Reimagining large-scale open-water fisheries governance through adaptive comanagement in hilsa shad sanctuaries

Abstract Background Earlier breeding is one of the strongest responses to global change in birds and is a key factor determining reproductive success. In most studies of climate effects, the focus has been on large-scale environmental indices or temperature averaged over large geographical areas, neglecting that animals are affected by the local conditions in their home ranges. In riverine ecosystems, climate change is altering the flow regime, in addition to changes resulting from the increasing demand for renewable and clean hydropower. Together with increasing temperatures, this can lead to shifts in the time window available for successful breeding of birds associated with the riverine habitat. Here, we investigated specifically how the environmental conditions at the territory level influence timing of breeding in a passerine bird with an aquatic lifestyle, the white-throated dipper Cinclus cinclus. We relate daily river discharge and other important hydrological parameters, to a long-term dataset of breeding phenology (1978–2015) in a natural river system. Results Dippers bred earlier when winter river discharge and groundwater levels in the weeks prior to breeding were high, and when there was little snow in the catchment area. Breeding was also earlier at lower altitudes, although the effect dramatically declined over the period. This suggests that territories at higher altitudes had more open water in winter later in the study period, which permitted early breeding also here. Unexpectedly, the largest effect inducing earlier breeding time was territory river discharge during the winter months and not immediately prior to breeding. The territory river discharge also increased during the study period. Conclusions The observed earlier breeding can thus be interpreted as a response to climate change. Measuring environmental variation at the scale of the territory thus provides detailed information about the interactions between organisms and the abiotic environment.

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Aerosol-cloud-turbulence interactions in well-coupled Arctic boundary layers over open water

10.5194/acp-2021-888 ◽

2021 ◽

Author(s):

Jan Chylik ◽

Dmitry Chechin ◽

Regis Dupuy ◽

Birte S. Kulla ◽

Christof Lüpkes ◽

...

Keyword(s):

Large Scale ◽

Convective Cloud ◽

Open Water ◽

Convective Transport ◽

Cloud Layer ◽

Mixed Phase ◽

State Variables ◽

Strongly Coupled ◽

Main Research ◽

Weather Model

Abstract. Late springtime Arctic mixed-phase convective clouds over open water in the Fram Strait as observed during the recent ACLOUD field campaign are simulated at turbulence-resolving resolutions. The main research objective is to gain more insight into the coupling of these cloud layers to the surface, and into the role played by interactions between aerosol, hydrometeors and turbulence in this process. A composite case is constructed based on data collected by two research aircraft on 18 June 2017. The boundary conditions and large-scale forcings are based on weather model analyses, yielding a simulation that freely equilibrates towards the observed thermodynamic state. The results are evaluated against a variety of independent aircraft measurements. The observed cloud macro- and microphysical structure is well reproduced, consisting of a stratiform cloud layer in mixed-phase fed by surface-driven convective transport in predominantly liquid phase. Comparison to noseboom turbulence measurements suggests that the simulated cloud-surface coupling is realistic. A joint-pdf analysis of relevant state variables is conducted, suggesting that locations where the mixed-phase cloud layer is strongly coupled to the surface by convective updrafts act as hot-spots for invigorated interactions between turbulence, clouds and aerosol. A mixing-line analysis reveals that the turbulent mixing is similar to warm convective cloud regimes, but is accompanied by hydrometeor transitions that are unique for mixed-phase cloud systems. Distinct fingerprints in the joint-pdf diagrams also explain i) the typical ring-like shape of ice mass in the outflow cloud deck, ii) its slightly elevated buoyancy, and iii) an associated local minimum in CCN.

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The Treatment of Shortwave Radiation and Open Water in Large-Scale Models of Sea-Ice Decay

Annals of Glaciology ◽

10.3189/s0260305500008673 ◽

1990 ◽

Vol 14 ◽

pp. 242-246

Author(s):

Donald K. Perovich ◽

Gary A. Maykut

Keyword(s):

Sea Ice ◽

Large Scale ◽

Open Water ◽

Shortwave Radiation ◽

Areal Extent ◽

Time Step ◽

Climate Simulations ◽

Scale Models ◽

Ice Concentration ◽

Ice Pack

Sea ice covering the polar oceans is only a thin veneer whose areal extent can undergo large and rapid variations in response to relatively small changes in thermal forcing. Positive feedback between variations in ice extent and global albedo has the potential to amplify small changes in climate. Particularly difficult to model is the summer decay and retreat of the ice pack which is strongly influenced by shortwave radiation entering the upper ocean through leads (Iw). Most models assume that all of this energy is expended in lateral melting at floe edges. In reality, only a portion of Iw contributes directly to lateral melting, with the remainder going to bottom ablation and warming of the water. This partitioning of Iw affects not only the magnitude, but also the character of the predicted ice decay, reducing the change in ice concentration and enhancing the thinning of the ice and the storage of heat in the water. In this paper we present an analytical model which includes many of these processes and is stable regardless of time step, making it suitable for use in climate simulations.

