Cm In Winter Research Articles

Tidal Flat Erosion Processes and Their Dynamic Mechanisms on the South Side of Sheyang River Estuary, Jiangsu Province

Tidal flats are accumulations of fine-grained sediment formed under the action of tides and play a very important role in coastal protection. The northern part of Jiangsu coast, as a typical example of muddy coasts found all over the world, has experienced serious erosion since the Yellow River shifted northward, and the range of erosion has been gradually extending southward, now reaching the south of the Sheyang River estuary (SYRE). In order to address coastal erosion near the SYRE through protective measures, there is an urgent need for research on the spatial and temporal variation of coastal erosion processes and their control mechanisms in the SYRE and adjacent coastal areas. For this study, the tidal flats on the south side of the SYRE were selected as the study area, and the sediment dynamics in the upper and lower intertidal flat were observed in different seasons to investigate the erosion processes and their dynamic mechanisms. The results show that the tidal current and wave action in the observed intertidal flats are stronger in winter than in summer, and these intertidal flats erode under the combined action of waves and currents. During winter, the net transport of the near-bottom suspended sediment and bedload is primarily towards the southeast, while in summer, the direction tends toward the north and northeast. The net transport fluxes are larger in the lower part of the intertidal flat than in the upper part in summer and also larger in winter than in summer within the lower intertidal flat. Furthermore, the tidal flat erosion in the study area manifests as shoreline retreat and flat surface erosion. The average shoreline retreat rate increased from 23.3 m/a during 2014–2019 to 43.5 m/a during 2019–2021, and the average erosion depth of the lower and upper parts of the intertidal flat over a tidal cycle is, respectively, 1.98 cm and 0.24 cm in winter and 1.65 cm and 0.26 cm in summer. The ratio of the wave-induced bottom shear stress to the tidal current-induced bottom shear stress is 0.40~0.46 in the lower intertidal flat and increases to 0.66~0.67 in the upper intertidal flat, indicating that the intertidal flat erosion in the study area is primarily driven by tidal currents, with significant contributions from wave action, especially in the upper intertidal flat.

Dynamics of fishery and distribution of aggregations for saffron cod Eleginus gracilis (Tilesius) at northern Kuril Islands

The fishery on winter-spring accumulations of saffron cod in the area of northern Kuril Islands has a long history with varying intensity, though this species is not abundant both in the Pacific and Okhotsk Sea waters of this area. The annual catch ranged from 1.8 to 167.4 t in 2003–2022, on average 40.8 t/yr. The fish with length of 24–56 cm were presented in commercial catches of Danish seine, with prevalence of the 36–48 cm size group. The average length of saffron cod in the catches was changed from 35.4 cm in summer to 43.2 cm in winter that coincided with the fishing depth increasing in winter. The main commercial concentrations of the species had formed between the islands of Paramushir and Shumshu and in the area of the First Kuril Strait.

Effect of Water Transparency on the Growth of Black Tiger Shrimp,<I>Penaeus monodon</I>

The present study was carried out at "Shrimp Culture Pilot Project", Chandipur coast of Orissa, India, during 1995-1996 to study the role of water transparency on water quality and growth of Penaeus monodon under semi-intensive culture system. It was observed that satisfactory range of average daily growth (ADG) of P. monodon achieved when transparency ranged between 29-35 cm in winter and 30-45 cm in summer. Influence of water transparency on various stages of growth was highly significant (P < 0.01) under semi-intensive culture system. Irrespective of stocking density, high growth rate was mostly obtained during 60-100 days of culture when transparency ranged between 37 ± 8 cm. Growth rate was low at high and low transparency probably due to low nutrient content and high organic load with maximum daily fluctuation of pH (>1.0) and dissolved oxygen (8.1-10.6 mg/1), respectively.

