To see the other types of publications on this topic, follow the link: Cold source station.
Journal articles on the topic 'Cold source station'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Cold source station.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Li, Bi, and Shi Zheng. "Application research of intelligent monitoring system of longsheng hot spring water temperature based on Internet of Things." Thermal Science 23, no. 5 Part A (2019): 2613–22. http://dx.doi.org/10.2298/tsci181127150l.
Full textAbstract:
Guangxi Guilin area, China, is rich in hot spring resources. In this paper, a hot spring water temperature monitoring system is developed for longsheng hot springs. Mainly using the hot water of eye of hot springs as the heat source, designing a set of multi-point temperature monitoring system with single-chip and multi-slave as the core of the single-chip microcomputer and wireless and bi-directional transmission for the main station and multiple slave stations to realize automatic temperature monitoring. The system slave station can exchange geothermal water with high temperature extracted from the eye of hot springs and cold water, and automatically control the temperature of the hot spring pool to reach a set value range by controlling the flow rate of the cold water. At the same time, the main station can complete the tasks of monitoring system by setting control commands such as temperature.
2
Santoro, V., K. H. Andersen, D. D. DiJulio, E. B. Klinkby, T. M. Miller, D. Milstead, G. Muhrer, et al. "Development of high intensity neutron source at the European Spallation Source." Journal of Neutron Research 22, no. 2-3 (October 20, 2020): 209–19. http://dx.doi.org/10.3233/jnr-200159.
Full textAbstract:
The European Spallation Source being constructed in Lund, Sweden will provide the user community with a neutron source of unprecedented brightness. By 2025, a suite of 15 instruments will be served by a high-brightness moderator system placed above the spallation target. The ESS infrastructure, consisting of the proton linac, the target station, and the instrument halls, allows for implementation of a second source below the spallation target. We propose to develop a second neutron source with a high-intensity moderator able to (1) deliver a larger total cold neutron flux, (2) provide high intensities at longer wavelengths in the spectral regions of Cold (4–10 Å), Very Cold (10–40 Å), and Ultra Cold (several 100 Å) neutrons, as opposed to Thermal and Cold neutrons delivered by the top moderator. Offering both unprecedented brilliance, flux, and spectral range in a single facility, this upgrade will make ESS the most versatile neutron source in the world and will further strengthen the leadership of Europe in neutron science. The new source will boost several areas of condensed matter research such as imaging and spin-echo, and will provide outstanding opportunities in fundamental physics investigations of the laws of nature at a precision unattainable anywhere else. At the heart of the proposed system is a volumetric liquid deuterium moderator. Based on proven technology, its performance will be optimized in a detailed engineering study. This moderator will be complemented by secondary sources to provide intense beams of Very- and Ultra-Cold Neutrons.
3
Zheng, Xuejing, Qihang Sun, Xueqing Yang, Huzhen Liu, Fangshu Hu, and Leizhai Sun. "Simulation and Analysis of Building Energy Consumption in Port passenger Stations." E3S Web of Conferences 272 (2021): 01011. http://dx.doi.org/10.1051/e3sconf/202127201011.
Full textAbstract:
Port passenger station buildings (PPSD) are an important part of transportation buildings in China, which is characterized by large human flow, long operating time, high load of equipment and lighting. The characteristics and functions of PPSD lead to the high energy consumption. However, the energy consumption analysis of PPSD was deficient. In this paper, the characteristics of energy consumption of port passenger stations in cold regions and hot summer and warm winter regions in China were analyzed. Based on eQUEST, the building models of port passenger stations are established. The influencing factors of the building energy consumption were analyzed through orthogonal experiment with SPSS. Results show that the factors such as summer indoor design temperature, heat source form, air conditioning form, window to wall ratio and lighting control mode are the key factors affecting the energy consumption of port passenger station.
4
Gallmeier, F. X., T. Hügle, E. B. Iverson, W. Lu, and I. Remec. "Options for a very cold neutron source for the second target station at SNS." Journal of Physics: Conference Series 1021 (May 2018): 012083. http://dx.doi.org/10.1088/1742-6596/1021/1/012083.
Full text
5
Zhao, Chun Lei, Jun Hong Fan, Hang Yu Dong, and Jiang Hao Li. "A Method Based on Remote Sensing to Look for Grey Haze Emission Source Area." Applied Mechanics and Materials 556-562 (May 2014): 950–55. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.950.
Full textAbstract:
In this study, we try to find the possible emission source area of the grey haze through comparing the ground observation station weather data and remote sensing data for the grey haze process that Beijing-Tianjin-Hebei region experienced in November the 8-14, 2013 in which the degree of contamination range from severe to mild to severe. The result demonstrates that before the invasion of the cold air , the coverage of the grey haze reach its maximum where south central areas of Beijing-Tianjin-Hebei is more severer compared with the south central and peri-urban areas of Hebei province. For the greater intensity grey haze companied by the wind convergence in the surface boundary layer, the result of the MODIS satellite monitoring is consistent with the meteorological station observation. Whereas MODIS satellite monitoring method could make up the shortfall of the meteorological station for the mild grey haze in certain degree. After the cold air, haze primary development area is very obvious, and the starting position of haze in the role of diffusion by the wind is also here, based on this can lock the grey haze emission source area and make concrete origination by using the high resolution satellite. The precise positioning could provide the scientific basis for the pertinent management on pollution control for the local government and relevant authority.
6
Tang, Qiuhong, Andrew W. Wood, and Dennis P. Lettenmaier. "Real-Time Precipitation Estimation Based on Index Station Percentiles*." Journal of Hydrometeorology 10, no. 1 (February 1, 2009): 266–77. http://dx.doi.org/10.1175/2008jhm1017.1.
Full textAbstract:
Abstract Operational hydrologic models are typically calibrated using meteorological inputs derived from retrospective station data that are commonly not available in real time. Inconsistencies between the calibration and (generally sparser) real-time station datasets can be a source of bias, which can be addressed by expressing real-time hydrological model forcings (primarily precipitation) as percentiles for a set of index stations that report both in real time and during the retrospective calibration period, and by using the real-time percentiles to create adjusted precipitation forcings. Although hydrological model precipitation forcings typically are required at time steps of one day or shorter, percentiles can be calculated for longer averaging periods to reduce the percentile estimation errors. The authors propose an index station percentile method (ISPM) to estimate precipitation at the models input time step using percentiles, relative to a climatological period, for a set of index stations that report in real time. In general, this approach is most appropriate to situations in which the spatial correlation of precipitation is high, such as cold season rainfall in the western United States. The authors evaluate the ISPM approach, including performance sensitivity to the choice of percentile estimation period length, using the Klamath River basin, Oregon, as a case study. Relative to orographically adjusted interpolation of the real-time index station values, ISPM gives better estimates of precipitation throughout the basin. The authors find that ISPM performs best for percentile estimation periods longer than 10 days, with diminishing returns for averaging periods longer than 30 days. They also evaluate the performance of ISPM for a reduced station scenario and find that performance is relatively stable, relative to the competing methods, as the number of real-time stations diminishes.
7
Farrell, W. E., J. Berger, J. R. Bidlot, M. Dzieciuch, W. Munk, R. A. Stephen, and P. F. Worcester. "Wind Sea behind a Cold Front and Deep Ocean Acoustics." Journal of Physical Oceanography 46, no. 6 (June 2016): 1705–16. http://dx.doi.org/10.1175/jpo-d-15-0221.1.
Full textAbstract:
AbstractA rapid and broadband (1 h, 1 < f < 400 Hz) increase in pressure and vertical velocity on the deep ocean floor was observed on seven instruments comprising a 20-km array in the northeastern subtropical Pacific. The authors associate the jump with the passage of a cold front and focus on the 4- and 400-Hz spectra. At every station, the time of the jump is consistent with the front coming from the northwest. The apparent rate of progress, 10–20 km h−1 (2.8–5.6 m s−1), agrees with meteorological observations. The acoustic radiation below the front is modeled as arising from a moving half-plane of uncorrelated acoustic dipoles. The half-plane is preceded by a 10-km transition zone, over which the radiator strength increases linearly from zero. With this model, the time derivative of the jump at a station yields a second and independent estimate of the front’s speed, 8.5 km h−1 (2.4 m s−1). For the 4-Hz spectra, the source physics is taken to be Longuet-Higgins radiation. Its strength depends on the quantity , where Fζ is the wave amplitude power spectrum and I the overlap integral. Thus, the 1-h time constant observed in the bottom data implies a similar time constant for the growth of the wave field quantity behind the front. The spectra at 400 Hz have a similar time constant, but the jump occurs 25 min later. The implications of this difference for the source physics are uncertain.
8
Reeves, Heather Dawn, Kimberly L. Elmore, Geoffrey S. Manikin, and David J. Stensrud. "Assessment of Forecasts during Persistent Valley Cold Pools in the Bonneville Basin by the North American Mesoscale Model." Weather and Forecasting 26, no. 4 (August 1, 2011): 447–67. http://dx.doi.org/10.1175/waf-d-10-05014.1.
Full textAbstract:
Abstract North American Mesoscale Model (NAM) forecasts of low-level temperature and dewpoint during persistent valley cold pools in the Bonneville Basin of Utah are assessed. Stations near the east sidewall have a daytime cold and nighttime warm bias. This is due to a poor representation of the steep slopes on this side of the basin. Basin stations where the terrain is better represented by the model have a distinct warm, moist bias at night. Stations in snow-covered areas have a cold bias for both day and night. Biases are not dependent on forecast lead or validation time. Several potential causes for the various errors are considered in a series of sensitivity experiments. An experiment with 4-km grid spacing, which better resolves the gradient of the slopes on the east side of the basin, yields smaller errors along the east corridor of the basin. The NAM assumes all soil water freezes at a temperature of 273 K. This is likely not representative of the freezing temperature in the salt flats in the western part of the basin, since salt reduces the freezing point of water. An experiment testing this hypothesis shows that reducing the freezing point of soil water in the salt flats leads to an average error reduction between 1.5 and 4 K, depending on the station and time of day. Using a planetary boundary layer scheme that has greater mixing alleviates the cold bias over snow somewhat, but the exact source of this bias could not be determined.