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E-DATA: A Comprehensive Field Campaign to Investigate Evaporation Enhanced by Advection in the Hyper-Arid Altiplano

Water ◽

10.3390/w12030745 ◽

2020 ◽

Vol 12 (3) ◽

pp. 745 ◽

Cited By ~ 1

Author(s):

Francisco Suárez ◽

Felipe Lobos ◽

Alberto de la Fuente ◽

Jordi Vilà-Guerau de Arellano ◽

Ana Prieto ◽

...

Keyword(s):

Large Scale ◽

Spatial Scales ◽

Open Water ◽

Water Evaporation ◽

Distributed Temperature Sensing ◽

Field Campaign ◽

Spatial And Temporal Scales ◽

Airborne Measurements ◽

Dry Air ◽

Evaporation Dynamics

In the endorheic basins of the Altiplano, water is crucial for sustaining unique ecological habitats. Here, the wetlands act as highly localized evaporative environments, and little is known about the processes that control evaporation. Understanding evaporation in the Altiplano is challenging because these environments are immersed in a complex topography surrounded by desert and are affected by atmospheric circulations at various spatial scales. Also, these environments may be subject to evaporation enhancement events as the result of dry air advection. To better characterize evaporation processes in the Altiplano, the novel Evaporation caused by Dry Air Transport over the Atacama Desert (E-DATA) field campaign was designed and tested at the Salar del Huasco, Chile. The E-DATA combines surface and airborne measurements to understand the evaporation dynamics over heterogeneous surfaces, with the main emphasis on the open water evaporation. The weather and research forecasting model was used for planning the instruments installation strategy to understand how large-scale air flow affects evaporation. Instrumentation deployed included: meteorological stations, eddy covariance systems, scintillometers, radiosondes and an unmanned aerial vehicle, and fiber-optic distributed temperature sensing. Additional water quality and CO2 fluxes measurements were carried out to identify the link between meteorological conditions and the biochemical dynamics of Salar del Huasco. Our first results show that, in the study site, evaporation is driven by processes occurring at multiple spatial and temporal scales and that, even in the case of available water and energy, evaporation is triggered by mechanical turbulence induced by wind.

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Evaporation measurements with an Optical-Microwave Scintillometer system over a Saline lake in the Atacama Desert

10.5194/egusphere-egu2020-6064 ◽

2020 ◽

Author(s):

Felipe Lobos Roco ◽

Oscar Hartogensis ◽

Jordi Vila ◽

Alberto de la Fuente ◽

Francisco Suarez

Keyword(s):

Large Scale ◽

Saline Lake ◽

Regional Scale ◽

Atacama Desert ◽

Open Water ◽

Heat Fluxes ◽

Sudden Increase ◽

Surface Heat Fluxes ◽

Advantages And Disadvantages ◽

Water Outflow

Evaporation is the main water outflow and a key component of the water and surface energy balance in the endorheic basins of the Atacama Desert. This is very localized to confined environments such as saline lakes, wetlands and crop fields. In these environments, the understanding of evaporation is challenging due to the interaction between the large-scale forcing and local scale turbulence over heterogeneous surfaces. Here, the advection of momentum, heat or moisture plays an important role in the enhancement of evaporation. To understand the evaporation dynamics over such environments, we performed a comprehensive 10-days experiment: the E-DATA (Evaporation caused by Dry Air Transport over the Atacama Desert), localized under extreme conditions in the Salar del Huasco saline&#160;lake (22,3&#176;S - 68,8&#176;W - 3790 m a.s.l.), Chile. The measurement strategy was based on spatially distributed high-resolution surface and airborne observations in combination with WRF (Weather Research Forecasting) modeling. The main findings of the experiment show that evaporation is mainly controlled by the lack of turbulence in the morning and by regional-scale forcing in the afternoon, which leads to a sudden increase in mechanical turbulence, therefore in the evaporation flux. &#160;This work compares&#160;two&#160;in-situ&#160;independent measurements of surface heat fluxes over the saline lake, by using an Eddy Covariance (EC) system and an Optical-Microwave Scintillometer (OMS). Our results show in general a good agreement between&#160;EC and OMS measurements of latent (LvE) and sensible (H) heat fluxes over the water surface (R2: 0,90-0,96). During the morning, slight differences are observed between the EC and OMS measurements. However, differences up&#160;to 200 W m-2&#160;are observed in the afternoon for LvE and up&#160;to 20 Wm-2&#160;for H. The first analysis shows that these differences given during the afternoon are likely attributed to Monin-Obukhov stability (MOST) functions, which need to be developed yet for open water surfaces. Moreover, differences in the footprint of both measurement systems together with dramatic wind changes between the morning and afternoon may play a role. Finally, inaccurate bandpass filtering of the raw scintillometer signal may be a factor in the differences between EC and OMS, where we are currently working to refine our results. Our findings highlight the advantages and disadvantages of each measurement method over an open water body and provide a discussion about its performance. &#160;&#160;&#160;

