the Russian oil industry. Support of domestic production is a key objective specified in the message of the President of the Russian Federation in 2019. In light of the current economic situation and considering the importance of the oil industry for the Russian economy, an import substitution policy could help achieve the objective set by the President.Aim. The study aims to identify the problems and ways of implementation of an import substitution policy in the Russian oil industry.Tasks. The authors analyze scientific publications on import substitution and the state of the Russian oil industry at the current stage of development; determine the directions and fundamental trends in the development of the oil industry; identify obstacles that hinder the implementation of an import substitution policy in the oil industry; describe conditions that facilitate the development of the  investment process in the oil industry; propose comprehensive methods and ways to intensify investments and optimize costs for enterprises in the oil industry.Methods. This study uses general scientific methods of cognition, comparative and statistical analysis to identify problems in the implementation of an import substitution policy in the oil industry.Results. Examination of the current state and development prospects of the oil industry allows the authors to identify obstacles to the development of import substitution. The study shows their impact on the potential of import substitution, which has a negative effect on the prospects of intensification of investment processes, and proposes comprehensive methods and mechanisms that could neutralize the impact of the identified obstacles, thus facilitating the formation of a positive investment climate. Conclusions. Investment climate is shown to have a decisive impact on the potential of import substitution in the Russian oil industry, and ways of overcoming negative trends in the development of the oil industry are proposed.

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