9
GLOJEK, Kristina, Asta GREGORIČ, Griša MOČNIK, Andrea CUESTA-MOSQUERA, Alfred WIEDENSOHLER, Luka DRINOVEC, and Matej OGRIN. "Hidden black carbon air pollution in hilly rural areas—a case study of Dinaric depression." European Journal of Geography 11, no. 2 (December 12, 2020): 105–22. http://dx.doi.org/10.48088/ejg.k.glo.11.2.105.122.
Full textAbstract:
Air pollution is not an exclusively urban problem as wood burning is a widespread practice in rural areas. As we lack information on the air quality situation in rural mountainous regions, our aim is to examine equivalent black carbon (eBC) pollution in a typical rural karst area in the settlement of Loški Potok (Slovenia). eBC mass concentrations were measured by Aethalometer (AE-33) at two sites in Retje karst depression. The rural village station was located at the bottom of the karst depression whereas the rural background station was positioned at the top of the hill. We show the diurnal variation of equivalent black carbon mass concentrations for different seasons. In the populated karst depression, the major source of eBC pollution are households using wood as a heating fuel reaching the highest mass concentrations in winter. Diurnal pattern of eBC from biomass burning and traffic differ due to different source activity and it is influenced by typical formation of a cold air pool from late afternoon until late morning, restricting the dispersion of local emissions. The large difference in mass concentrations between the lowest part of the village (rural station) and the top of the hill (rural background station) indicates that in a vertically stratified and stable atmosphere local sources of black carbon have a major impact on air quality conditions in the area studied. Since in Alpine and Dinaric regions there are many similar inhabited areas, we can expect similar air quality conditions also in other rural hilly areas with limited self-cleaning air capacity.
10
Zi, WANG, TANG Yong, FU Yuanyuan, MENG Wei, WANG Shuai, and LIU Xiaolin. "Monitoring of biomass at Cooling Water System of hongyanhe nuclear power plant by using acoustic methods." E3S Web of Conferences 194 (2020): 01007. http://dx.doi.org/10.1051/e3sconf/202019401007.
Full textAbstract:
In recent years, there have been large-scale jellyfish outbreaks in the Bohai Sea in summer, which have greatly affected the water intake for cold source of Hongyanhe nuclear power station in Fuzhou bay and threatened the normal operation. This study aims at early warning of invasion of jellyfish, designs and develops acoustic monitoring system for cold source biological (jellyfish)by using ascientificechosounder (EY60,70kHz,Simrad), and carries out real-time monitoring of the echo of cold source biological entering water intake, so as to obtain the resource density of jellyfish from June to September 2019. The acoustic data is processed with a software of Echoview to calculate the average SV and detect the strength of the single target to calculate the daily average flux of the monitoring point. According to the monitoring results, the maximum and minimum daily average values of SV were -62.7dB and -80.0dB, respectively. The maximum and minimum daily average values of target strength are -37.2dB and -81.0dB, respectively. The maximum and minimum daily average values of flux are 5.36ind/(s•m2) and 1.2x10-5ind/(s•m2).Combined with the daily cleaning amount of the monitoring point back-end intercepting network and meteorological data, the comparative analysis is carried out to determine the index level of the acoustic warning for cold source biological flowing into the water intake according to the correlation between average flux and amount of cleaned net.
11
Yu, Yan Shun, Pu Hua Qian, and Shao Fan Zhang. "Development and Validation of Mathematical Model for Tailrace Tunnel Ventilating Process in Hydropower Station." Applied Mechanics and Materials 71-78 (July 2011): 4069–73. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.4069.
Full textAbstract:
When outdoor air flowing through the tailrace tunnel, it will be handled and its thermodynamic conditions will change under the differences of temperature and water vapor pressure between air and water surface, air and tunnel wall. Utilizing the handled air for space cooling in hydropower station is an energy saving, environmental protection and renewable application of natural cold source. In this paper, a detailed quasi-three-dimensional mathematical model of heat and moisture transfer of tailrace tunnel ventilating was developed and validated against the field test data from Yingxiuwan hydropower station, and the validation shows that the model predicts the test results very well. The model can be used to predict the heat and moisture performance of tailrace tunnel ventilating system.
12
Goodwin, I. D. "The Nature and Origin of a Jökulhlaup Near Casey Station, Antarctica." Journal of Glaciology 34, no. 116 (1988): 95–101. http://dx.doi.org/10.1017/s0022143000009114.
Full textAbstract:
Abstract A jökulhlaup event of 6 months duration occurred near Casey Station, Law Dome, Antarctica, in late March (austral autumn) 1985. This was followed by sporadic outbursts during the austral autumn and winter of 1986. The event is the first recorded outburst of water from beneath a cold ice-cap terminus on Law Dome and, to the author’s knowledge, in Antarctica. From the results of oxygen-isotope and solute analysis, the water was found to have originated as basal melt water. It contained a high total solute load with a dominant enrichment in alkalis, indicting that it had been squeezed through subglacial sediments for an extensive time period. Evidence from the subglacial topography, basal ice exposures, and the sedimentology of nearby supraglacial moraines supports the presence of an ice-marginal subglacial water reservoir as the jökulhlaup source.
13
Goodwin, I. D. "The Nature and Origin of a Jökulhlaup Near Casey Station, Antarctica." Journal of Glaciology 34, no. 116 (1988): 95–101. http://dx.doi.org/10.3189/s0022143000009114.
Full textAbstract:
AbstractA jökulhlaup event of 6 months duration occurred near Casey Station, Law Dome, Antarctica, in late March (austral autumn) 1985. This was followed by sporadic outbursts during the austral autumn and winter of 1986. The event is the first recorded outburst of water from beneath a cold ice-cap terminus on Law Dome and, to the author’s knowledge, in Antarctica. From the results of oxygen-isotope and solute analysis, the water was found to have originated as basal melt water. It contained a high total solute load with a dominant enrichment in alkalis, indicting that it had been squeezed through subglacial sediments for an extensive time period. Evidence from the subglacial topography, basal ice exposures, and the sedimentology of nearby supraglacial moraines supports the presence of an ice-marginal subglacial water reservoir as the jökulhlaup source.
14
Wang, Zhiyi, Jiachen Zhong, and Zudong Pan. "Research of cooling load & chiller selection in metro station." International Journal of Low-Carbon Technologies 15, no. 4 (April 7, 2020): 506–12. http://dx.doi.org/10.1093/ijlct/ctaa015.
Full textAbstract:
Abstract Air conditioning is of the most energy saving potential system in the metro station. This study analyzes the composition and characteristics of air conditioning cooling load in a metro station. The hourly distribution and the proportion of each cooling load are calculated. The results show that cooling load fluctuation of metro air conditioning is large, and the operating time of different load varies greatly. According to the air conditioning cooling load, the coefficient of performance of the fixed frequency screw, variable frequency screw, series countercurrent screw and magnetic bearing centrifugal chiller under the load of 20–100% are tested. The annual operating cost of four chillers is compared. Test results show that the magnetic bearing centrifugal chiller has a much higher coefficient of performance at part load and lower annual operating cost. Increased initial investment can be recovered in less than 2 years. The magnetic bearing centrifugal chiller is suitable as a cold source of air conditioning system in the metro station.
15
Gaffin, David M. "Foehn Winds That Produced Large Temperature Differences near the Southern Appalachian Mountains." Weather and Forecasting 22, no. 1 (February 1, 2007): 145–59. http://dx.doi.org/10.1175/waf970.1.
Full textAbstract:
Abstract A 30-yr (1971–2000) study was conducted to 1) determine the typical characteristics and synoptic conditions of foehn wind events that produced large temperature differences near the southern Appalachian Mountains and 2) further examine those events that produced dewpoint rises. Foehn wind events were identified on both the western and eastern sides of the southern Appalachians by comparing temperatures between a station immediately adjacent to the southern Appalachians (foehn station) and two nearby stations located farther from the mountains (nonfoehn station). A foehn wind event occurred when the following criteria were met: the daily maximum or minimum temperature at the foehn station was at least 3°C (∼5°F) higher than the nonfoehn station, winds of at least 2.5 m s−1 (∼5 kt) at the foehn station must have been from a downslope direction, and warming of at least 3°C (∼5°F) must have occurred during the period of downslope winds. Foehn wind events on the western side typically occurred as southeasterly winds developed ahead of a low pressure system over the mid–Mississippi River valley, while foehn wind events on the eastern side were typically the result of northwesterly winds behind the passage of a shallow cold front. The relatively warm 850-hPa air mass, which was only a couple of degrees cooler than the surface temperatures, was likely the source region of the foehn winds on both sides, although additional flow through gaps likely contributed to the less than theoretically possible warming observed at the foehn stations. Composite soundings of the foehn wind events revealed a vertical temperature and wind profile that was conducive to large-amplitude mountain wave formation, especially on the western side of the southern Appalachians. An interesting (and possibly unique) finding observed with these southern Appalachian foehn wind events (compared with other documented foehn wind events) was the rise in surface dewpoints at the foehn stations during nearly three-fourths of the events on the western side and around one-third of the events on the eastern side. A comparison of the dewpoint-rise composites to the composites from all foehn wind events near the southern Appalachians revealed that the rise in surface dewpoints was mainly the result of a drier initial surface air mass (compared with the 850-hPa air mass) and not necessarily a more moist 850-hPa air mass.
16
Sala, Gabriele, Jiao Y. Y. Lin, Van B. Graves, and Georg Ehlers. "Conceptual design of CHESS, a new direct-geometry inelastic neutron spectrometer dedicated to studying small samples." Journal of Applied Crystallography 51, no. 2 (March 12, 2018): 282–93. http://dx.doi.org/10.1107/s1600576718002224.
Full textAbstract:
CHESS is a new direct-geometry inelastic spectrometer, which is planned for the Second Target Station (STS) at the Spallation Neutron Source (SNS) in Oak Ridge. It will take full advantage of the increased peak brilliance of the high-brightness STS coupled moderators and of recent advances in instrument design and technology to achieve unprecedented performance for inelastic scattering in the cold energy range. This paper presents a conceptual design that addresses key requirements and technical solutions which are derived directly from the science case and anticipated use of the instrument.