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Who defines the need for fishery reform? Participants, discourses and networks in the reform of the Greenland fishery

Polar Record ◽

10.1017/s0032247414000126 ◽

2014 ◽

Vol 50 (4) ◽

pp. 391-402 ◽

Cited By ~ 3

Author(s):

Rikke Becker Jacobsen ◽

Jesper Raakjær

Keyword(s):

Decision Making ◽

Large Scale ◽

Policy Networks ◽

Small Scale ◽

Policy Network ◽

Informal Networks ◽

Fisheries Governance ◽

Coastal Fisheries ◽

Institutional Learning ◽

Actual Decision

ABSTRACTThis article investigates recent reforms of the Greenland coastal fisheries in order to contribute to the general lessons on reform and policy networks in the context of a changing Arctic stakeholdership. It analyses participation in fisheries governance decision-making by examining the emergence of discourses and policy networks that come to define the very need for reform. A policy network is identified across state ministries, powerful officials, banks and large scale industry that defined the need for fisheries reform within a ‘grand reform’ discourse. But inertia characterised the actual decision-making process as reform according to this ‘grand reform’ discourse was blocked by a combination of small-scale fishers’ informal networks and the power of the parliamentary majority. After a parliamentary shift in power the new government implemented the ‘grand reform’ gradually whilst new patterns of participation and exclusion emerged. In this process, the identities of the participating participants were reinterpreted to fit the new patterns of influence and participation. The article argues that fishery reform does not necessarily start with the collective recognition of a problem in marine resource use and a power-neutral process of institutional learning. Instead, it argues that fishery reform is likely to be the ‘reform of somebody’ and that this ‘somebody’ is itself a changing identity.

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Stochastic model and method of optimization of operating modes groups of artesian wells in water supply systems

Transfer of innovative technologies ◽

10.32347/tit2141.0309 ◽

2021 ◽

pp. 108-110

Author(s):

Andriy Tevyashev ◽

Olga Matvienko ◽

Gleb Nikitenko

Keyword(s):

Water Treatment ◽

Water Supply ◽

Large Scale ◽

Strong Dependence ◽

Mining Industry ◽

Geographical Location ◽

Open Water ◽

Water Supply Systems ◽

Pumping Stations ◽

Artesian Wells

Water supply of large cities is carried out, as a rule, from open reservoirs - lakes, reservoirs, large rivers, ie from sources with significant water reserves. In this case, the water supply scheme includes: pumping stations of the first rise, which take water directly from the water; water treatment system (purification); pumping stations of the second and third rise, pumping clean water over long distances and supplying it to settlements [1]. If the settlement is located in an area where there are no large open water sources, or the geographical location of the settlement allows the use of groundwater, in which case artesian wells are used as a source of water supply. Usually small settlements are supplied with water from artesian wells. Artesian wells are widely used for water supply of villages, industrial water supply, for irrigation (irrigation systems), in the mining industry, to reduce the level of groundwater. The advantage of using artesian wells to supply the population with drinking water is that the water is extracted from great depths and purified using natural filters [2]. Thus, the cost of water treatment is significantly reduced. The disadvantage of using artesian wells is usually low productivity of the well, the strong dependence of water volumes in the well on climatic and weather conditions, depletion of the well as a result of large-scale construction or extraction of natural minerals such as shale gas [3].