Large-scale raceway pond reactor for CEC removal from municipal WWTP effluents by solar photo-Fenton

Continuous flow solar photo-Fenton process has been carried out at demonstration scale at flow rates up to 18 m3 h−1 as an advanced treatment for the removal of contaminants of emerging concern, CECs. A 100-m2 raceway pond reactor, RPR, has been built in the WWTP of Almeria city, Spain. The fluid dynamics study showed plug-flow in the reactor channels and perfect mixing in the bends and paddlewheel sections, giving rise to long mixing times. Consequently, for CEC removal the RPR was operated in continuous flow mode at 1 h of hydraulic residence time and acidic pH, with 0.1 mM FeSO4 and 1.47 mM H2O2. Liquid depth was set at 10 cm in winter and 18 cm in summer, achieving > 85% of CEC removal in both cases. For the first time, CEC removal by solar photo-Fenton has been demonstrated under real operational conditions paving the way for its commercial application.

Mechanistic modeling of solar photo-Fenton with Fe3+-NTA for microcontaminant removal

This work presents, for the first time, a mechanistic model of the solar photo-Fenton process with ferric nitrilotriacetate (Fe3+-NTA), the most cost-effective iron source for microcontaminant removal at neutral pH. The model was developed in three stages, considering the thermal decomposition of Fe3+-NTA, the contribution of temperature on Fenton-like reactions and the effect of the photon absorption of Fe3+-NTA on photochemical reactions. To determine the kinetic parameters, the imidacloprid degradation data (100 µg L−1) obtained at lab scale with 1.47 mM of H2O2 and 0.1 mM of Fe3+-NTA at different temperatures, UVA irradiances and liquid depths were used. The model was successfully validated in raceway pond reactors, changing the scale from 0.84 L to 80 L. According to model predictions, more than 90% of microcontaminant removal could be attained in 30 min operating the photoreactor with liquid depths of 15 cm and 60 cm in winter and summer, respectively.

Seasonal Distribution, Composition, and Inventory of Plastic Debris on the Yugang Park Beach in Zhanjiang Bay, South China Sea.

Plastic debris contamination in marine environments is a global problem that poses a considerable threat to the sustainability and health of coastal ecosystems. Marine beaches, as the key zones where terrestrial plastic debris reach coastal waters, are faced with the increasing pressures of human activities. In this study, we explored the distribution, composition, and inventory of plastic debris over seasonal and tidal zones at the Yugang Park Beach (YPB) in Zhanjiang Bay, South China Sea, to provide a baseline for plastic debris on a marine beach. The results showed mean abundance of plastic debris in summer (6.00 ± 2.10 items/m2) was significantly greater than that in winter (3.75 ± 2.12 items/m2). In addition, the composition of plastic debris ranged in size mainly from 1 to 5 mm and 0.5 to 2.5 cm in winter and summer, respectively. In terms of composition, white plastic debris was the most common (81.1%), and foam was the most abundant (64.4%). Moreover, there was a significant relationship between the abundance of plastic debris and sand grain size fraction (p < 0.05), implying the abundances of microplastic debris were more easily impacted by sand grain size (>2 mm). In total inventory, there were about 1.18 × 105 and 2.95 × 105 items of plastic debris on the YPB in winter and summer, respectively. The tidal variation and human activities are responsible for the plastic debris accumulation. This study provided a method to quantify the inventory of plastic debris on a beach and could be helpful to consider regional tidal variations and critical source areas for effective plastic debris clean-up.

Simulation and analysis of energy consumption in the use of industrial building of wall panel

The energy consumption of industrial building wall panels in the use phase is simulated. The temperature variation and heat transfer of wallboard with different thickness of insulation layer in different climate zones were studied. The results show that the difference of daily average heat transfer is less than 0.01 MJ/M2 for the wall panels with different thickness of insulation layer in the same city in summer. However, the daily average heat transfer among cities is quite different. The daily average heat transfer of Guangzhou wallboard is the largest, which is more than 1 MJ/m2, followed by Beijing. The average daily heat transfer is maintained above 0.69 MJ/m2, and Shanghai’s wallboard has the least average daily heat transfer, only 0.32-0.33 MJ/m2. It can be known from the above data that Beijing needs to choose a composite wall board with a thermal insulation layer thickness of 6 cm in winter, Shanghai uses a composite wall board with a thermal insulation layer thickness of 4 cm, and Harbin chooses a composite wall board with a thermal insulation layer thickness of 6 cm or more to meet the insulation requirements.