17
Bageston, J. V., C. M. Wrasse, D. Gobbi, H. Takahashi, and P. B. Souza. "Observation of mesospheric gravity waves at Comandante Ferraz Antarctica Station (62° S)." Annales Geophysicae 27, no. 6 (June 26, 2009): 2593–98. http://dx.doi.org/10.5194/angeo-27-2593-2009.
Full textAbstract:
Abstract. An airglow all-sky imager was operated at Comandante Ferraz Antarctica Station (62.1° S, 58.4° W), between April and October of 2007. Mesospheric gravity waves were observed using the OH airglow layer during 43 nights with good weather conditions. The waves presented horizontal wavelengths between 10 and 60 km and observed periods mainly distributed between 5 and 20 min. The observed phase speeds range between 5 m/s and 115 m/s; the majority of the wave velocities were between 10 and 60 m/s. The waves showed a preferential propagation direction towards the southwest in winter (May to July), while during spring (August to October) there was an anisotropy with a preferential propagation direction towards the northwest. Unusual mesospheric fronts were also observed. The most probable wave source could be associated to orographic forcing, cold fronts or strong cyclonic activity in the Antarctica Peninsula.
18
Bonne, Jean-Louis, Hanno Meyer, Melanie Behrens, Julia Boike, Sepp Kipfstuhl, Benjamin Rabe, Toni Schmidt, Lutz Schönicke, Hans Christian Steen-Larsen, and Martin Werner. "Moisture origin as a driver of temporal variabilities of the water vapour isotopic composition in the Lena River Delta, Siberia." Atmospheric Chemistry and Physics 20, no. 17 (September 9, 2020): 10493–511. http://dx.doi.org/10.5194/acp-20-10493-2020.
Full textAbstract:
Abstract. In the context of the Arctic amplification of climate change affecting the regional atmospheric hydrological cycle, it is crucial to characterize the present-day moisture sources of the Arctic. The isotopic composition is an important tool to enhance our understanding of the drivers of the hydrological cycle due to the different molecular characteristics of water stable isotopes during phase change. This study introduces 2 years of continuous in situ water vapour and precipitation isotopic observations conducted since July 2015 in the eastern Siberian Lena delta at the research station on Samoylov Island. The vapour isotopic signals are dominated by variations at seasonal and synoptic timescales. Diurnal variations of the vapour isotopic signals are masked by synoptic variations, indicating low variations of the amplitude of local sources at the diurnal scale in winter, summer and autumn. Low-amplitude diurnal variations in spring may indicate exchange of moisture between the atmosphere and the snow-covered surface. Moisture source diagnostics based on semi-Lagrangian backward trajectories reveal that different air mass origins have contrasting contributions to the moisture budget of the Lena delta region. At the seasonal scale, the distance from the net moisture sources to the arrival site strongly varies. During the coldest months, no contribution from local secondary evaporation is observed. Variations of the vapour isotopic composition during the cold season on the synoptic timescale are strongly related to moisture source regions and variations in atmospheric transport: warm and isotopically enriched moist air is linked to fast transport from the Atlantic sector, while dry and cold air with isotopically depleted moisture is generally associated with air masses moving slowly over northern Eurasia.
19
Liu, Jianwei, Zheyong Wang, Peng Shan, Jinyu Wang, and Cuiping Wang. "Investigation and low energy improvement of the thermal environment of work areas in the Qingdao Metro in winter." Building Services Engineering Research and Technology 41, no. 1 (August 3, 2019): 60–72. http://dx.doi.org/10.1177/0143624419867198.
Full textAbstract:
Few studies have investigated the thermal environment of the work area hall in underground metro stations during winter. Two underground stations were chosen within Qingdao Metro Lines 2 and 3 to investigate the thermal environment in the work area hall in northern city metros in China. Air temperatures and wind velocity parameters were identified as key influencing factors and were continuously measured in the work area. The study found that the thermal environment fluctuates frequently in the work area throughout the day. Changes in temperatures and wind speeds were periodically caused by piston wind flowing from the platform level. To improve this heating situation in the work area in winter, the study proposes recycling waste heat from the power equipment rooms, using the air source but through the water cycle heat pump system. Insights from the study may help save energy and improve the thermal environment, and could be applied across metro stations in north China cities in winter. Practical application: The thermal comfort of the working area in the metro station hall is extremely poor as indicated by a study of Qingdao Metro stations. This paper explores the application of a heat pump as a means of heating the working area to improve the cold and damp winter environment for the metro staff using waste heat from the machine rooms.
20
Luz, A. P., E. M. P. Ciapina, R. C. Gamba, M. S. Lauretto, E. W. C. Farias, M. C. Bicego, S. Taniguchi, R. C. Montone, and V. H. Pellizari. "Potential for bioremediation of hydrocarbon polluted soils in the Maritime Antarctic." Antarctic Science 18, no. 3 (August 24, 2006): 335–43. http://dx.doi.org/10.1017/s0954102006000381.
Full textAbstract:
Human activity in the Antarctic requires the use of petroleum hydrocarbons as the main energy source for a variety of operations. In the current study, in situ soil microcosms were constructed in the proximity of the Brazilian Antarctic Station Comandante Ferraz, King George Island, South Shetland Islands, to analyse the effect of oil amendment on the indigenous bacterial community in contaminated and uncontaminated sites to assess the potential for bioremediation. Microcosms were sampled for heterotrophic and hydrocarbon-degrader bacterial counts, pH, temperature, moisture, nutrient levels and petroleum hydrocarbons. Total organic carbon, nitrogen and phosphorus contents were generally low in the Antarctic cryosols. According to statistical analysis based on Colony Forming Unit numbers, significant bacterial populations were present in all microcosms, with larger numbers observed in oil amended than in non-amended soils. Aliphatic and aromatic fractions of diesel fuel were detected in the soil microcosms, and significant quantities were removed during the experiment. These results strongly suggest that the cold-adapted bacterial community present in soils around the Brazilian Antarctic station has the potential to adapt and utilize the oil as a carbon source. This knowledge can contribute both to bioremediation technology and the goals of the the Antarctic Treaty which prohibits the introduction of foreign organisms into the region.
21
Wong, W. "LNG Power Recovery." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 208, no. 1 (February 1994): 3–12. http://dx.doi.org/10.1243/pime_proc_1994_208_003_02.
Full textAbstract:
The thermal efficiency of a Carnot cycle is limited by the maximum and minimum temperatures available. The construction of LNG (liquid natural gas) terminals and the need to vaporize LNG offers a cooling source at a very much lower temperature than sea water. By using the cold sink and by adapting the waste heat available from a combined cycle plant, it is possible to recover power from the vaporization of LNG. This is done by the use of a reverse cascade refrigeration process where energy is extracted by expanders instead of energy input by compressors. The paper explains how the hot and cold processes can be integrated to produce a compound cycle with an overall efficiency of some 55 per cent or more depending on the quantity of LNG to be vaporized. Special reference is given to the features needed for the rotating equipment and how equipment selection is critical to the realization of a practical working power station.
22
Landais, A., A. Ekaykin, E. Barkan, R. Winkler, and B. Luz. "Seasonal variations of 17 O-excess and d-excess in snow precipitation at Vostok station, East Antarctica." Journal of Glaciology 58, no. 210 (2012): 725–33. http://dx.doi.org/10.3189/2012jog11j237.
Full textAbstract:
AbstractThe use of water isotopes in polar regions is essential for reconstructing past climate over glacial-interglacial cycles. In addition to δD or δ18O, linearly related to condensation temperature, the second-order parameters, d-excess and 17O-excess, provide important information on the climatic conditions of the source of precipitations. In order to best interpret the glacial-interglacial records of d-excess and 17O-excess in polar ice cores, it is important to document their present variability, especially in remote and cold regions of East Antarctica. Indeed, the current climatic conditions encountered in these regions provide a good analogy with glacial climatic conditions in a large part of Antarctica. Here we present the first seasonal variations of 17O-excess and d-excess at Vostok station on an event basis (i.e. samples were collected immediately after each precipitation event) over 1 year. These records show strong correlation between 17O-excess and δ18O over the course of the year, with an amplitude 40 per meg (10-3%) in the 17O-excess seasonal cycle, and strong anticorrelation between d-excess and δ18O, with d-excess variations up to 20%. The d-excess and 17O-excess variations can be explained by the influence of kinetic fractionation at very low temperatures. The comparison with simple isotopic models confirms this explanation, but cannot explain the link between 17O-excess, d-excess and temperature without (1) a particular relationship between condensation and surface temperature and/or (2) seasonal changes in the climatic conditions of the source regions
23
Farah, Antoine, Paolo Villani, Clemence Rose, Sebastien Conil, Laurent Langrene, Paolo Laj, and Karine Sellegri. "Characterization of Aerosol Physical and Optical Properties at the Observatoire Pérenne de l’Environnement (OPE) Site." Atmosphere 11, no. 2 (February 7, 2020): 172. http://dx.doi.org/10.3390/atmos11020172.
Full textAbstract:
The Observatoire Pérenne de l’Environnement (OPE) station is a rural background site located in North-Eastern France. Besides emissions from agricultural activities, the site is located far from local emissions but at an even distance from the intense emission zones of Western Germany to the north-east and the Paris area to the south-west. In the paper, we report and analyze almost six years of measurements (1 May 2012 to 31 December 2018) of the optical and physical properties of aerosol particles. Based on aerosol optical and physical measurements combined with air mass back-trajectories, we investigate the dependence of these properties on air mass type. Two distinct equivalent black carbon (EBC) sources—origins-fossil fuel (FF) and biomass burning (BB)— were identified. FF was the dominant source of EBC (>70%) but showed a very marked seasonal variation. BB fraction is found higher during the cold seasons in the order of 35% (0.1 µg m−3) against 17% (0.05 µg m−3) during the warm seasons. The highest EBC and N0.54–1.15 (particles whose diameter ranged from 0.54 to 1.15 µm) median concentrations were observed during the night time and during the cold seasons compared to the warmer seasons, indicating primary sources trapped within a thin boundary layer (BL). A different behavior is found for N10–550 (particles whose diameter ranged from 10 to 550 nm) and coarse mode particles (N1.15–4.5, i.e., particles whose diameter ranged from 1.15 to 4.5 µm) median concentrations, which were observed during the warm seasons compared to the cold seasons, indicating rather biogenic secondary sources for the smaller particles, and potentially primary biogenic sources for the coarse mode particles. The scattering and absorption coefficients and single scattering albedo (SSA) show the same seasonal variations like the ones of N0.54–1.15 concentrations, indicating that particles larger than 500 nm seemed to contribute the most to the optical properties of the aerosol.