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Superhydrophobic drag reduction in turbulent flows: a critical review

Experiments in Fluids ◽

10.1007/s00348-021-03322-4 ◽

2021 ◽

Vol 62 (11) ◽

Author(s):

Hyungmin Park ◽

Chang-Hwan Choi ◽

Chang-Jin Kim

Keyword(s):

Drag Reduction ◽

Turbulent Flows ◽

Large Scale ◽

Water Environment ◽

Experimental Studies ◽

Open Water ◽

Laminar Flows ◽

Turbulent Regime ◽

Frictional Drag ◽

Factors Affecting

AbstractSuperhydrophobic (SHPo) surfaces have been investigated vigorously since around 2000 due in large part to their unique potential for hydrodynamic frictional drag reduction without any energy or material input. The mechanisms and key factors affecting SHPo drag reduction have become relatively well understood for laminar flows by around 2010, as has been reviewed before [Lee et al. Exp Fluids 57:176 (2016)], but the progress for turbulent flows has been rather tortuous. While improved flow tests made positive SHPo drag reduction in fully turbulent flows more regular since around 2010, such a success in a natural, open water environment was reported only in 2020 [Xu et al. Phys Rev Appl 13:034056 (2020b)]. In this article, we review studies from the literature about turbulent flows over SHPo surfaces, with a focus on experimental studies. We summarize the key knowledge obtained, including the drag-reduction mechanism in the turbulent regime, the effect of the surface roughness morphology, and the fate and role of the plastron. This review is aimed to help guide the design and application of SHPo surfaces for drag reduction in the large-scale turbulent flows of field conditions. Graphic abstract

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Trends in the Seaward Extent of Saltmarshes across Europe from Long-Term Satellite Data

Remote Sensing ◽

10.3390/rs11141653 ◽

2019 ◽

Vol 11 (14) ◽

pp. 1653 ◽

Cited By ~ 4

Author(s):

Marieke Liesa Laengner ◽

Koen Siteur ◽

Daphne van der Wal

Keyword(s):

Satellite Data ◽

Large Scale ◽

Open Water ◽

Classification Performance ◽

Environmental Drivers ◽

Decision Tree Classification ◽

Time Period ◽

Long Time ◽

Water Level Variations

Saltmarshes provide crucial functions for flora, fauna, and humankind. Thus far, studies of their dynamics and response to environmental drivers are limited in space and time. Satellite data allow for looking at saltmarshes on a large scale and over a long time period. We developed an unsupervised decision tree classification method to classify satellite images into saltmarsh vegetation, mudflat and open water, integrating additional land cover information. By using consecutive stacks of three years, we considered trends while taking into account water level variations. We used Landsat 5 TM data but found that other satellite data can be used as well. Classification performance for different periods of the Western Scheldt was almost perfect for this site, with overall accuracies above 90% and Kappa coefficients of over 0.85. Sensitivity analysis characterizes the method as being robust. Generated time series for 125 sites across Europe show saltmarsh area changes between 1986 and 2010. The method also worked using a global approach for these sites. We reveal transitions between saltmarsh, mudflat and open water, both at the saltmarsh lower edge and interior, but our method cannot detect changes at the saltmarsh-upland boundary. Resulting trends in saltmarsh dynamics can be coupled to environmental drivers, such as sea level, tidal currents, waves, and sediment availability.

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Understanding Long-Term Changes of Coastal Saltmarshes from Satellite Remote Sensing

10.5194/egusphere-egu2020-2570 ◽

2020 ◽

Author(s):

Marieke Laengner ◽

Daphne van der Wal

Keyword(s):

Satellite Remote Sensing ◽

Large Scale ◽

Open Water ◽

Google Earth ◽

Environmental Drivers ◽

Decision Tree Classification ◽

Tidal Forces ◽

Time Period ◽

Long Time

Saltmarshes are known to be very important coastal ecosystems. They provide crucial functions for flora and fauna, as well as valuable ecosystem services for humankind. Many methods that are used to investigate these ecosystems are limited in space and time. Long time series of global satellite data enable to observe changes in the extent of saltmarshes on a large scale and over a long time period. We developed an unsupervised decision tree classification method in Google Earth Engine that automatically classifies satellite images into saltmarsh vegetation, mudflats, and open water. We applied the method using Landsat 5 TM data between 1985 and 2011. With this, we are able to detect trends in the seaward extent of saltmarshes globally. We reveal transitions between saltmarsh, mudflat and open water. Furthermore, we put saltmarsh habitat changes in a spatial context and couple trends in saltmarsh dynamics to environmental drivers, such as sea level rise, tidal forces, waves, and sediment availability.

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