Top PDF Bromide and other ions in the snow, firn air, and atmospheric boundary layer at Summit during GSHOX

Bromide and other ions in the snow, firn air, and atmospheric boundary layer at Summit during GSHOX

Bromide and other ions in the snow, firn air, and atmospheric boundary layer at Summit during GSHOX

Salawitch, R. J., Canty, T., Kurosu, T., Chance, K., Liang, Q., da Silva, A., Pawson, S., Nielsen, J. E., Rodriguez, J. M., Bhartia, P. K., Liu, X., Huey, L. G., Liao, J., Stickel, R. E., Tan- ner, D. J., Dibb, J. E., Simpson, W. R., Donohoue, D., Weinheimer, A., Flocke, F., Knapp, D., Montzka, D., Neuman, J. A., Nowak, J. B., Ryerson, T. B., Oltmans, S., Blake, D. R., At- las, E. L., Kinnison, D. E., Tilmes, S., Pan, L. L., Hendrick, F., Van Roozendael, M., Kre-

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Longpath DOAS observations of surface BrO at Summit, Greenland

Longpath DOAS observations of surface BrO at Summit, Greenland

Rapid transport from the north Atlantic was observed dur- ing at least one rapid marine transport event in 2008, showing clearly that gaseous bromine species can, at times, be trans- ported directly from the Greenland east-coast to Summit in late Spring and Summer. A trajectory study by Kahl et al. (1997) shows that this type of trajectory is rare (2–4 % of annual trajectories). It thus appears that the observed type of rapid transport event is infrequent and that these events are unlikely to contribute significantly to the bromide bud- get at Summit. It is unclear how important marine influence is during other times of the year. Transport of air with low ozone associated with bromine catalyzed arctic ozone deple- tion events has been found to influence Summit in spring (Hirdman et al., 2010). While it is likely that these transport events bring gaseous bromine or aerosol bromide to Sum- mit, we have no clear evidence that this is the main source of snow bromide observed at Summit. Our observations also show that boundary layer chemistry is significantly differ- ent during these marine transport events from times when air resides on the Greenland ice sheet for extended periods of time. Other possible factors influencing bromine chemistry at Summit are the frequent fog and blowing snow events. Our LP-DOAS was not able to measure during these events, but one can speculate that bromine recycling on the ice particle surfaces can alter the partitioning between the various inor- ganic bromine species. Further studies of bromine chemistry in the presence of ice particles would be desirable, as ice particles at Summit can serve as a model for ice clouds in the upper troposphere.
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Characteristics and source apportionment of atmospheric aerosols at the summit of Mount Tai during summertime

Characteristics and source apportionment of atmospheric aerosols at the summit of Mount Tai during summertime

enables the sampling of air masses that are more representative of regional character- istics, allows examination of transport paths from other regions in Asia, and it permits the study of exchanges between the planetary boundary layer (PBL) and the free tro- posphere (Gao et al., 2005). Due to the domination of Pacific high pressure during the summer season, this site also enabled the sampling of air down-wind from a city group

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Sources of light-absorbing aerosol in arctic snow and their seasonal variation

Sources of light-absorbing aerosol in arctic snow and their seasonal variation

largely agricultural, the PMF source contributions, dominated by crop and grass burn- ing, are readily explicable. Similarly, the Tiksi back trajectories (Fig. 6b) have a major component that extends well to the south, roughly following the Ob river valley, and penetrating deeply into the agricultural fire area. In contrast, the back trajectories for Cherskiy and Bilibino (Fig. 6c) are much more localized. There are indeed some that

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Human Capital and the Recent Fall of Earnings Inequality in Brazil