24
Pernov, Jakob Boyd, Bjarne Jensen, Andreas Massling, Daniel Charles Thomas, and Henrik Skov. "Dynamics of gaseous oxidized mercury at Villum Research Station during the High Arctic summer." Atmospheric Chemistry and Physics 21, no. 17 (September 8, 2021): 13287–309. http://dx.doi.org/10.5194/acp-21-13287-2021.
Full textAbstract:
Abstract. While much research has been devoted to the subject of gaseous elemental mercury (GEM) and gaseous oxidized mercury (GOM) in the Arctic spring during atmospheric mercury depletion events, few studies have examined the behavior of GOM in the High Arctic summer. GOM, once deposited and incorporated into the ecosystem, can pose a threat to human and wildlife health, though there remain large uncertainties regarding the transformation, deposition, and assimilation of mercury into the food web. Therefore, to further our understanding of the dynamics of GOM in the High Arctic during the late summer, we performed measurements of GEM and GOM, along with meteorological parameters and atmospheric constituents, and utilized modeled air mass history during two summer campaigns in 2019 and 2020 at Villum Research Station (Villum) in northeastern Greenland. Seven events of enhanced GOM concentrations were identified and investigated in greater detail. In general, the common factors associated with event periods at ground level were higher levels of radiation and lower H2O mixing ratios, accumulated precipitation, and relative humidity (RH), although none were connected with cold temperatures. Non-event periods at ground level each displayed a different pattern in one or more parameters when compared to event periods. Generally, air masses during event periods for both campaigns were colder and drier, arrived from higher altitudes, and spent more time above the mixed layer and less time in a cloud compared to non-events, although some events deviated from this general pattern. Non-event air masses displayed a different pattern in one or more parameters when compared to event periods, although they were generally warmer and wetter and arrived from lower altitudes with little radiation. Coarse-mode aerosols were hypothesized to provide the heterogenous surface for halogen propagation during some of the events, while for others the source is unknown. While these general patterns were observed for event and non-event periods, analysis of individual events showed more specific origins. Five of the seven events were associated with air masses that experienced similar conditions: transported from the cold, dry, and sunlit free troposphere. However, two events experienced contrasting conditions, with air masses being warm and wet with surface layer contact under little radiation. Two episodes of extremely high levels of NCoarse and BC, which appear to originate from flaring emissions in Russia, did not contribute to enhanced GOM levels. This work aims to provide a better understanding of the dynamics of GOM during the High Arctic summer.
25
Stamps, Robert H. "Comparison of Three Sprinkler Designs for Cold Protection in Shadehouses." HortScience 32, no. 3 (June 1997): 534A—534. http://dx.doi.org/10.21273/hortsci.32.3.534a.
Full textAbstract:
Water is an economical source of heat to prevent cold damage to certain crops; however, ways to reduce the quantity of this limited resource required for cold protection need to be developed. Rapidly rotating (6 rpm) wedge-drive impact sprinklers (conventional practice) were compared with a rotary action spray head and patented slow-rotating stream sprinklers for cold-protecting a subtropical crop {leatherleaf fern [Rumohra adiantiformis (Forst.) Ching]} growing in shadehouses. Treatments were applied in a 3 × 3 latin square design to nine 29 × 29-m post- and-cable shadehouses covered with woven polypropylene shade fabric designed to provide 73% shade. Temperatures in each shadehouse were monitored 45 cm above the soil surface using four constantan–copper thermocouples. Ambient temperatures and wind speeds were monitored using additional thermocouples and an anemometer at a nearby weather station. All sprinklers had 2.8-mm orifices, were operated at 0.25 Pa, and applied 0.5 (rotating stream, rotary) or 0.54 (wedge-drive) cm·hr–1 of water. During an advective freeze with windspeeds up to 19 m·s–1 and temperatures to –2°C, there were no temperature differences due to treatments. During a radiational freeze with readings below –2°C for over 12 hr and a low of –5°C, all three irrigation systems maintained thermocouples at about –1°C. No significant damage to mature fronds were detected. Percentage of immature fronds damaged was not affected by treatments and ranged from 11% for rotary to 43% for the wedge-drive sprinkler treatments. The two newer sprinkler designs (rotary action spray head and patented slow-rotating stream) provided satisfactory protection equivalent to the industry standard (wedge-drive) while using about 10% less water.
26
Engler, C., W. Birmili, G. Spindler, and A. Wiedensohler. "Analysis of exceedances in the daily PM<sub>10</sub> mass concentration (50 μg m<sup>−3</sup>) at a roadside station in Leipzig, Germany." Atmospheric Chemistry and Physics 12, no. 21 (November 5, 2012): 10107–23. http://dx.doi.org/10.5194/acp-12-10107-2012.
Full textAbstract:
Abstract. Five years of PM10 and PM2.5 ambient air measurements at a roadside, an urban, and a regional background site in Leipzig (Germany) were analyzed for violations of the legal PM10 limit value (EC, 1999). The annual mean PM10 concentrations at the three sites were well below the legal threshold of 40 μg m−3 (32.6, 22.0 and 21.7 μg m−3, respectively). At roadside, the daily maximum value of 50 μg m−3 was exceeded on 232 days (13% of all days) in 2005–2009, which led to a violation of the EC directive in three out of five years. We analysed the meteorological factors and local source contributions that eventually led to the exceedances of the daily limit value. As noted in other urban environments before, most exceedance days were observed in the cold season. Exceedance days were most probable under synoptic situations characterised by stagnant winds, low temperatures and strong temperature inversions in winter time. However, these extreme situations accounted for only less than half of the exeedance days. We also noticed a significant number of exceedance days that occurred in the cold season under south-westerly winds, and in the warm season in the presence of easterly winds. Our analysis suggests that local as well as regional sources of PM are equally responsible for exceedances days at the roadside site. The conclusion is that a combined effort of local, national and international reduction measures appears most likely to avoid systematic exceedances of the daily limit value in the future.
27
Sokolova, D. V. "ENVIRONMENTAL AND GEOGRAPHIC STUDY OF BETANIN ACCUMULATION IN PROMISING RED BEET ACCESSIONS FROM THE VIR COLLECTION." Proceedings on applied botany, genetics and breeding 180, no. 4 (January 8, 2020): 66–74. http://dx.doi.org/10.30901/2227-8834-2019-4-66-74.
Full textAbstract:
Background. Table beet (Beta vulgaris L.) is a source of ‘betanin’, a natural food dye known as food additive E-162. The VIR collection holds a large diversity of red beet accessions. It is the base for obtaining source material to breed cultivars with high betanin content.Materials and methods. In the framework of this study, which lasted from 2015 to 2018, a group of 29 accessions identified during the screening was analyzed. The pigment was assessed at the laboratory of the ECO RESOURCE Joint-Stock Company using Spectrophotometer SF-2000. Field experiments were performed according to VIR’s guidelines in 2015–2017 at Pushkin and Pavlovsk Laboratories of VIR, Volgograd Experiment Station of VIR, and Maikop Experiment Station of VIR.Results. Environmental and geographic tests demonstrated that the ability to accumulate the pigment was variable among the red beet accessions, and its concentrations were notably different. The research showed that accumulation of betanin is primarily associated with agroclimatic growing conditions. The dynamics of pigment accumulation can be both positive and negative. The optimal zone for growing the studied accession is Leningrad Province, where the highest content of betanin was observed. Mid-ripening and cold-resistant old landraces were a reference point in the search for the desired genotypes.Conclusion. The process of pigment accumulation is extremely responsive to weather conditions, soil water balance, and watering uniformity. The negative impact of these factors would smooth down the crop’s varietal polymorphism. Diseases and insect pests have led to slowing and stopping the accumulation of betanin. As a result of the comprehensive agroecological study of prototypes, promising accessions were identified and recommended for cultivation in Leningrad Province with the aim of betanin production.
28
Nie, Tangzhe, Zhongxue Zhang, Zhijuan Qi, Peng Chen, Zhongyi Sun, and Xingchao Liu. "Characterizing Spatiotemporal Dynamics of CH4 Fluxes from Rice Paddies of Cold Region in Heilongjiang Province under Climate Change." International Journal of Environmental Research and Public Health 16, no. 5 (February 26, 2019): 692. http://dx.doi.org/10.3390/ijerph16050692.
Full textAbstract:
Paddy fields have become a major global anthropogenic CH4 emission source, and climate change affects CH4 emissions from paddy ecosystems by changing crop growth and the soil environment. It has been recognized that Heilongjiang Province has become an important source of CH4 emission due to its dramatically increased rice planting area, while less attention has been paid to characterize the effects of climate change on the spatiotemporal dynamics of CH4 fluxes. In this study, we used the calibrated and validated Long Ashton Research Station Weather Generator (LARS-WG) model and DeNitrification-DeComposition (DNDC) model to simulate historical and future CH4 fluxes under RCP 4.5 and RCP 8.5 of four global climate models (GCMs) in Heilongjiang Province. During 1960–2015, the average CH4 fluxes and climatic tendencies were 145.56 kg C/ha and 11.88 kg C/ha/(10a), respectively. Spatially, the CH4 fluxes showed a decreasing trend from west to east, and the climatic tendencies in the northern and western parts were higher. During 2021–2080, the annual average CH4 fluxes under RCP 4.5 and RCP 8.5 were predicted to be 213.46 kg C/ha and 252.19 kg C/ha, respectively, and their spatial distributions were similar to the historical distribution. The average climatic tendencies were 13.40 kg C/ha/(10a) and 29.86 kg C/ha/(10a), respectively, which decreased from west to east. The simulation scenario analysis showed that atmospheric CO2 concentration and temperature affected CH4 fluxes by changing soil organic carbon (SOC) content and plant biomass. This study indicated that a paddy ecosystem in a cold region is an important part of China’s greenhouse gas emission inventory in future scenarios.
