Periods Of Strong Winds Research Articles

Wave, flow, and suspended sediment dynamics under strong winds on a tidal beach

Tidal beaches are shaped by intense wave-current interactions, leading to dynamic sediment erosion and accretion, which can be further complicated by strong winds. In this study, field observations were conducted on a tidal beach at the junction of Yangtze Estuary and Hangzhou Bay (China), to investigate the dynamics of wave, flow, and suspended sediment under strong winds. Observations were carried out synchronously at two sites on the middle and lower intertidal beach covering 4 semidiurnal tides (52 h) including a ∼20 h-long strong wind period. During the strong wind period, wave motions and flood currents were significantly enhanced, leading to a high combined wave-current bed shear stress (τcw). The wave-induced bed shear stress (τw) greatly exceeded current-induced bed shear stress (τc). Breaking waves generated turbulence at the surface and amplified the near-bed turbulent Reynolds stress (−u′w′‾ and −v′w′‾) at the shallow, middle intertidal beach. The intense hydrodynamics and turbulence kept sediments in suspension and hindered any settling, resulting in net erosion of the intertidal beach. These findings provide valuable insights into the complex interplay among waves, currents, and sediment dynamics under short-duration strong winds on tidal beaches. A key emphasis is placed on the significant role of breaking waves, underscoring the critical importance of their contribution to near-bed turbulence.

Analysis of the Impact of Layout Mode on the Wind Environment of Dormitories in Coastal Universities in Southern Fujian Province

The building wind environment in coastal areas is highly complex and variable, particularly during winter when strong winds prevail. Understanding the influence of winter winds on human comfort and addressing health issues caused by wind noise in human settlements are very valuable research topics. This study focuses on developing strategies to optimize the wind environment in dormitory buildings located in the southern coastal area, where prolonged periods of strong winds have a significant impact. Specifically, we investigated the current wind in the teacher–student dormitory at Jinjiang Campus of Fuzhou University through questionnaire surveys and field measurements. Additionally, computational fluid dynamics (CFD) simulations were employed to evaluate different dormitory layouts. The research results indicate that it is preferable to position the dormitory areas downwind of large-scale buildings, adopt a staggered layout instead of a regular determinant layout to mitigate the narrow tube effect, avoid designing large-scale squares in the center of the dormitory areas, and enclose the dormitory groups with low-level corridors. These findings provide valuable guidance for the optimizing of winter windproof designs of university buildings located in the same climatic zone along the southeast coast.

How do dunes along a desert urban motorway affect the driving safety of sedans? Evidences from long- and short-term monitoring and IDDES

Urban on the edge of deserts usually build motorways in desert areas to fully develop its tourism resources. However, due to the long-term transport effect of wind-sand flow (WSL), the driving safety of sedans might be affected by the erratic dunes next to the desert motorway. Based on this, this study aims to give an idea of how dunes next to desert urban motorways affect the driving safety of sedans. Firstly, the movement law of WSL in desert areas is revealed based on the combination of long- and short-term monitoring methods. After determining the period of strong wind through long-term monitoring, short-term monitoring can be more effective in revealing the movement law of the WSL and the aerodynamic performance of the sedan under the effect of WSL. Afterward, a three-dimensional refined Computational Fluid Dynamics (CFD) dynamic mesh numerical model of WSL-dune-embankment-sedan-air was established based on the mosaic mesh technology. The aerodynamic impact and erosion effects of the WSL on the sedan were investigated. The main results are as follows: 1. Dunes cause varying WSL, with wind speed decreasing to 19–26% on the leeward side and increasing to about 1.35 times at the end. 2. The windward side and front of the sedan experience continuous sand impact, severely eroding the body surface, and posing safety risks. The main contributions of the present study are expected to proposed a cheap simulation scheme based on IDDES (Improved Delayed Detached Eddy Simulation)-DPM (Discrete Phase Model) for WSL-dune-sedan-embankment.