Human Capital and the Recent Fall of Earnings Inequality in Brazil

where is a set of linear restrictions that transforms the unrestricted model (1) on restricted model (2). 8 In our case, the restriction implies that the age, trend and (orthogonal) time dummies are sufficient to explain the behavior of each estimated statistic order across cells and over time. Imposing the restrictions means estimating weighted least squares regressions on the grouped data, for each quantile and education group separately. This procedure will give us consistent estimates of . Under the null that the restrictions are valid, the minimized value follows a chi-square distribution with degrees of freedom equal to the number of restrictions. In order to construct the test statistics, we only have to sum up the weighted squared residuals, that is, the estimated percentiles minus the predicted values minus the orthogonal time dummies.
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Numerical tools to estimate the flux of a gas across the air-water interface and assess the heterogeneity of its forcing functions

Numerical tools to estimate the flux of a gas across the air-water interface and assess the heterogeneity of its forcing functions

substituting the adequate parameters in the model is required. This numerical tool was based on that of Johnson (2010) but underwent several upgrades: (i) it is possible to choose between single or double layer models; (ii) new numerical schemes for the effect of wind in the water-phase transfer velocity by Mackay and Yeun (1983), Carini et al. (1996), Raymond and Cole (2001), Zhao et al. (2003) and Borges et al. (2004b) were introduced; (iii) the effect of sea sur- face agitation in the water-phase transfer velocity was added; (v) the effect of atmospheric stability in both the air-side and water-side transfer velocities was added; and (iv) the effect in the water-phase transfer velocity of turbulence due to cur- rent drag with the bottom following O’Connor and Dobbins (1958) was added. The latter may play a fundamental role in regulating the gas transfer velocity in macro and mesoti- dal estuarine and lagoonary systems. The second objective of this work was to develop a numerical method that al- lows decomposing a difference in the gas fluxes between two distinct situations into the effects of their differences in the environmental variables. This enables the identifica- tion of the variables responsible by differences in fluxes be- tween two situations. The current work is intended to set the grounds for further research. This shall consist of in- cluding more environmental processes, improving the algo- rithms of the currently included ones, submitting the tools to a wide range of environmental conditions and conjugat- ing them with numerical modelling labs such as MOHID (www.MOHID.com), ECO lab (www.dhisoftware.com) and WASP (www.epa.gov/athens/research/wasp.html).
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Description and implementation of a MiXed Layer model (MXL, v1.0) for the dynamics of the atmospheric boundary layer in the Modular Earth Submodel System (MESSy)

Description and implementation of a MiXed Layer model (MXL, v1.0) for the dynamics of the atmospheric boundary layer in the Modular Earth Submodel System (MESSy)

For the lower boundary conditions, there are two possi- bilities. On one hand, MXL/MESSy offers the possibility to use interactive emission (via the ONEMIS (Kerkweg et al., 2006b) and MEGAN (Guenther et al., 2006) submodels), dry deposition (DDEP; Kerkweg et al., 2006a) and land sur- face parametrizations (Sect. 2.7). In these submodels, land surface-ABL exchange is calculated as function of land sur- face and ABL characteristics, like stomatal resistance and air temperature. On the other hand, it is possible to pre- scribe emissions and surface heat fluxes following simpli- fied functions for the users who like to keep full control over the boundary conditions of the model (Sect. 2.5). In that way, MXL/MESSy can for instance be used to evaluate the sensitivity of the chemistry in the ABL to uncertainties in emission estimates. Further, OFFEMIS (Kerkweg et al., 2006b) allows for the extraction of emission time series from an emission database, which is read by IMPORT. Addition- ally, the organic aerosol submodel ORACLE (Tsimpidi et al., 2014), allows for the representation of the organic aerosol composition and evolution.
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Boundary layer structure and decoupling from synoptic scale flow during NAMBLEX