29
Laptikhovsky, Vladimir. "Oceanographic factors influencing the distribution of South American fur seal, Arctocephalus australis around the Falkland Islands before the breeding season." Journal of the Marine Biological Association of the United Kingdom 89, no. 8 (June 23, 2009): 1597–600. http://dx.doi.org/10.1017/s0025315409000770.
Full textAbstract:
Distribution of fur seals Arctocephalus australis has been studied in October 2007 on the western, southern and eastern Falkland shelves during the survey of spawning grounds of the red cod, Salilota australis. Fur seals presence/absence, numbers and sex were recorded at every oceanographic station. Animals were found foraging on the shelf edge south-west of the islands, in a productive zone with quasi-stationary eddies at a periphery of upwelling. It was also the zone of maximum abundance of lobster-krill, Munida spp.—an important food source of fur seals and aggregations of both red cod and blue whiting, Micromesistius australis. No fur seals were found in waters of the relative cold and saline Falkland Current as well as in the relatively warm, fresh and oxygen-rich waters of Argentine Drift. It allows supposing that position and extension of the foraging grounds are caused by oceanographic features determining distribution of prey species.
30
Qu, Ouyang, Yuan, and Zeng. "Steady-State Power Flow Analysis of Cold-Thermal-Electric Integrated Energy System Based on Unified Power Flow Model." Energies 12, no. 23 (November 22, 2019): 4455. http://dx.doi.org/10.3390/en12234455.
Full textAbstract:
The integrated energy system includes various energy forms, complex operation modes and tight coupling links, which bring challenges to its steady-state modeling and steady-state power flow calculation. In order to study the steady-state characteristics of the integrated energy system, the topological structure of the cold-thermal-electric integrated energy system is given firstly. Then, the steady-state model of the power subsystem, the thermal subsystem, the cold subsystem and the distributed energy station are established, the unified power flow model is established, and the Newton Raphson algorithm is used to solve the unified power flow model. Finally, the influence of the key technical parameters on the steady-state power flow of the integrated energy system is analyzed. Research results show that the photovoltaic power generation plays a supporting role in the voltage of each bus; with the increase of electric load power, the unit value of bus voltage decreases continuously; the water supply temperature of the source node has a greater impact on the steady-state flow in the pipeline and the water supply temperature of each node; the pipeline length of the heat network has a greater impact on the end temperature of the pipeline, the water supply temperature, and the return water temperature of each node. The analysis results can support the planning, design, and optimal operation of the integrated energy system.
31
Ovadnevaite, J., A. Manders, G. de Leeuw, D. Ceburnis, C. Monahan, A. I. Partanen, H. Korhonen, and C. D. O'Dowd. "A sea spray aerosol flux parameterization encapsulating wave state." Atmospheric Chemistry and Physics 14, no. 4 (February 17, 2014): 1837–52. http://dx.doi.org/10.5194/acp-14-1837-2014.
Full textAbstract:
Abstract. A new sea spray source function (SSSF), termed Oceanflux Sea Spray Aerosol or OSSA, was derived based on in-situ sea spray aerosol measurements along with meteorological/physical parameters. Submicron sea spray aerosol fluxes derived from particle number concentration measurements at the Mace Head coastal station, on the west coast of Ireland, were used together with open-ocean eddy correlation flux measurements from the Eastern Atlantic Sea Spray, Gas Flux, and Whitecap (SEASAW) project cruise. In the overlapping size range, the data for Mace Head and SEASAW were found to be in a good agreement, which allowed deriving the new SSSF from the combined dataset spanning the dry diameter range from 15 nm to 6 μm. The OSSA source function has been parameterized in terms of five lognormal modes and the Reynolds number instead of the more commonly used wind speed, thereby encapsulating important influences of wave height, wind history, friction velocity, and viscosity. This formulation accounts for the different flux relationships associated with rising and waning wind speeds since these are included in the Reynolds number. Furthermore, the Reynolds number incorporates the kinematic viscosity of water, thus the SSSF inherently includes dependences on sea surface temperature and salinity. The temperature dependence of the resulting SSSF is similar to that of other in-situ derived source functions and results in lower production fluxes for cold waters and enhanced fluxes from warm waters as compared with SSSF formulations that do not include temperature effects.
32
Cormack, Walter P. Mac, and Elda R. Fraile. "Characterization of a hydrocarbon degrading psychrotrophic Antarctic bacterium." Antarctic Science 9, no. 2 (June 1997): 150–55. http://dx.doi.org/10.1017/s0954102097000199.
Full textAbstract:
Antarctic soil chronically exposed to gas-oil was analysed in order to isolate and study the growth conditions of hydrocarbon degrading bacteria. Soil samples taken near the shoreline in Jubany Station (King George Island, South Shetland Islands) were used as inoculum in liquid culture media with crude oil as sole carbon source. A psychrotrophic Acinetobacter strain was isolated and selected for further investigations. Effects were studied of temperature, initial pH, NaCl concentration and different chemical structure of the hydrocarbon on growth. Degradation rate was determined with n-dodecane and n-hexadecane. Growth of Acinetobacter ADH-1 showed no differences at an initial pH of 7.0, 7.5 and 8.0. Optimum temperature ranged between 25–30°C but the strain was capable of growing on n-dodecane at 4°C. Growth was observed in the presence of 3.5% NaCl. A decrease in the surface tension values was observed in the culture broth during the first 20 h of incubation (from 68 din cm−1 to 31 din cm−1). This proved to be related to the cellular fraction of the culture. The study shows that Acinetobacter ADH-1 is a psychrotrophic bacteria able to grow with hydrocarbons as sole carbon and energy source and could be potentially useful to design bioremediation processes in temperate and cold climate areas.
33
Ding, Minghu, Biao Tian, Michael C. B. Ashley, Davide Putero, Zhenxi Zhu, Lifan Wang, Shihai Yang, Chuanjin Li, and Cunde Xiao. "Year-round record of near-surface ozone and O<sub>3</sub> enhancement events (OEEs) at Dome A, East Antarctica." Earth System Science Data 12, no. 4 (December 18, 2020): 3529–44. http://dx.doi.org/10.5194/essd-12-3529-2020.
Full textAbstract:
Abstract. Dome A, the summit of the East Antarctic Ice Sheet, is an area challenging to access and is one of the harshest environments on Earth. Up until recently, long-term automated observations from Dome A (DA) were only possible with very low power instruments such as a basic meteorological station. To evaluate the characteristics of near-surface O3, continuous observations were carried out in 2016. Together with observations at the Amundsen–Scott Station (South Pole – SP) and Zhongshan Station (ZS, on the southeast coast of Prydz Bay), the seasonal and diurnal O3 variabilities were investigated. The results showed different patterns between coastal and inland Antarctic areas that were characterized by high concentrations in cold seasons and at night. The annual mean values at the three stations (DA, SP and ZS) were 29.2±7.5, 29.9±5.0 and 24.1±5.8 ppb, respectively. We investigated the effect of specific atmospheric processes on near-surface summer O3 variability, when O3 enhancement events (OEEs) are systematically observed at DA (average monthly frequency peaking at up to 64.5 % in December). As deduced by a statistical selection methodology, these O3 enhancement events (OEEs) are affected by significant interannual variability, both in their average O3 values and in their frequency. To explain part of this variability, we analyzed the OEEs as a function of specific atmospheric processes: (i) the role of synoptic-scale air mass transport over the Antarctic Plateau was explored using the Lagrangian back-trajectory analysis Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) method, and (ii) the occurrence of “deep” stratospheric intrusion events was investigated using the Lagrangian tool STEFLUX. The specific atmospheric processes, including synoptic-scale air mass transport, were analyzed by the HYSPLIT back-trajectory analysis and the potential source contribution function (PSCF) model. Short-range transport accounted for the O3 enhancement events (OEEs) during summer at DA, rather than efficient local production, which is consistent with previous studies of inland Antarctica. Moreover, the identification of recent (i.e., 4 d old) stratospheric-intrusion events by STEFLUX suggested that deep events only had a minor influence (up to 1.1 % of the period, in August) on deep events during the variability in near-surface summer O3 at DA. The deep events during the polar night were significantly higher than those during the polar day. This work provides unique data on ozone variation at DA and expands our knowledge of such events in Antarctica. Data are available at https://doi.org/10.5281/zenodo.3923517 (Ding and Tian, 2020).
34
Ovadnevaite, J., A. Manders, G. de Leeuw, C. Monahan, D. Ceburnis, and C. D. O'Dowd. "A sea spray aerosol flux parameterization encapsulating wave state." Atmospheric Chemistry and Physics Discussions 13, no. 9 (September 3, 2013): 23139–71. http://dx.doi.org/10.5194/acpd-13-23139-2013.
Full textAbstract:
Abstract. A new sea spray source function (SSSF), termed Oceanflux Sea Spray Aerosol or OSSA, was derived based on in-situ sea spray measurements along with meteorological/physical parameters. Submicron sea spray fluxes derived from particle number concentration measurements at the Mace Head coastal station, on the west coast of Ireland, were used together with open-ocean eddy correlation flux measurements from the Eastern Atlantic (SEASAW cruise). In the overlapping size range, the data for Mace Head and SEASAW were found to be in a good agreement, which allowed deriving the new SSSF from the combined dataset spanning the dry diameter range from 15 nm to 6 μm. The sea spray production was parameterized in terms of 5 log-normal modes and the Reynolds number instead of the more commonly used wind speed, thereby encapsulating important influences of wave height and history, friction velocity and viscosity. This formulation accounts for the different flux relationships associated with rising and waning wind speeds since these are included in the Reynolds number. Furthermore, the Reynolds number incorporates the kinematic viscosity of water, thus the SSSF inherently includes a sea surface temperature dependence. The temperature dependence of the resulting SSSF is similar to that of other in-situ derived source functions and results in lower production fluxes for cold waters and enhanced fluxes from warm waters as compared with SSSF formulations that do not include temperature effects.