A Study on the Depositional Law of Road Cutting in the Tengger Desert

In this study, the characteristics of wind-blown sand in the hinterland of the Tengger Desert and the regularity of sand deposition in road cutting are studied by combining a field test and numerical simulation. Firstly, the meteorological observation system is used to obtain the long-term monitoring of the Tengger Desert hinterland, and the perennial wind speed, wind direction, and strong wind period are obtained. Then, a three-dimensional ultrasonic anemometer and stepwise sand accumulation instrument are used to measure the transient wind-blown sand velocity and density at the top of the cutting slope, which provide the basis and verification for the numerical simulation. Finally, Fluent software (2020R2) is used to establish two numerical models with and without grading. Based on Euler’s two-fluid theory and fluctuating-wind user-defined functions, the movement of wind-blown sand in the cutting section of the desert hinterland is simulated, and the regularity of sand accumulation in the cutting section is obtained. The main conclusions are as follows: (1) The strong wind period in the hinterland of the Tengger Desert in 2021 mainly occurs from April to August, and the mainstream wind direction is concentrated in the WSW and SW directions. (2) The sand in the hinterland of the Tengger Desert is mainly medium–fine, and the particle size range is mainly concentrated at 0.075–0.250 mm, accounting for 98.2% of the total sand; the curve of the wind-blown sand density with height is oblique and L-shaped. (3) The method of grading excavation is beneficial to reduce the sand accumulation rate on the road’s surface.

High Mobility and Flexibility in the Habitat Use of Early Juvenile Pikeperch (Sander lucioperca) Based on a Mark-Recapture Experiment

Disentangling the role of factors responsible for juvenile fish dispersal is essential to understand the ecology of individual species, setting the corresponding conservation status and evaluating the potential risk in case of invasion. Because of their small body size and high sensitivity to environmental conditions, juvenile fish movements have largely been explained by external factors such as wind-induced water currents. In this study, early hatched pikeperch (Sander lucioperca) of hatchery origin were marked with oxytetracycline hydrochloride, stocked into a bay near the dam of a deep reservoir, and then monitored at approximately 10-day intervals using fix-frame trawling for 43 and 51 days after stocking, in 2007 and 2008, respectively. In both years, marked pikeperch were captured throughout the study period in the bay and closed dam section of the reservoir. After one month, individuals were captured in the middle section of the reservoir, approximately 5 km upstream from the stocking site. Four individuals were recaptured in the tributary section of the reservoir, about 10 km upstream from the stocking site during the last sampling in 2007. The farthest distance detection followed periods of strong wind. During daytime sampling, marked pikeperch were captured in both the warm epipelagic layer above the thermocline and the cold bathypelagic layer below the thermocline. The later sampling represented a community of vertically migrating individuals originally thought to consist only of reservoir-born and reservoir-experienced fish. This study suggested the high mobility and flexibility of 0+ pikeperch, as well as their unexpected behavioral plasticity.

Erosion and accretion of salt marsh in extremely shallow water stages

Salt marshes, which commonly exist on the upper tidal flat, provide a natural barrier against sea level rise and coastal storm. The extremely shallow water stages (water depth< 0.2 m), including the initial stage of flood tides and the last stage of ebb tides, can induce a significant impact on sediment dynamics of saltmarshes and associated tidal flats, despite lasting for only a short time (around 10 min), which has been less studied. In this study, two parallel field sites were established to quantify erosion-accretion processes and morphological changes during extremely shallow water stages in salt marshes within Doulonggang tidal flat along the Jiangsu coast. Our results revealed that obvious accretion occurred during extremely shallow water stages, with a total deposition amount of +33.8 mm in vegetated areas and +20.8 mm in unvegetated areas. In contrast, erosion dominated during deep water stages, with a total erosion amount of -22.3 mm at the vegetated site and -32.7 mm at the unvegetated site. The magnitude of bed-level change during extremely shallow water stages was 7~8 times greater than that during deep water stages, even though the duration of extremely shallow water stages was only about 14~15% of the entire tidal cycle. Furthermore, strong winds significantly impacted deposition during extremely shallow water stages compared to calm weather. During the strong wind period, the average bed level change rate reached +0.15 mm/min and +0.12 mm/min in the vegetated and unvegetated areas, respectively. This is significantly higher than the +0.05 mm/min and +0.01 mm/min during the calm weather period. These results reveal that extremely shallow water stages have substantial impacts on sedimentary processes, which are vital for the maintenance of tidal flat systems.