Boundary layer structure and decoupling from synoptic scale flow during NAMBLEX

Abstract. This paper presents an overview of the meteo- rology and planetary boundary layer structure observed dur- ing the NAMBLEX field campaign to aid interpretation of the chemical and aerosol measurements. The campaign has been separated into five periods corresponding to the prevail- ing synoptic condition. Comparisons between meteorologi- cal measurements (UHF wind profiler, Doppler sodar, sonic aneometers mounted on a tower at varying heights and a standard anemometer) and the ECMWF analysis at 10 m and 1100 m identified days when the internal boundary layer was decoupled from the synoptic flow aloft. Generally the agree- ment was remarkably good apart from during period one and on a few days during period four when the diurnal swing in wind direction implies a sea/land breeze circulation near the surface. During these periods the origin of air sampled at Mace Head would not be accurately represented by back trajectories following the winds resolved in ECMWF analy- ses. The wind profiler observations give a detailed record of boundary layer structure including an indication of its depth, average wind speed and direction. Turbulence statistics have been used to assess the height to which the developing inter- nal boundary layer, caused by the increased surface drag at the coast, reaches the sampling location under a wide range of marine conditions. Sampling conducted below 10 m will be impacted by emission sources at the shoreline in all wind directions and tidal conditions, whereas sampling above 15 m is unlikely to be affected in any of the wind directions and tidal heights sampled during the experiment.
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Estimating the atmospheric boundary layer height over sloped, forested terrain from surface spectral analysis during BEARPEX

Estimating the atmospheric boundary layer height over sloped, forested terrain from surface spectral analysis during BEARPEX

for typical surface winds at Blodgett Forest, this type of analysis does not require the high rate performance of a sonic anemometer and could, in principle, be obtained with 1–10 s averaged data. Similar attempts were made by Contini et al. (2009) over flat-terrain in a coastal site of the Salentum peninsula, in Italy with a focus on longitu- dinal winds. These authors report that, among the methods they applied, the spectral

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The Effects of Gender Segregation at the Occupation, Industry, Establishment, and Job-Cell Levels on the Male-Female Wage Gap

The Effects of Gender Segregation at the Occupation, Industry, Establishment, and Job-Cell Levels on the Male-Female Wage Gap

The main lessons learned from these theories are that, while part of the wage gap is attributable to human capital differences between the genders, the process of allocation of males and females in the labor market leads to a type of sorting in which women end up relatively more concentrated in occupations, industries, firms, and occupations within establishments (job cells) that pay lower wages. This implies that empirical analyses of the determinants of the sex pay gap should take into account not only the human capital differences between the genders but also the patterns of female segregation along these dimensions. Another implication of these theories for empirical work is that unobserved (to the analyst) characteristics of workers and firms play crucial roles as determinants of wages and the sorting process of males and females in the labor market. Lack of control for unmeasured traits of workers and firms may thus generate serious biases in the estimates of the effects of gender segregation on the wages of males and females, and therefore on the gender wage gap.
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Numerical Investigation of Flow Control by Suction and Injection on a Subsonic Airfoil

Numerical Investigation of Flow Control by Suction and Injection on a Subsonic Airfoil

energy consumptive. They mainly affect the flow by the geometry of the airfoil. In contrast, active control devices use energy such as surface suction or injection. Natural laminar flow implies delaying transition via controlling the body shape to provide long runs of favorable pressure-gradient. This has been applied since the 1930s on airfoil sections to achieve lower skin friction drag. The principal types of active laminar-flow control are surface cooling and removal of a small amount of air from the boundary layer of suction. Generally, in surface injection, a secondary flow is injected from miniature openings or slots on the surface. In surface suction, the air is sucked from them. For highly swept wings, only suction can control sweep-induces cross-flow disturbances that promote boundary layer transition from laminar to turbulent [2-4] .
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The comparison of the structure and microhardness of the tool steel C90 and HS 6-5-2 remelted with the electric arc

The comparison of the structure and microhardness of the tool steel C90 and HS 6-5-2 remelted with the electric arc

The structure of the remelting zone of the steel C90 steel be- fore conventional tempering consitute cells, dendritic cells, sur- rounded with the cementite, inside of which there is a plate mar- tensite and retained austenite, whereas the structure HS 6-5-2 steel consititute cells, dendritic cells and dendrites surrounded with the eutectic, inside of which there is a plate martensite and retained austenite. Such a structure is characterized with the similar micro- hardness (790-800 HV0,065) and intensity of the tribilogical wear.
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Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide

Controls on the movement and composition of firn air at the West Antarctic Ice Sheet Divide

of the species analyzed and the responsible institutions are given in Table 1. All sam- ples were collected through Dekoron TM tubing using a Metal Bellows MB-158 pump (Senior Aerospace, Sharon MA), with a KNF-NO5 pump with Viton valves and di- aphragm (KNF Neuberger, Trenton NJ) added in series for the UC Irvine and NOAA HATS flasks. As described by Severinghaus et al. (2010), we used a system in

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Mesoscale modeling study of the interactions between aerosols and PBL meteorology during a haze episode in China Jing-Jin-Ji and its near surrounding region – Part 2: Aerosols' radiative feedback effects

Mesoscale modeling study of the interactions between aerosols and PBL meteorology during a haze episode in China Jing-Jin-Ji and its near surrounding region – Part 2: Aerosols' radiative feedback effects

Che, H., Xia, X., Zhu, J., Li, Z., Dubovik, O., Holben, B., Goloub, P., Chen, H., Estelles, V., Cuevas-Agulló, E., Blarel, L., Wang, H., Zhao, H., Zhang, X., Wang, Y., Sun, J., Tao, R., Zhang, X., and Shi, G.: Column aerosol optical properties and aerosol radiative forcing dur- ing a serious haze-fog month over North China Plain in 2013 based on ground-based sun- photometer measurements, Atmos. Chem. Phys., 14, 2125–2138, doi:10.5194/acp-14-2125-

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Increasing ozone in marine boundary layer inflow at the west coasts of North America and Europe

Increasing ozone in marine boundary layer inflow at the west coasts of North America and Europe

for all of the data measured in each season at each site that satisfy the wind selection criteria. The differences in these averages divided by the number of years between the cen- tral time of each data set (13 or 13.5 years) gives an approx- imate trend, and error propagation techniques provide 2σ confidence limits for those trends. The results are highly sta- tistically significant for all seasons, and agree well with the trends listed in Table 5: 0.46±0.29, 0.47±0.18, 0.34±0.18, and 0.25±0.15 ppbv/yr in winter, spring, summer and au- tumn, respectively. Of course this agreement is expected, since these data are all included in the composite linear re- gression. In summary, all of the data sets examined, both by linear regression techniques and this simpler analysis, indi- cate that statistically robust increases have occurred in the O 3
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Fields of study and the earnings gap by race in Brazil

Fields of study and the earnings gap by race in Brazil

The 2000 and 2010 codes for field of study are matched following the description reported in Table A1 (columns (1) and (2)). For many areas of study, mainly for those comprising an important share of the individuals with tertiary education in Brazil, such as medicine and law, the match is clear. As can be seen, there are fields in the 2000 classification system, such as business administration and arts, which refer to many narrower codes in the 2010 system. Also, a few codes in 2000 are not assigned to a code in 2010. This is done in situations where the program in the former system does not have an equivalent one in the latter (geography, physical education), or the match is not considered clear, as are the cases of science programs, other agriculture programs, other social science, and other arts and languages programs.
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Analysis Of Lean Accounting JIT And Balance Scorecard In The Companys Lean Manufacturing