35
Legrand, M., C. Feniet-Saigne, and J. R. Petit. "Atmospheric Chemistry Changes Over The Last Climatic Cycle (180 000 Years) Inferred From The Vostok (Antarctica) Ice-Core Study." Annals of Glaciology 14 (1990): 344. http://dx.doi.org/10.1017/s0260305500009101.
Full textAbstract:
A 2 200 m-deep ice core from Vostok Station (East Antarctica) has been used for a comprehensive study of a series of ions (Na+ NH4 +, K+, H+, Ca2+, Mg2+, C1−, F−, NO3 − and SO4 2−) originating from impurities deposited over the whole last climatic cycle (180 000 years) as depicted from the isotopic composition of the ice. Concentration profiles confirm that both marine and terrestrial aerosol inputs were higher (up to five and 30 times the Holocene values respectively) during cold climatic conditions. Such large variations of marine and terrestrial aerosol concentrations measured in ice mainly reflect global (source strength and atmospheric transport efficiency) changes, and to a lesser extent local (deposition) changes. As opposed to these primary aerosols, secondary aerosols or gases (HNO3, HC1) exhibit more moderate variations. Finally, variations of other minor ions such as NH4 + provide information on the capacity of ammonia to neutralize the natural acidity of the past background atmosphere. Spectral analyses performed on our chemical profiles (200 samples) exhibit several specific periodicities (around 20 and 40 k year) close to the Earth's orbit tilt and precession frequencies which are discussed in terms of atmospheric response to climatic fluctuations.
36
Legrand, M., C. Feniet-Saigne, and J. R. Petit. "Atmospheric Chemistry Changes Over The Last Climatic Cycle (180 000 Years) Inferred From The Vostok (Antarctica) Ice-Core Study." Annals of Glaciology 14 (1990): 344. http://dx.doi.org/10.3189/s0260305500009101.
Full textAbstract:
A 2 200 m-deep ice core from Vostok Station (East Antarctica) has been used for a comprehensive study of a series of ions (Na+ NH4+, K+, H+, Ca2+, Mg2+, C1−, F−, NO3− and SO42−) originating from impurities deposited over the whole last climatic cycle (180 000 years) as depicted from the isotopic composition of the ice.Concentration profiles confirm that both marine and terrestrial aerosol inputs were higher (up to five and 30 times the Holocene values respectively) during cold climatic conditions. Such large variations of marine and terrestrial aerosol concentrations measured in ice mainly reflect global (source strength and atmospheric transport efficiency) changes, and to a lesser extent local (deposition) changes.As opposed to these primary aerosols, secondary aerosols or gases (HNO3, HC1) exhibit more moderate variations. Finally, variations of other minor ions such as NH4+ provide information on the capacity of ammonia to neutralize the natural acidity of the past background atmosphere.Spectral analyses performed on our chemical profiles (200 samples) exhibit several specific periodicities (around 20 and 40 k year) close to the Earth's orbit tilt and precession frequencies which are discussed in terms of atmospheric response to climatic fluctuations.
37
Yin, Xiufeng, Shichang Kang, Benjamin de Foy, Yaoming Ma, Yindong Tong, Wei Zhang, Xuejun Wang, Guoshuai Zhang, and Qianggong Zhang. "Multi-year monitoring of atmospheric total gaseous mercury at a remote high-altitude site (Nam Co, 4730 m a.s.l.) in the inland Tibetan Plateau region." Atmospheric Chemistry and Physics 18, no. 14 (July 24, 2018): 10557–74. http://dx.doi.org/10.5194/acp-18-10557-2018.
Full textAbstract:
Abstract. Total gaseous mercury (TGM) concentrations were continuously measured at Nam Co Station, a remote high-altitude site (4730 m a.s.l.), on the inland Tibetan Plateau, China, from January 2012 to October 2014 using a Tekran 2537B instrument. The mean concentration of TGM during the entire monitoring period was 1.33±0.24 ng m−3 (mean ± standard deviation), ranking it as the lowest value among all continuous TGM measurements reported in China; it was also lower than most of sites in the Northern Hemisphere. This indicated the pristine atmospheric environment on the inland Tibetan Plateau. Long-term TGM at the Nam Co Station exhibited a slight decrease especially for summer seasons. The seasonal variation of TGM was characterized by higher concentrations during warm seasons and lower concentrations during cold seasons, decreasing in the following order: summer (1.50±0.20 ng m−3) > spring (1.28±0.20 ng m−3) > autumn (1.22±0.17 ng m−3) > winter (1.14±0.18 ng m−3). Diurnal variations of TGM exhibited uniform patterns in different seasons: the daily maximum was reached in the morning (around 2–4 h after sunrise), followed by a decrease until sunset and a subsequent buildup at night, especially in the summer and the spring. Regional surface reemission and vertical mixing were two major contributors to the temporal variations of TGM while long-range transported atmospheric mercury promoted elevated TGM during warm seasons. Results of multiple linear regression (MLR) revealed that humidity and temperature were the principal covariates of TGM. Potential source contribution function (PSCF) and FLEXible PARTicle dispersion model (WRF-FLEXPART) results indicated that the likely high potential source regions of TGM to Nam Co were central and eastern areas of the Indo-Gangetic Plain (IGP) during the measurement period with high biomass burning and anthropogenic emissions. The seasonality of TGM at Nam Co was in phase with the Indian monsoon index, implying the Indian summer monsoon as an important driver for the transboundary transport of air pollution onto the inland Tibetan Plateau. Our results provided an atmospheric mercury baseline on the remote inland Tibetan Plateau and serve as new constraint for the assessment of Asian mercury emission and pollution.
38
Zhou, Xudong, Jan Polcher, Tao Yang, Yukiko Hirabayashi, and Trung Nguyen-Quang. "Understanding the water cycle over the upper Tarim Basin: retrospecting the estimated discharge bias to atmospheric variables and model structure." Hydrology and Earth System Sciences 22, no. 11 (November 28, 2018): 6087–108. http://dx.doi.org/10.5194/hess-22-6087-2018.
Full textAbstract:
Abstract. The bias in atmospheric variables and that in model computation are two major causes of failures in discharge estimation. Attributing the bias in discharge estimation becomes difficult if the forcing bias cannot be evaluated and excluded in advance in places lacking qualified meteorological observations, especially in cold and mountainous areas (e.g., the upper Tarim Basin). In this study, we proposed an Organizing Carbon and Hydrology In Dynamic EcosystEms (ORCHIDEE)-Budyko framework which helps identify the bias range from the two sources (i.e., forcing and model structure) with a set of analytical approaches. The latest version of the land surface model ORCHIDEE was used to provide reliable discharge simulations based on the most improved forcing inputs. The Budyko approach was then introduced to attribute the discharge bias to two sources with prescribed assumptions. Results show that, as the forcing biases, the water inputs (rainfall, snowfall or glacier melt) are very likely underestimated for the Tarim headwater catchments (−43.2 % to 21.0 %). Meanwhile, the potential evapotranspiration is unrealistically high over the upper Yarkand and the upper Hotan River (1240.4 and 1153.7 mm yr−1, respectively). Determined by the model structure, the bias in actual evapotranspiration is possible but not the only contributor to the discharge underestimation (overestimated by up to 105.8 % for the upper Aksu River). Based on a simple scaling approach, we estimated the water consumption by human intervention ranging from 213.50×108 to 300.58×108 m3 yr−1 at the Alar gauge station, which is another bias source in the current version of ORCHIDEE. This study succeeded in retrospecting the bias from the discharge estimation to multiple bias sources of the atmospheric variables and the model structure. The framework provides a unique method for evaluating the regional water cycle and its biases with our current knowledge of observational uncertainties.
39
Ding, A. J., C. B. Fu, X. Q. Yang, J. N. Sun, L. F. Zheng, Y. N. Xie, E. Herrmann, T. Petäjä, V. M. Kerminen, and M. Kulmala. "Ozone and fine particle in the western Yangtze River Delta: an overview of 1-yr data at the SORPES station." Atmospheric Chemistry and Physics Discussions 13, no. 1 (January 28, 2013): 2835–76. http://dx.doi.org/10.5194/acpd-13-2835-2013.
Full textAbstract:
Abstract. This work presents an overview of 1-yr measurements of ozone (O3) and fine particular matter (PM2.5) and related trace gases at a recently developed regional background site, the Station for Observing Regional Processes of the Earth System (SORPES), in the western part of the Yangtze River Delta (YRD) in East China. O3 and PM2.5 showed distinguished seasonal cycles but with contrast patterns: O3 reached a maximum in warm seasons but PM2.5 in cold seasons. Correlation analysis suggests a VOC-sensitive regime for O3 chemistry and also indicates a substantial formation of secondary aerosols under conditions of high O3 in summer. Compared with the National Ambient Air Quality Standards in China, our measurements report 15 days of O3 exceedance and 148 days of PM2.5 exceedance during the 1-yr period, suggesting a severe air pollution situation in this region. Case studies for typical O3 and PM2.5 episodes demonstrated that these episodes were generally associated with an air mass transport pathway over the mid-YRD, i.e. along the Nanjing-Shanghai axis with its city clusters, and showed that synoptic weather played an important role in air pollution, especially for O3. Agricultural burning activities caused high PM2.5 and O3 pollution during harvest seasons, especially in June. A calculation of potential source contributions based on Lagrangian dispersion simulations suggests that emissions from the YRD contributed to over 70% of the O3 precursor CO, with a majority from the middle-YRD. North-YRD and the North China Plain are the main contributors to PM2.5 pollution in this region, especially for the burning episode days. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving air quality in these areas through collaborative control measures among different administrative regions.
40
Ding, A. J., C. B. Fu, X. Q. Yang, J. N. Sun, L. F. Zheng, Y. N. Xie, E. Herrmann, et al. "Ozone and fine particle in the western Yangtze River Delta: an overview of 1 yr data at the SORPES station." Atmospheric Chemistry and Physics 13, no. 11 (June 14, 2013): 5813–30. http://dx.doi.org/10.5194/acp-13-5813-2013.