Winter and summer sedimentary dynamic process observations in the sea area off Qinhuangdao in the Bohai Sea, China

Sedimentary processes in marginal seas play an important role in the biology, physics, and geochemistry as well as ecology of coastal environments and contain abundant information about the material transfer from land to ocean and the regional circulation. Due to the huge sediment discharge of the Yellow River, the Bohai Sea, China is one of the areas with the highest suspended sediment concentration (SSC) in the world. Interestingly, the SSC at the west of the Bohai Sea is low all year round. Thus, it is of great significance to examine the sedimentary dynamic process in this area for better understanding the circulation structure, material exchange and regional environment of the Bohai Sea. Using seabed base observation platform measurements obtained in February 2017 and August 2019, this study examines the winter and summer hydrography and suspended sediment concentration in the sea area off Qinhuangdao located to the west of the Bohai Sea. In summer, the relatively weak residual currents flowed northeastward and showed little correlation with the wind field, especially in the middle layer of the water column. In winter, the residual currents were strengthened, flowing to the northeast during strong wind periods, and predominantly to the southwest during intermittent periods. Moreover, driven by the pressure gradient force associated with the wind-induced sea surface height variations, the winter current was closely related to the wind speed, with correlation coefficients ranging from 0.4 to 0.6 and a time lag of 10 h. The summer SSC was lower and mainly controlled by the tidal current, whereas in winter, owing to the enhanced Reynolds stress and turbulent kinetic energy, strong wind bursts triggered significant sediment resuspension and led to a higher SSC. For the suspended sediment flux (SSF), the advection terms contributed more than 80% in the winter and summer, while the vertical circulation terms contributed 13% in winter, and approximately half that much in summer. Generally, the suspended sediment is transported back and forth, with a little net northward and northeastward motions in winter and summer, respectively. This may explain the low SSC sustaining in coastal Qinhuangdao all year round. These results provide a reference for sedimentary studies conducted in other coastal waters, especially in monsoon-dominating shelf seas.

Wake dynamic characteristics of windproof structures in embankment–bridge sections along a high-speed railway under natural strong crosswinds

A recent trend in railway development around the world is the extension of high-speed railways to areas with harsh climatic environments. The aerodynamic performance of high-speed trains deteriorates when they run through embankment–bridge sections in a windy environment, posing potential safety risks. The present study aims to reveal the evolution mechanism of wake field in the transition section of the windbreak wall and wind barrier under natural strong crosswinds. First, the fluctuating characteristics of natural wind field collected by ultrasonic anemometers during a period of strong wind are captured. Next, the improved delayed detached eddy simulation scheme combined with the shear stress transfer k–w model is used to elucidate the difference of flow field modes on the leeward side of the windproof structure in the transition section under the conditions of constant and fluctuating crosswinds. Finally, the effects of model scale ratio (1:20, 1:10, and 1:1) on wind field simulation results on the leeward side of the windproof structure are revealed. Results show that the incoming flow with time-varying velocity evokes the instability of wake vortices of the windbreak wall in the embankment. The transient evolution results of the vortices obtained by the 1:10 model are in good agreement with those of the 1:1 model, whereas the results obtained by the 1:20 model have a large deviation.