Satellite Remote Sensing of Snow Depth on Antarctic Sea Ice: An Inter-Comparison of Two Empirical Approaches

Snow on Antarctic sea ice plays a key role for sea ice physical processes and complicates retrieval of sea ice thickness using altimetry. Current methods of snow depth retrieval are based on satellite microwave radiometry, which perform best for dry, homogeneous snow packs on level sea ice. We introduce an alternative approach based on in-situ measurements of total (sea ice plus snow) freeboard and snow depth, which we use to compute snow depth on sea ice from Ice, Cloud, and land Elevation Satellite (ICESat) total freeboard observations. We compare ICESat snow depth for early winter and spring of the years 2004 through 2006 with the Advanced Scanning Microwave Radiometer aboard EOS (AMSR-E) snow depth product. We find ICESat snow depths agree more closely with ship-based visual and air-borne snow radar observations than AMSR-E snow depths. We obtain average modal and mean ICESat snow depths, which exceed AMSR-E snow depths by 5–10 cm in winter and 10–15 cm in spring. We observe an increase in ICESat snow depth from winter to spring for most Antarctic regions in accordance with ground-based observations, in contrast to AMSR-E snow depths, which we find to stay constant or to decrease. We suggest satellite laser altimetry as an alternative method to derive snow depth on Antarctic sea ice, which is independent of snow physical properties.

Numerical Simulation for the Seasonal Change of the Temperature and Humidity Field of Embankment in Moist Heat Areas

Taking the meteorological data in Fuzhou area in 2011 as an example, this paper investigate the seasonal change of the temperature and humidity field of embankment in moist heat areas based on the finite difference technology programmed Moisture-heat coupled procedure. The results show that the highest temperature in the soil surface of embankment is near 40°C and the highest temperature gradient is up to 0.22°C/cm in summer. The lowest temperature is near 10°C and the highest temperature gradient is up to-0.21°C/cm in winter. Fluctuation range of the water content in the surface of the embankment (0cm~10cm) is between 3% and 20%, and fluctuation range of the water content of the shallow soil layer of embankment (10cm~50cm) is between 10% and 20%, and the water content in the deep layer of embankment (50cm~250cm) changes not apparently with season. If the temperature gradient of soil is 0°C/cm and the yearly fluctuation range of the water content of the embankment is 2%, the temperature and humidity of the embankment that can be affected by the climate of the Fuzhou area is in the depth of about 4.0m and 2.5m respectively.

Forage accumulation in brachiaria grass under continuous grazing with single or variable height during the seasons of the year

The objective of this study was to evaluate grazing management strategies of Brachiaria decumbens cv. Basilisk managed with different heights under continuous grazing with cattle. Two grazing management strategies were evaluated: maintenance of pasture with an average height of 25 cm throughout the experimental period and maintenance of pasture on the average of 15 cm in height during winter, up to 25 cm from the beginning of spring. The split-plot scheme and the randomized block design with four replications were adopted. The grazing management strategies corresponded to the primary factor, while the seasons (winter, spring and summer) corresponded to secondary factor. The reduction of the average sward height to 15 cm in the winter resulted, when compared with pasture maintained at 25 cm, in overall higher growth rates (95 kg/ha.day DM) and leaf blade (66.1 kg/ha.day DM), as well as higher rates of total accumulation (81.5 kg/ha.day DM) and leaf blade (52.6 kg/ha.day DM). The accumulated forage production (from winter to summer) was higher in the pasture lowered to 15 cm in winter (25.6 t/ha DM) compared with that managed with an average height of 25 cm (22.2 t/ha DM). Regarding the seasons of the year, in the winter, there were lower rates of overall growth (6.4 kg/ha.day DM), leaf blade (5.6 kg/ha.day DM) and pseudostem (0.8 kg/ha.day DM), and also lower total (-6.6 kg/ha.day DM) and leaf blade (-7.5 kg/ha.day DM) accumulation rates. In the spring there was a higher rate of leaf senescence (22.4 kg/ha.day DM). The accumulation of forage is incremented when the pasture of B. decumbens is lowered to 15 cm during the winter, and in the spring and summer, its average height is increased to 25 cm.