Full textAbstract:
Abstract. This work presents an overview of 1 yr measurements of ozone (O3) and fine particular matter (PM2.5) and related trace gases at a recently developed regional background site, the Station for Observing Regional Processes of the Earth System (SORPES), in the western part of the Yangtze River Delta (YRD) in eastern China. Ozone and PM2.5 showed strong seasonal cycles but with contrast patterns: O3 reached a maximum in warm seasons but PM2.5 in cold seasons. Correlation analysis suggests a VOC-sensitive regime for O3 chemistry and a formation of secondary aerosols under conditions of high O3 in summer. Compared with the National Ambient Air Quality Standards in China, our measurements report 15 days of O3 exceedance and 148 days of PM2.5 exceedance during the 1 yr period, suggesting a severe air pollution situation in this region. Case studies for typical O3 and PM2.5 episodes demonstrated that these episodes were generally associated with an air mass transport pathway over the mid-YRD, i.e., along the Nanjing–Shanghai axis with its city clusters, and showed that synoptic weather played an important role in air pollution, especially for O3. Agricultural burning activities caused high PM2.5 and O3 pollution during harvest seasons, especially in June. A calculation of potential source contributions based on Lagrangian dispersion simulations suggests that emissions from the YRD contributed to over 70% of the O3 precursor CO, with a majority from the mid-YRD. North-YRD and the North China Plain are the main contributors to PM2.5 pollution in this region. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving air quality in these areas through collaborative control measures among different administrative regions.
41
O'Brien, T. A., P. Y. Chuang, L. C. Sloan, I. C. Faloona, and D. L. Rossiter. "Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds." Geoscientific Model Development 5, no. 4 (August 3, 2012): 989–1008. http://dx.doi.org/10.5194/gmd-5-989-2012.
Full textAbstract:
Abstract. To model stratocumulus clouds in the regional climate model, RegCM4.1, the University of Washington (UW) turbulence parametrization has been coupled to RegCM. We describe improvements in RegCM's coastal and near-coastal climatology, including improvements in the representation of stratiform clouds. By comparing output from a 27-yr (1982–2009) simulation of the climate of western North America to a wide variety of observational data (station data, satellite data, and aircraft in situ data), we show the following: (1) RegCM-UW is appropriate for use in general regional climate studies, and (2) the UW model distinctly improves the representation of the marine boundary layer in RegCM. These model–data comparisons also show that RegCM-UW has a slight cold bias, a (wet) precipitation bias, a systematic low bias in the vertically-integrated liquid water content near the coast, and a high bias in the fractional cloud coverage. The model represents well the diurnal, monthly, and interannual variability in low clouds. These results show RegCM-UW as a nascent mesoscale stratocumulus model that is appropriate for stratocumulus investigations at scales ranging from hourly to decadal. The source code for RegCM-UW is publicly available, under the GNU license, through the International Centre for Theoretical Physics.
42
O'Brien, T. A., P. Y. Chuang, L. C. Sloan, I. C. Faloona, and D. L. Rossiter. "Coupling a new turbulence parametrization to RegCM adds realistic stratocumulus clouds." Geoscientific Model Development Discussions 4, no. 4 (December 9, 2011): 3437–84. http://dx.doi.org/10.5194/gmdd-4-3437-2011.
Full textAbstract:
Abstract. To model stratocumulus clouds in the regional climate model, RegCM4.1, the University of Washington (UW) turbulence parametrization has been coupled to RegCM. We describe improvements in RegCM's coastal and near-coastal climatology, including improvements in the representation of stratiform clouds. By comparing output from a 27-yr (1982–2009) simulation of the climate of Western North America to a wide variety of observational data (station data, satellite data, and aircraft in situ data), we show the following: (1) RegCM-UW is appropriate for use in general regional climate studies, and (2) the UW model distinctly improves the representation of the marine boundary layer in RegCM. These model-data comparisons also show that RegCM-UW has slight cold bias, a (wet) precipitation bias, a systematic low bias in the vertically-integrated liquid water content near the coast, and a high bias in the fractional cloud coverage. The model represents well the diurnal, monthly, and interannual variability in low clouds. These results show RegCM-UW as a nascent mesoscale stratocumulus model that is appropriate for stratocumulus investigations at scales ranging from hourly to decadal. The source code for RegCM-UW is publicly available, under the GNU license, through the International Centre for Theoretical Physics.
43
Olfert, Melissa, Rebecca Hagedorn, Emily Clegg, Shannon Ackerman, and Cheryl Brown. "Choice Architecture in Appalachian High Schools: Evaluating and Improving Cafeteria Environments." Nutrients 11, no. 1 (January 11, 2019): 147. http://dx.doi.org/10.3390/nu11010147.
Full textAbstract:
School meals are a primary source of nutrition for many adolescents. Determining factors that influence the selection of various foods can provide insight on strategies to improve students’ cafeteria choices. This evaluation and observation was conducted at three Appalachian high schools to assess the cafeteria environment. The study developed and implemented an assessment tool created using principles of choice architecture and behavioral economics building on the work of the Cornell Center for Behavioral Economics in Child Nutrition Programs (BEN Center). The assessment tool scored eight components of the lunchroom—the exterior, hot serving area, cold serving area, salad bar, beverage area, payment station, dining area and grab-n-go, where a higher score equals healthier components offered. High school (HS) #1 earned 73/128 points (57%), HS #2 earned 69/128 (54%), and HS #3 earned 53/102 (52%). HS #3 did not have a grab-n-go option and the final score was out of 102. Video observation was used to collect data on lunchroom activity during mealtimes. Each school received reports that highlight the results and suggest improvements to raise their score. The scoring tool represents a novel way to assess the health of school lunches, provide insights on how to improve the healthfulness of students’ lunch choice, and improve overall nutrition status.
44
Bonaglia, Stefano, Astrid Hylén, Jayne E. Rattray, Mikhail Y. Kononets, Nils Ekeroth, Per Roos, Bo Thamdrup, Volker Brüchert, and Per O. J. Hall. "The fate of fixed nitrogen in marine sediments with low organic loading: an in situ study." Biogeosciences 14, no. 2 (January 19, 2017): 285–300. http://dx.doi.org/10.5194/bg-14-285-2017.
Full textAbstract:
Abstract. Over the last decades, the impact of human activities on the global nitrogen (N) cycle has drastically increased. Consequently, benthic N cycling has mainly been studied in anthropogenically impacted estuaries and coasts, while in oligotrophic systems its understanding is still scarce. Here we report on benthic solute fluxes and on rates of denitrification, anammox, and dissimilatory nitrate reduction to ammonium (DNRA) studied by in situ incubations with benthic chamber landers during two cruises to the Gulf of Bothnia (GOB), a cold, oligotrophic basin located in the northern part of the Baltic Sea. Rates of N burial were also inferred to investigate the fate of fixed N in these sediments. Most of the total dissolved fixed nitrogen (TDN) diffusing to the water column was composed of organic N. Average rates of dinitrogen (N2) production by denitrification and anammox (range: 53–360 µmol N m−2 day−1) were comparable to those from Arctic and subarctic sediments worldwide (range: 34–344 µmol N m−2 day−1). Anammox accounted for 18–26 % of the total N2 production. Absence of free hydrogen sulfide and low concentrations of dissolved iron in sediment pore water suggested that denitrification and DNRA were driven by organic matter oxidation rather than chemolithotrophy. DNRA was as important as denitrification at a shallow, coastal station situated in the northern Bothnian Bay. At this pristine and fully oxygenated site, ammonium regeneration through DNRA contributed more than one-third to the TDN efflux and accounted, on average, for 45 % of total nitrate reduction. At the offshore stations, the proportion of DNRA in relation to denitrification was lower (0–16 % of total nitrate reduction). Median value and range of benthic DNRA rates from the GOB were comparable to those from the southern and central eutrophic Baltic Sea and other temperate estuaries and coasts in Europe. Therefore, our results contrast with the view that DNRA is negligible in cold and well-oxygenated sediments with low organic carbon loading. However, the mechanisms behind the variability in DNRA rates between our sites were not resolved. The GOB sediments were a major source (237 kt yr−1, which corresponds to 184 % of the external N load) of fixed N to the water column through recycling mechanisms. To our knowledge, our study is the first to document the simultaneous contribution of denitrification, DNRA, anammox, and TDN recycling combined with in situ measurements.
45
Kirichek, O., C. R. Lawson, G. L. Draper, D. M. Jenkins, D. J. Haynes, and S. Lilley. "Solid methane moderators: Thermodynamics and chemistry." Journal of Neutron Research 22, no. 2-3 (October 20, 2020): 281–86. http://dx.doi.org/10.3233/jnr-190132.
Full textAbstract:
The unique properties of solid methane enable the conversion of hot, energetic neutrons into cold neutrons, with an efficiency approximately 3.5 times that of liquid hydrogen based moderators. However, practical applications of solid methane in neutron moderators turned out to be much more challenging than initially expected. Exposure of solid methane at low temperatures to neutron radiation leads to a build-up of radiolysis products in the solid methane matrix. Accumulation of defects beyond some critical number can result in a spontaneous self-accelerated recombination process, which in combination with the expansion of hydrogen built up in bulk solid methane during irradiation, was believed to be responsible for the moderator’s breakdown. Here we present results of our thermodynamic model, based on the theory of thermal explosion. Our model agrees well with the test data obtained using methane moderators developed at the IPNS neutron source, based at Argonne National Laboratory and the data acquired during commissioning of the ISIS Target Station 2 solid methane moderator. We also discuss the products of radiolysis reactions generated by exposure of the condensed methane to neutron radiation. The succession of radiolysis reactions may lead to the production of long chain hydrocarbons, which can contaminate the moderator system and significantly reduce efficiency of the heat-exchanger. The possible solutions for cleaning moderators using targeted solvents are considered. In the conclusion we give some practical recommendations, based on our simulation results and operational experience.