Net suspended sediment transport modulated by multiple flood-ebb asymmetries in the progressive tidal wave dominated and partially stratified Changjiang Estuary

In many estuaries, current velocity, suspended sediment concentration (SSC), and water depth have notable flood-ebb asymmetries in magnitude or duration. Such asymmetries can make marked impact on estuarine sediment transport and require in-depth analysis of the underlying mechanism. Based on field measurement over a neap-spring cycle in the Changjiang Estuary in January 2015, net suspended sediment transport modulated by multiple asymmetries were analyzed. The results showed that there were notable flood-ebb asymmetries in the current velocity, current duration, SSC, and water depth. The former two were ebb-dominated, while the latter two were flood-dominated. The net suspended sediment transport was landward and exhibited remarkable tidal fluctuation in magnitude. Ebb-dominated velocity and duration asymmetries favored seaward transport, but flood-dominated SSC and water depth asymmetries promoted landward transport. The relative contribution of these asymmetries to the net sediment transport was different and closely related to their asymmetry intensities. The magnitude of net sediment transport was highly modulated by the combined effects of these asymmetries. Further analyses revealed that the ebb-dominated asymmetries in velocity and duration were controlled by river flow, tidal wave deformation, and compensation flow of Stokes drift. The flood-dominated water depth asymmetry was related to the progressive tidal wave. The flood-dominated SSC asymmetry was mainly attributed to the lower SSCs in early ebbs, notable sediment supply limitation in late ebbs, wind wave height asymmetry, and gravitational circulation. Additionally, it is worth noting that the progressive tidal wave can yield strong current asymmetry, notable water depth asymmetry, and obvious wind wave height asymmetry during strong wind periods.

Hydrographic variability in the Gulf of Papagayo, Costa Rica during 2017-2019

Introduction: The Gulf of Papagayo (GP) is a site of socioeconomic importance located in the North Pacific of Costa Rica. The ecosystem services of this site represent a benefit in local communities, and its dynamics are influenced by a coastal upwelling system that affects fishing and commercial activity.
 Objective: The objective of this study was to characterize the spatio-temporal variability of the main hydrographic parameters through measurements in situ during the period 2017-2019.
 Methods: Eight measurement campaigns were carried out, where a CTD probe was deployed to perform vertical profiles in 23 stations distributed throughout the GP, to characterize the variations in temperature, salinity, dissolved oxygen and chlorophyll concentration.
 Results: A minimum in surface and bottom temperature associated with upwelling caused by the wind was found in the first period of the year. The increase in salinity was associated with the decrease in temperature, being its highest value in the first period of the year, decreasing until reaching a minimum in November. The maximum chlorophyll concentration ​​coincided with the lowest surface temperatures and the minimum oxygen values were associated ​​with the minimum bottom temperatures, both occurring during the upwelling season. The parameter distribution was similar on dry and rainy seasons in stations located inside Bahía Culebra, likely attributed to the bathymetry effect.
 Conclusions: Bathymetry determines a south-north asymmetry for salinity and temperature. Subsurface cooling events coincide with strong wind periods. Upwelling influences the surface and bottom hydrographic dynamic in GP and determines the seasonal variability. The negative ENSO phase of 2018 corresponded with the strongest upwelling period, possibly promoting the interaction of upwelled coastal waters and the Costa Rica Thermal Dome.

High-resolution portable-OSL analysis of Vegetated Linear Dune construction in the margins of the northwestern Negev dunefield (Israel) during the late Quaternary

Abstract Vegetated Linear Dunes (VLDs) are elongated dunes whose construction is controlled by vegetation and wind. Common in southern hemisphere drylands, they were mainly active in the late Pleistocene. VLDs vertically accumulate sand during elongation episodes and their internal stratigraphy thus serves as a proxy for major periods of strong winds. However, the framework of VLD buildup and elongation is constrained by low-resolution luminescence chronology. To overcome this gap this study applies high-resolution Portable Optically Stimulated Luminescence (POSL) profiling coupled with OSL dating and sedimentology of an exposed VLD section, combined with successive sections along a fluvially truncated downwind elongation trace of the dune at the margin of the stabilized northwestern Negev dunefield, Israel. POSL profiling of the VLD section revealed three statistically distinct stratigraphic units. Winnowing of very fine sand and silt grains can explain a higher ratio between quartz and heavy minerals in the upper VLD unit. This winnowing decreased dose rates and, consequently, reduced bulk POSL luminescence signals and De values in the upper unit. The two upper units of the VLD section date to the Younger Dryas while the basal unit dates to the Heinrich-1 event. OSL ages at the lower unit and at the section bases along the downwind elongation trace of the dune indicate initial elongation during the Heinrich-1 event, and even prior. The study demonstrates that beyond delineating accumulation stages and assigning stratigraphic units, POSL is a sensitive sensor of sedimentological and mineralogical differences within a dune profile, enabling correlation with OSL measurements.