Capim-braquiária sob lotação contínua e com altura única ou variável durante as estações do ano: dinâmica do perfilhamento

Objetivou-se estabelecer estratégias de manejo do pastejo, sob lotação contínua, que otimizem o padrão natural de perfilhamento da Brachiaria decumbens cv. Basilisk. Duas estratégias de manejo do pastejo foram estudadas: em uma, o pasto foi mantido com 25 cm de altura média durante todo o período experimental; e na outra foi mantido em 15 cm de altura média durante o inverno, com aumento para 25 cm a partir do início da primavera. Adotou-se o esquema de parcelas subdivididas em delineamento em blocos casualizados com quatro repetições. Consideraram-se como fator primário as estratégias de manejo do pastejo, caracterizadas pelas alturas médias em que os pastos foram mantidos durante as estações do ano (inverno, primavera e verão) e, como fator secundário, as medidas ao longo do período experimental. A taxa de aparecimento de perfilho (4,7%), a taxa de mortalidade (4,7%) e o índice de estabilidade (0,998) foram menores no inverno. Nesta estação, contudo, a taxa de sobrevivência de perfilho foi maior (95,3%). Em comparação aos pastos mantidos com 25 cm, aqueles manejados com 15 cm de altura média no inverno apresentaram maiores taxas de aparecimento de perfilho (34,2%) e índice de estabilidade (1,065). O florescimento do capim-braquiária ocorreu apenas no verão e com pouca intensidade (0,5%). A otimização da renovação de perfilhos no pasto de B. decumbens cv. Basilisk sob lotação contínua ocorre com seu rebaixamento para 15 cm no início do inverno e seu posterior aumento para 25 cm no início da primavera.

Número de perfilhos do capim-braquiária em regime de lotação contínua

The study was conducted to identify, through assessments of tillering, appropriate management strategies for Brachiaria decumbens cv. Basilisk under continuous stocking with cattle. Two management strategies were studied: pasture with 25 cm throughout the experimental period, and pasture with 15 cm in winter and 25 cm in spring and summer. A split-plot and randomized block design with four replications were adopted. The management strategies represented the primary factor, and the seasons (winter, spring and summer) were the secondary factor. The lowest balance between rates of appearance (TAR) and mortality (TMR) of tillers and the lowest number of vegetative tillers occurred in winter. In spring and summer, the balance and number of vegetative tillers were higher and did not differ. The lowering of pasture in winter resulted in greater balance between TAR and TMR and higher number of tillers in relation to management on sward fixed at 25 cm. There were greater numbers of reproductive and dead tillers in summer and winter, respectively. The pastures with fixed height of 25 cm contained a higher number of dead tiller. Under continuous stocking, the lowering of B. decumbens pasture in winter and its increase to 25 cm in spring and summer optimizes turnover of tillers.

Numerical Analysis of Passive Capillary Wick Samplers prior to Field Installation

Accurately measuring water fluxes and associated nutrient or contaminant concentrations through the vadose zone is difficult because an appropriate suction needs to be exerted on the soil to sample water under unsaturated conditions. Passive capillary wick sampling systems are cheap and reliable instruments resulting in acceptable measurements of water fluxes in the vadose zone; however, their success in measuring realistic fluxes depends on their compatibility with the soil and climatic conditions in which they are installed. This study was developed in the preplanning phase of a field experiment with its main objective the monitoring of dissolved organic matter and the associated transfer of Cu2+ and pesticides through the vadose zone. We studied a combination of two‐dimensional and axisymmetrical three‐dimensional numerical analyses using the HYDRUS‐2D software to identify what sampler geometry, wick type, wick length, and number of wicks are most suitable for the soil conditions at the experimental site. An AM3/8HI wick with seasonally varying wick length (40 cm in winter and 100 cm in summer) was found to be most appropriate for the soil and climatic conditions of the experimental field. The numerical analysis indicated that well‐designed wick samplers had a negligible effect on the soil moisture content close to the sampler. A double‐ring wick sampler is proposed to minimize the effect of the area between the installation pit or trench and the sampler. This approach is easily applicable and transferable to other soil and wick types and climatic conditions. The study emphasizes the suitability of numerical modeling to optimize experimental design before installation.