46
Zhao, L., J. Li, S. Xu, H. Zhou, Y. Li, S. Gu, and X. Zhao. "Seasonal variations in carbon dioxide exchange in an alpine wetland meadow on the Qinghai-Tibetan Plateau." Biogeosciences Discussions 6, no. 5 (September 11, 2009): 9005–44. http://dx.doi.org/10.5194/bgd-6-9005-2009.
Full textAbstract:
Abstract. The unique climate of the alpine wetland meadow is characterized by long cold winters and short cool summers with relatively high precipitation. These factors shorten the growing season for vegetation to approximately 150 to 165 days and prolong the dormant period to almost 7 months. Understanding how environmental variables affect the processes that regulate carbon flux in alpine wetland meadow on the Qinghai-Tibetan plateau is critical important because alpine wetland meadow plays a key role in the carbon cycle of the entire plateau. To address this issue, Gross Primary Production (GPP), Ecosystem Respiration (Reco), and Net Ecosystem CO2 Exchange (NEE) were examined for an alpine wetland meadow at the Haibei Research Station of the Chinese Academy of Sciences. The measurements covered three years and were made using the eddy covariance method. Seasonal trends of both GPP and Reco, followed closely changes in Leaf Area Index (LAI). Reco, exhibited the same exponential variation as soil temperature with seasonally-dependent R10 (the ecosystem respiration rate (μmol CO2 m−2 s−1) at the soil temperature reach 283.16 K (10°C)). Yearly average GPP, Reco, and NEE (which were 575.7, 676.8 and 101.1 gCm−2, respectively, for 2004 year, and 682.9, 726.4 and 44.0 gCm−2 for 2005 year, and 630.97, 808.2 and 173.2 gCm−2 for 2006 year) values indicated that the alpine wetland meadow was a moderately important source of CO2. The observed carbon dioxide fluxes in this alpine wetland meadow plateau are high in comparison with other alpine meadow environments such as Kobresia humilis meadow and shrubland meadow located in similar areas. And the cumulative NEE data indicated that the alpine wetland meadow is a source of atmospheric CO2 during the study years. CO2 emissions are large on elevated microclimatology areas on the meadow floor regardless of temperature. Furthermore, relatively low Reco, levels occurred during the non-growing season after a late rain event. This result is contradicted observations in alpine shrubland meadow. The timing of rain events had more impact on ecosystem GPP and NEE.
47
Malla, Bikash, Rajani Ghaju Shrestha, Sarmila Tandukar, Dinesh Bhandari, Ocean Thakali, Jeevan B. Sherchand, and Eiji Haramoto. "Detection of Pathogenic Viruses, Pathogen Indicators, and Fecal-Source Markers within Tanker Water and Their Sources in the Kathmandu Valley, Nepal." Pathogens 8, no. 2 (June 19, 2019): 81. http://dx.doi.org/10.3390/pathogens8020081.
Full textAbstract:
Tanker water is used extensively for drinking as well as domestic purposes in the Kathmandu Valley of Nepal. This study aimed to investigate water quality in terms of microbial contamination and determine sources of fecal pollution within these waters. Thirty-one samples from 17 tanker filling stations (TFSs) and 30 water tanker (WT) samples were collected during the dry and wet seasons of 2016. Escherichia coli was detected in 52% of the 31 TFS samples and even more frequently in WT samples. Of the six pathogenic viruses tested, enteroviruses, noroviruses of genogroup II (NoVs-GII), human adenoviruses (HAdVs), and group A rotaviruses were detected using quantitative PCR (qPCR) at 10, five, four, and two TFSs, respectively, whereas Aichi virus 1 and NoVs-GI were not detected at any sites. Index viruses, such as pepper mild mottle virus and tobacco mosaic virus, were detected using qPCR in 77% and 95% out of 22 samples, respectively, all of which were positive for at least one of the tested pathogenic viruses. At least one of the four human-associated markers tested (i.e., BacHum, HAdVs, and JC and BK polyomaviruses) was detected using qPCR in 39% of TFS samples. Ruminant-associated markers were detected at three stations, and pig- and chicken-associated markers were found at one station each of the suburbs. These findings indicate that water supplied by TFSs is generally of poor quality and should be improved, and proper management of WTs should be implemented.
48
Kariyapperuma, Kumudinie A., Adriana Furon, and Claudia Wagner-Riddle. "Non-growing season nitrous oxide fluxes from an agricultural soil as affected by application of liquid and composted swine manure." Canadian Journal of Soil Science 92, no. 2 (February 2012): 315–27. http://dx.doi.org/10.4141/cjss2011-059.
Full textAbstract:
Kariyapperuma, K. A., Furon, A. and Wagner-Riddle, C. 2012. Non-growing season nitrous oxide fluxes from an agricultural soil as affected by application of liquid and composted swine manure. Can. J. Soil Sci. 92: 315–327. Agricultural soils have been recognized as a significant source of anthropogenic nitrous oxide (N2O) emissions, an important greenhouse gas and contributor to stratospheric ozone destruction. Application of liquid swine manure (LSM) has been reported to increase direct N2O emissions from agricultural soils. Composting of LSM with straw under forced aeration has been suggested as a mitigation practice for emissions of N2O. In cold climates, up to 70% of total annual soil N2O emissions have been observed during winter and spring thaw. Non-growing season soil N2O emissions after field application of composted swine manure (CSM) versus LSM have not been directly compared in past studies. A 2-yr field experiment was conducted at the Arkell Research Station, Ontario, Canada, as a part of a larger study to evaluate composting as a mitigation strategy for greenhouse gases (GHGs). The objectives were to quantify and compare non-growing season N2O fluxes from agricultural soils after fall application of LSM and CSM. Nitrous oxide fluxes were measured using the flux-gradient method. Compared with LSM, CSM resulted in 57% reduction of soil N2O emissions during February to April in 2005, but emissions during the same period in 2006 were not affected by treatments. This effect was related to fall and winter weather conditions with the significant reduction occurring in the year when soil freezing was more pronounced. Compared with LSM, CSM resulted in a reduction of 37% (CO2-eq) of estimated N2O emissions per liter of treated manure and of 50% in the emission factor for the non-growing season.
49
Knowland, K. Emma, Ruth M. Doherty, Kevin I. Hodges, and Lesley E. Ott. "The influence of mid-latitude cyclones on European background surface ozone." Atmospheric Chemistry and Physics 17, no. 20 (October 19, 2017): 12421–47. http://dx.doi.org/10.5194/acp-17-12421-2017.
Full textAbstract:
Abstract. The relationship between springtime mid-latitude cyclones and background ozone (O3) is explored using a combination of observational and reanalysis data sets. First, the relationship between surface O3 observations at two rural monitoring sites on the west coast of Europe – Mace Head, Ireland, and Monte Velho, Portugal – and cyclone track frequency in the surrounding regions is examined. Second, detailed case study examination of four individual mid-latitude cyclones and the influence of the associated frontal passage on surface O3 is performed. Cyclone tracks have a greater influence on the O3 measurements at the more northern coastal European station, Mace Head, located within the main North Atlantic (NA) storm track. In particular, when cyclones track north of 53° N, there is a significant relationship with high levels of surface O3 (> 75th percentile). The further away a cyclone is from the NA storm track, the more likely it will be associated with both high and low (< 25th percentile) levels of O3 at the observation site during the cyclone's life cycle. The results of the four case studies demonstrate (a) the importance of the passage of a cyclone's cold front in relation to surface O3 measurements, (b) the ability of mid-latitude cyclones to bring down high levels of O3 from the stratosphere, and (c) that accompanying surface high-pressure systems and their associated transport pathways play an important role in the temporal variability of surface O3. The main source of high O3 to these two sites in springtime is from the stratosphere, either from direct injection into the cyclone or associated with aged airstreams from decaying downstream cyclones that can become entrained and descend toward the surface within new cyclones over the NA region.
50
Kikaj, Dafina, Janja Vaupotič, and Scott D. Chambers. "Identifying persistent temperature inversion events in a subalpine basin using radon-222." Atmospheric Measurement Techniques 12, no. 8 (August 21, 2019): 4455–77. http://dx.doi.org/10.5194/amt-12-4455-2019.
Full textAbstract:
Abstract. One year of meteorological and atmospheric radon observations in a topographically complex subalpine basin are used to identify persistent temperature inversion (PTI) events. PTI events play a key role in public health due to the accumulation of urban pollutants that they cause. Two techniques are compared: a new radon-based method (RBM), based on single-height 222Rn measurements from a single centrally located station, and an existing pseudo-vertical temperature gradient method (TGM) based on observations from eight weather stations around the subalpine basin. The RBM identified six PTI events (four in winter, two in autumn), a subset of the 17 events identified by the TGM. The RBM was more consistent in its identification of PTI events for all seasons and more selective of persistent strongly stable conditions. The comparatively poor performance of the TGM was attributed to seasonal inconsistencies in the validity of the method's key assumptions (influenced by mesoscale processes, such as local drainage flows, nocturnal jets, and intermittent turbulence influence) and a lack of snow cover in the basin for the 2016–2017 winter period. Corresponding meteorological quantities for RBM PTI events (constituting 27 % of the autumn–winter cold season) were well characterized. PTI wind speeds in the basin were consistently low over the whole diurnal cycle (typically 0.2–0.6 m s−1). Suitability of the two techniques for air quality assessment was compared using hourly PM10 observations. Peak PM10 concentrations for winter (autumn) PTI events were underestimated by 13 µg m−3 (11 µg m−3) by the TGM compared with the RBM. Only the RBM indicated that nocturnal hourly mean PM10 values in winter PTI events can exceed 100 µg m−3, the upper threshold of low-level short-term PM10 exposure according to World Health Organization guidelines. The efficacy, simplicity, and cost effectiveness of the RBM for identifying PTI events has the potential to make it a powerful tool for urban air quality management in complex terrain regions, for which it adds an additional dimension to contemporary atmospheric stability classification tools. Furthermore, the long-term consistency of the radon source function will enable the RBM to be used in the same way in future studies, enabling the relative magnitude of PTI events to be gauged, which is expected to assist with the assessment of public health risks.