Surface CO2 system dynamics in the Gulf of Anadyr during the open water season

The Gulf of Anadyr (GA), one of the largest and most poorly investigated gulfs of the Bering Sea, is an important part of the Pacific Arctic. Drivers and mechanisms responsible for the spatial variations in surface seawater CO2 system parameters and associated air–sea CO2 fluxes were investigated during three oceanographic cruises conducted in the GA during the open water season of 1992, 2002, and 2011. It was shown that the surface waters of the GA were moderate to strong sinks for atmospheric CO2 during this season: mean air-sea CO2 fluxes for the investigated areas of the GA, for the three cruises, were −31, −15, and −30 mmol CO2 m−2 d−1, respectively. The summer air-sea CO2 flux was attributed to intensive phytoplankton bloom, and fall CO2 uptake coincided with a period of strong winds and seasonal enhanced primary production. The surface waters of the GA were supersaturated with respect to aragonite during the investigated period. Anadyr Strait, a region of high hydrodynamic activity, was the only area where CO2 efflux was observed. Surface waters of the strait were supersaturated with respect to CO2 and in quasi-equilibrium with respect to aragonite. We found that during the late summer/fall season, the Anadyr Current exported a well-mixed, relatively cold, salty, nutrient- and CO2-rich water through the western Anadyr Strait into the Chirikov Basin. Our research highlights the need for mesoscale studies of the western Bering Sea to produce the most accurate assessment of the regional CO2 budget.

Field investigation of bedform morphodynamics under combined flow

Fieldwork was conducted at the Red Cliff sandbar located in the upper Humber Estuary in order to investigate bedform dynamics under different hydrodynamic conditions related to combinations in tidal and wave-generated currents. A fixed mooring was deployed to obtain current flow and wave properties across the sand bar site at both spring and neap tidal flows and during conditions of high wind generated waves. A terrestrial laser scanner was used to scan the sandbar during low water across the various forcing conditions, acquiring detailed information of ripple geometries. Under spring tide and calm wave conditions, two-dimensional asymmetrical ripples with straight crest lines were generated on the sandbar. Surveys were also conducted during strong winds. Prior to high-wind-waves, two-dimensional symmetrical and washed-out ripples were observed, during spring and neap tidal conditions respectively. The lengths of these ripples were almost the same as those generated under current only conditions, but their heights were relatively smaller. After the strong wind periods, 2D current-induced ripples were replaced by flatbed conditions and 2D symmetrical wash-out ripples, which indicates wave-induced bed shear stress is enhanced by the presence of a tidal current. Most pertinently our study reveals discrepancies between field observations and existing predictions of bed configurations that are largely based on laboratory investigations. This is likely due to a larger grain size distribution in field conditions and due to turbulence dampening by high concentrations of suspended clay particles. The study thus highlights a need to extend a range of field investigations that explore the current deficiencies in our abilities to predict bedforms and bedform dynamics in estuarine systems.

Dynamics of the North Balearic Front during an autumn tramontane and mistral storm: air–sea coupling processes and stratification budget diagnostic