Arctic Surface, Cloud, and Radiation Properties Based on the AVHRR Polar Pathfinder Dataset. Part I: Spatial and Temporal Characteristics

Abstract With broad spectral coverage and high spatial and temporal resolutions, satellite sensors can provide the data needed for the analysis of spatial and temporal variations of climate parameters in data-sparse regions such as the Arctic and Antarctic. The newly available Advanced Very High Resolution Radiometer (AVHRR) Polar Pathfinder (APP) dataset was used to retrieve cloud fraction, cloud optical depth, cloud particle phase and size, cloud-top pressure and temperature, surface skin temperature, surface broadband albedo, radiative fluxes, and cloud forcing over the Arctic Ocean and surrounding landmasses for the 18-yr period from 1982 to 1999. In the Arctic, Greenland is the coldest region with the highest surface albedo, while northeastern Russia has the highest surface temperature in summer. Arctic annual mean cloud coverage is about 70%, with the largest cloudiness occurring in September and the lowest cloudiness occurring in April. On annual average, Arctic cloud visible optical depth is about 5–6. Arctic precipitable water is near 0.2 cm in winter and 1.5 cm in summer. The largest downwelling shortwave radiative flux at the surface occurs in June; the largest upwelling shortwave radiative flux occurs in May. The largest downwelling and upwelling longwave radiative fluxes as well as the net all-wave radiative flux occur in July, with the largest loss of longwave radiation from the surface in April.

Results of Year-Round Remotely Sensed Integrated Water Vapor by Ground-Based Microwave Radiometry

Based on two years of measurements with a time resolution of 1 min, some climatological findings on precipitable water vapor (PWV) and cloud liquid water (CLW) in central Europe are given. A weak diurnal cycle is apparent. The mean overall diurnal variation was about 0.15 cm in summer and 0.05 cm in winter, equivalent to 8% and 5%, respectively. The PWV increase starts in summer at about 0800 local time and has a maximum of about 0.02 cm h21 between 1000 and 1500 local time, equivalent to about 1% PWV h21. There was, on average, no PWV variation during the night in winter. PWV decreased in winter during the morning with a maximum of 0.01 cm h21 and increased in the afternoon with a maximum of 0.01 cm h21. Thus, the accuracy of the monthly means of PWV based on monitoring systems with low-time resolution (satellites, radiosondes) is only slightly affected by the diurnal course of PWV in central Europe. On average an increase in PWV and CLW was found in the 30-min interval before precipitation in summer. The PWV increase was, however, only about 0.1 cm or 5% of PWV within the last 2 h before rain. The corresponding CLW increase was 0.1 mm, which is considerable as precipitation was observed when CLW reached 0.3‐0.4 mm.

Annual course of sediment parameters and meiofauna on a sandy tidal flat in the wadden sea after the severe winter of 1995/96

Local abiotic and biotic data are presented from the Groninger Plate (a sandy tidal flat south of Spiekeroog Island) covering a period of one year (February 1996 — February 1997), which includes the coldest part of the ice winter of 1995/96 as well as the winter of 1996/97. The thickness of the visible oxidized layer revealed a clear seasonality. Regarding sandy sediments, values were generally low and ranged between 2.9 cm in winter and 0.9 cm in summer. Biotic and abiotic data are restricted to composition and abundance of meiofauna taxa, total organic carbon, Chl a and phaeopigments as well as temperature and salinity. A significant reduction of meiofaunal abundance, particularly of nematodes, in the top 2 cm was recorded in samples taken in sediments covered by ice, as compared to sediments without an ice cover. However, vertical distribution of meiofauna under ice cover showed that nematodes had migrated to deeper sediment layers. The meiofauna appeared to have overcome the stress of low temperatures and ice formation better than the macrofauna.

Effects of winter cutting management on growth and tiller numbers of six grass species