Analysis Of Lean Accounting JIT And Balance Scorecard In The Companys Lean Manufacturing

customer response times.[1]. Lean manufacturing can also purposed to lean effort and wasting time to increase goal production. By disspeared all 0f them wastes such as time, effort and finance. The company can competition with the other companies. And face uncertaintly in the future. This terms supported. Wang [2011] Lean manufacturing is the production of goods using less of everything compared to mass production: less waste, less human effort, less manufacturing space, less investment in tools, and less engineering time to develop a new product.[9] furthermore Boczko [2007] said that Lean manufacturing is a generic process management philosophy derived mostly from the Toyota Production System (TPS) as well as other industrial best practices. Lean manufacturing is renowned for its focus on reduction of Toyota’s original ―seven wastes‖ in order to improve overall customer satisfaction [9]. Lean manufacturing has good designed to the company that especially in the manufacturing field. Furthermore Hansen [2007] described that Lean manufacturing is thus an approach designed to eliminate waste and maximize customer value. It is characterized by delivering the right product, in the right quantity, with the right quality (zero-defect), at the exact time the customer needs it and at the lowest possible cost [7]. Line manufacturing can be priority by company to reach target achievement production appropriate costumer demand. Cesarony [2014] has opinion that Zero setup times, zero defects, zero inventories, zero waste, producing on demand, increasing a cell’s production rates, minimizing cost, and maximizing customer value represent ideal outcomes that a lean manufacturer seeks.[17]. In other hand lean manufacturing has
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Evaporation of intercepted rainfall from isolated evergreen oak trees: do the crowns behave as wet bulbs ?

Evaporation of intercepted rainfall from isolated evergreen oak trees: do the crowns behave as wet bulbs ?

thermometer is considered to be fully aspirated (Bindon, 1965). As far as we are aware, this is the first study specifically designed to measure the canopy surface temperature of an isolated tree during periods of precipitation. Several previous studies have been carried out to directly evaluate evaporation rates from artificially wetted leaves, shoots or trees in the course of which surface temperature was also measured. However, these studies were, in general, made under good weather conditions and, thus, with higher radiation levels. In spite of this important difference, all studies tend to confirm that, when completely wet, the surface temperature of a tree crown gets very close to the wet bulb temperature of the adjacent air. For example, Landsberg and Thom (1971) found indistinguishable differences between the temperature of wetted needles/shoots and the air wet bulb temperature, when trying to determine transfer coefficients for water vapour in the controlled environmental conditions of a wind tunnel. Later on, in a study using the hanging-tree method to directly measure evaporation rate from a single tree, Tekle- haimanot and Jarvis (1991) reported that surface temperature over the entire tree crown varied by no more than 0.5 8C after the tree was artificially wetted. This suggests that, when saturated, the canopy of an isolated tree has a homogeneous surface temperature, consistent with our assumption that the surface temperature of the entire wet tree crown can be adequately calculated as the average leaf temperature. Furthermore, it should be borne in mind that Teklehaimanot and Jarvis’s measurements were made under dry conditions when the energy input was certainly several times higher than that to be expected under rain. Probably, their observed maximum 0.5 8C temperature difference over the tree crown would not be reached if measurements were made during the occurrence of rainfall.
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Feasible domain of Walker's unsteady wall-layer model for the velocity profile in turbulent flows

Feasible domain of Walker's unsteady wall-layer model for the velocity profile in turbulent flows

The present work derives in detail all similarity solutions for the homogeneous diffusion differential partial equation presented in Walker et al. (1989). In doing so, a new treatment is introduced whereby the pressure term is included as a non-homogeneous contribution. To permit fast computations, interpolation functions were generated from initial and boundary value problems, to represent some complex special functions, including Ξ. The special function Ξ (Walker et al. 1989) and its derivatives are given exact expressions (see Mikhailov and Silva Freire 2012), based on original identities for the hypergeometric functions 1 F 1 and p F p .
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Vertical transport of pollutants by shallow cumuli from large eddy simulations

Vertical transport of pollutants by shallow cumuli from large eddy simulations

clouds manage to get into the inversion layer and bring pollutants there. However, the simulation shows very small cloud fraction (5.5 %) and low cloud top height (0.91 km on average) at 6 h. The higher tracer mixing ratio from 1.3 km to 1.6 km over cloud-free columns at 6 h compared to that over cloudy columns results from clouds that were higher and transported tracers upward at previous moments but have evaporated and

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