Abstract. The North Balearic Front forms the southern branch of the cyclonic gyre in the northwestern Mediterranean Sea. Its dynamics exhibit significant seasonal variability. During autumn, the front spreads northward during the calm wind periods and rapidly moves back southward when it is exposed to strong northerly wind events such as the tramontane and mistral. These strong winds considerably enhance the air–sea exchanges. To investigate the role of air–sea exchanges in the dynamics of the North Balearic front, we used observations and a high-resolution air–sea coupled modelling system. We focused on a strong-wind event observed in late October 2012, which was well-documented during the Hydrological Cycle Mediterranean Experiment. The coupled model was able to correctly reproduce the 4 ∘C sea surface temperature drop recorded in the frontal zone together with the observed southwestward displacement of the front. The comparison between the weak wind period preceding the event and the strong-wind event itself highlighted the impact of the wind regime on the air–sea coupling. During the low-wind period the coupling is thermal and dynamical whereas during the strong-wind period the coupling is mainly thermal. The effect of air–sea exchanges on the stratification variations in the frontal zone was investigated with a stratification budget diagnosis. The stratification variations are controlled by diabatic air–sea buoyancy flux, adiabatic Ekman buoyancy flux, and advective processes. During the strong-wind period, the Ekman buoyancy flux was found to be 3 times greater than the air–sea buoyancy flux and thus played a major role in the de-stratification of the frontal zone. The role of Ekman pumping and inertial wave in the advective processes is also discussed.

Underwater Sound Sources and Ambient Noise in Fowlers Bay, South Australia, during the Austral Winter

Passive acoustic recordings made in Fowlers Bay, South Australia, during the austral winter of 2013–2017 revealed the presence of several sources of underwater sound. Sound sources of biological origin include baleen and toothed whales, fish and shrimp. Physical sources of underwater sound include wind- and rain-driven noises, and underwater sounds of anthropogenic origin were primarily from boats and occasionally from an aircraft. Biological sound sources were commonly recorded within the frequency range of around 25 Hz to nearly 17 kHz, with baleen whales within the range of ~ 25 Hz to 6 kHz, and dolphins at higher frequencies of approximately 2.5–17 kHz. Broadband sounds from physical and anthropogenic sound sources were noticeable at frequencies above ~ 50 Hz. The ambient noise level in Fowlers Bay at frequencies below 100 Hz was relatively low (around 75 dB re 1 µPa2/Hz for the 95% percentile) due to an insignificant contribution of noise from distant shipping. At higher frequencies, the noise level was governed primarily by noise from wind and varied by nearly 30 dB re 1 µPa2/Hz depending on weather conditions, up to around 80 dB re 1 µPa2/Hz for the 95% percentile during periods of strong winds and intense rainfall.

On Wind Forces in the Forest-Edge Region During Extreme-Gust Passages and Their Implications for Damage Patterns

A damage pattern that is occasionally found after a period of strong winds shows an area of damaged trees inside a forest stand behind an intact stripe of trees directly at the windward edge. In an effort to understand the mechanism leading to this damage pattern, wind loading in the forest-edge region during passages of extreme gusts with different characteristics are investigated using a scaled forest model in the wind tunnel. The interaction of a transient extreme gust with the stationary atmospheric boundary layer (ABL) as a background flow at the forest edge leads to the formation of a vortex at the top of the canopy. This vortex intensifies when travelling downstream and subsequently deflects high-momentum air from above the canopy downwards resulting in increased wind loading on the tree crowns. Under such conditions, the decrease in wind loading in the streamwise direction can be relatively weak compared to stationary ABL approach flows. The resistance of trees with streamwise distance from the forest edge, however, is the result of adaptive growth to wind loading under stationary flow conditions and shows a rapid decline within two to three tree heights behind the windward edge. For some of the extreme gusts realized, an exceedance of the wind loading over the resistance of the trees is found at approximately three tree heights behind the forest edge, suggesting that the damage pattern described above can be caused by the interaction of a transient extreme gust with the stationary ABL flow.

Possible role of power-to-heat and power-to-gas as flexible loads in German medium voltage networks

Germany’s energy transition triggered a rapid and unilateral growth of renewable energy sources (RES) in the electricity sector. With increasing shares of intermittent RES, overcapacities during periods of strong wind and photovoltaic electricity generation occur. In the face of insufficient transmission capacities, due to an inhibited network extension, the electricity generation has to be curtailed. This curtailment of RES leads to economic losses and could be avoided through flexible loads. As an option to cope with those problems, the technologies of power-to-gas (PtG) and power-to-heat (PtH) are presented in this paper. First, the alkaline electrolyzer (AEL), polymer electrolyte membrane electrolyzer (PEMEL), and solid oxide electrolyzer cell (SOEC) are investigated regarding their operational parameters. Second, the electric boiler, electrode heating boiler, and heat pumps are considered. Ultimately, the network-supporting abilities and the potential to provide ancillary services, such as control power, load sequence operation, cold start and part load capability, are compared among one another.