Abstract Tiller numbers of six grass species grown with ‘Grasslands Huia’ white clover (Trifolium repens L.) increased from early winter 1982 to mid winter, with a small reduction in late winter. Tiller numbers almost doubled in ‘Grasslands Roa’ tall fescue (Festuca arundinacea Schreb.) and ‘Grasslands Maru’ phalaris (Phalaris aquatica L.). Cutting three times in winter gave higher tiller numbers in late August than cutting twice. Maru, Roa, and ‘Grasslands Matua’ prairie grass (Bromus willdenowii Kunth) had the highest winter growth rates; 17, 12, and 13 kg DM/ha per day respectively. ‘Grasslands Nui’ perennial ryegrass (Lolium perenne L.), ‘Grasslands Kahu’ timothy (Phleum pratense L.), and ‘Grasslands Wana’ cocksfoot (Dactylis glomerata L.) had low winter growth rates (< 10 kg DM/ha per day). Kahu had the highest growth in early spring, Matua the slowest. Plots cut twice in winter grew more during winter than plots cut three times, but the reverse occurred in early spring: the possible implications of this in ‘all-grass wintering’ are discussed. In a second trial with pure stands of Nui and Matua only, cutting to 2 cm height gave higher yields than cutting to 4 cm in winter, but the reverse occurred in early spring. Matua outyielded Nui in winter but yields were similar in early spring. Matua also had a higher nitrogen (N) content. Tiller numbers remained unchanged at the three counting dates, possibly a result of a soil N shortage in winter.

Factors affecting the production of biomass by a nitrogen-fixing blue-green alga in outdoor culture

The effectiveness of an aeration-shaking (air-lift) system for outdoor biomass photoproduction by the N 2-fixing filamentous blue-green alga Anabaena variabilis was evaluated and the influence of relevant factors on the productivity of the system was assessed. Air at a flow rate of 60 liters per liter of cell suspension per h was enough, by itself, to promote adequate turbulence and to supply the gaseous nutrients (CO 2 and N 2) needed for maximal productivity. The addition of either or both, CO 2 and combined nitrogen (as KNO 3 or NH 4Cl), did not result in any increase in productivity. In summer and winter, optimal cell density for a suspension depth of 25 cm was 0·2–0·3 g (dry weight) liter −1 and 0·1–0·2 g (dry weight) liter −1 respectively. Reciprocally, optimal suspension depth for a cell density of 0·2 g (dry weight) liter −1 was 20–25 cm in summer and below 15 cm in winter. Optimal values for pH and temperature were 8·2–8·4 and 30–35°C, respectively. Under optimal conditions, mean productivity values were about 13 g (dry weight) m −2 day −1 in summer and 6 g (dry weight) m −2 day −1 in winter. Net protein content of A. variabilis cells was higher than 50%, and nitrogen accounted for 10% of the dry biomass. From the productivity and nitrogen content data, the N 2 fixation rate in outdoor cultures of A. variabilis can be estimated to be higher than 1 g N m −2 day −1, i.e. more than 3 t N per hectare per year when values are extrapolated both in time and area.

Population dynamics and life cycle of Hyale barbicornis (Amphipoda, Crustacea) in a blue mussel zone

Population dynamics and life cycle of Hyale barbicomis Hiwatari & Kajihara from a blue mussel zone were studied in Tokyo Harbor, Japan. Abundance attained a maximum of 3688 individuals 100~ cm in summer and fell to a minimum of 134 indiv. 1002 cm in winter. Temperature is an important factor in regulating abundance. Death rate exceeded birth rate during April and May even though birth rate of overwintering females indicated a high value. This was probably due to newborn juveniles being exposed to low temperature. A high birth rate maintained during summer resulted in a peak in abundance. Females reached maturity at a small size (5 mm) in summer when temperatures were high. On the basis of an in situ growth experiment and size distribution data, the summer population is estimated to live less than 2 mo. Some juveniles born in autumn overwintered as immature females of large size (7 mm). The overwintering population lived about 8 to 9 mo. Brooding females were present throughout the year, with an abundance peak in spring and a high abundance during summer to early autumn. The life cycle probably consisted of at least 3 overlapping generations. Fecundity varied seasonally.

Diurnal changes of radio refraction

Pathlength variations due to refraction changes in the troposphere may impose a severe limitation to VLB experiments (like random clock drifts). In connection with a VLB experiment Moran and Penfield (1976) analysed surface values of water vapor density, data of several hundred radiosonde launches and of measurements of sky brightness near the water vapor line at λ = 1.3 cm. They found that the surface values allow to estimate the pathlength to an accuracy of 5 cm in summer and 2 cm in winter. Sky brightness data give a prediction accuracy of 1.5 cm for all weather conditions, but for cloudfree conditions the accuracy was 0.3 cm.