Will hypolimnetic waters become anoxic in all deep tropical lakes?

To elucidate trends of hypolimnetic oxygen concentrations, vertical distributions of dissolved oxygen were measured in eight deep tropical bodies of water (one natural lake with two basins, five natural lakes, and one reservoir) in Indonesia. A comparison of those concentrations with previously reported data revealed that shoaling of hypolimnetic oxygen-deficient (around a few decimeters to a few meter per year) water had occurred in all of the lakes. Calculated areal hypolimnetic oxygen depletion rates were 0.046–5.9 g m−2 y−1. The oligomictic or meromictic characteristics of the bodies of water suppressed circulation and mixing in the hypolimnions and thus resulted in continuous shoaling of the uppermost oxygen-deficient layers. In some lakes, millions of fish sometimes died suddenly, probably owing to upward movement of oxygen-deficient water to near the surface during periods of strong winds. In the future, the rate of shoaling will be accelerated by human impacts in the basins and by climate warming, the influence of which has already been manifested by rising water temperatures in these lakes. Appropriate monitoring and discussions of future restoration challenges are urgently needed to prevent the hypolimnions of the lakes from becoming completely anoxic.

Estimation of efficiency of the heat supply system based on a boiler house and a wind turbine in the northern environment

This article describes a methodological approach to defining indoor air temperature in buildings heated by a power supply unit consisting of a boiler house and a wind-driven power plant (WDPP). We discuss a heating option for a residential building in the windy conditions of Murmansk city. We proved that, during the periods of strong wind, a WDPP can partially or fully satisfy the heat demand and sometimes even create a surplus of energy. During low wind weather, almost all loads are handled by the boiler house. We considered a possibility to accumulate the surplus energy obtained from a WDPP during strong wind by increasing the temperature in the whole building up to 25°C and further using the accumulated heat during the lowwind period when indoor air temperature may fall below 20°C. This allows saving organic fuel in the boiler house. We demonstrated how indoor air temperature in the building may change throughout the year when using the surplus energy from the WDPP due to thermal storage capacitance of the building. We also provided the results of study, showing favorable energy-related effects of using a WDPP along with the boiler house. It was determined that engaging a WDPP in fulfilling the diagram of heating loads promotes the decrease in the boiler house’s contribution to heat supply by 30 to 50%, and using the surplus energy from the WDPP and thermal storage capacitance of the building allows reducing the contribution of the boiler house by 5–15% more in certain months.

A study on the wind erosion potential of agricultural lands after crop harvesting (Case study: Damghan Region)

Aeolian process and subsequently soil erosion are key factors in dryland environments. Such phenomena are related not only to geoecological factors (lithology, topography, and climatology) but also to land-use and plant cover changes. Formation of new sand dunes in Damghan explains the development of human activities over the past. The aim of this study is to explain the land use changes and their contributions and impacts on Aeolian sediments in Damghan Region. The study was carried out using topographic and geologic maps, satellite imagery, aerial photographs, meteorological data, field observation and samplings. According to meteorological data, period of strong winds (May to Jun) were identified. This period is wind activity period. So, based on this period, unprotected soil surface by crop residues with the interpretation of satellite images was determined. The field samples were carried out from May to June 2008 when the wind was active. The study methods include sieving soil granulometry, and analyzing the particle size. Granulometric analyses were performed using conventional dry sieve method. The results of statistical analysis of grain size distribution showed that the mean and median of particle size were composed of coarse and very coarse sand particles. The study indicated that 90% of the agricultural lands contained more than 23% soil aggregates, where in areas with sensitive particles to erosion the Figure was 35%. It can be argued that agricultural land in study area are resistant to wind erosion.