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Atmosphere, Volume 7, Issue 3 (March 2016) – 18 articles

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Open AccessArticle
Climate Change Vulnerabilities and Adaptation Options for Forest Vegetation Management in the Northwestern USA
Atmosphere 2016, 7(3), 46; https://doi.org/10.3390/atmos7030046 - 21 Mar 2016
Cited by 13 | Viewed by 2856
Abstract
Recent vulnerability assessments, conducted in diverse regions in the northwestern United States, indicate that many commonalities exist with respect to projected vulnerabilities to climate change. Dry forests are projected to have significant changes in distribution and abundance of species, partially in response to [...] Read more.
Recent vulnerability assessments, conducted in diverse regions in the northwestern United States, indicate that many commonalities exist with respect to projected vulnerabilities to climate change. Dry forests are projected to have significant changes in distribution and abundance of species, partially in response to higher temperature and lower soil moisture, but mostly in response to projected increases in extreme events and disturbances—drought, wildfire, and insect outbreaks. Wildfire and mountain pine beetles have caused extensive mortality across millions of hectares in this region during the past decade, and wildfire area burned is projected to increase 200%–300% by mid-21st century. Science–management partnerships associated with recent assessments have identified an extensive list of adaptation options, including both strategies (general planning) and tactics (on-the-ground projects). Most of the options focus on increasing resilience to disturbances and on reducing current stressors to resource conditions. Adaptation options are generally similar across the biogeographically diverse region covered by assessments, suggesting that there may be a limit on the number of feasible responses to climate change. Federal agencies in the northwestern United States are now using these assessments and adaptation approaches to inform sustainable resource management and planning, mostly through fine tuning of existing practices and policies. Full article
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Open AccessArticle
Comparison of Land-Use Regression Modeling with Dispersion and Chemistry Transport Modeling to Assign Air Pollution Concentrations within the Ruhr Area
Atmosphere 2016, 7(3), 48; https://doi.org/10.3390/atmos7030048 - 19 Mar 2016
Cited by 22 | Viewed by 3691
Abstract
Two commonly used models to assess air pollution concentration for investigating health effects of air pollution in epidemiological studies are Land Use Regression (LUR) models and Dispersion and Chemistry Transport Models (DCTM). Both modeling approaches have been applied in the Ruhr area, Germany, [...] Read more.
Two commonly used models to assess air pollution concentration for investigating health effects of air pollution in epidemiological studies are Land Use Regression (LUR) models and Dispersion and Chemistry Transport Models (DCTM). Both modeling approaches have been applied in the Ruhr area, Germany, a location where multiple cohort studies are being conducted. Application of these different modelling approaches leads to differences in exposure estimation and interpretation due to the specific characteristics of each model. We aimed to compare both model approaches by means of their respective aims, modeling characteristics, validation, temporal and spatial resolution, and agreement of residential exposure estimation, referring to the air pollutants PM2.5, PM10, and NO2. Residential exposure referred to air pollution exposure at residences of participants of the Heinz Nixdorf Recall Study, located in the Ruhr area. The point-specific ESCAPE (European Study of Cohorts on Air Pollution Effects)-LUR aims to temporally estimate stable long-term exposure to local, mostly traffic-related air pollution with respect to very small-scale spatial variations (≤100 m). In contrast, the EURAD (European Air Pollution Dispersion)-CTM aims to estimate a time-varying average air pollutant concentration in a small area (i.e., 1 km2), taking into account a range of major sources, e.g., traffic, industry, meteorological conditions, and transport. Overall agreement between EURAD-CTM and ESCAPE-LUR was weak to moderate on a residential basis. Restricting EURAD-CTM to sources of local traffic only, respective agreement was good. The possibility of combining the strengths of both applications will be the next step to enhance exposure assessment. Full article
(This article belongs to the Special Issue Air Quality and Source Apportionment) Printed Edition available
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Open AccessArticle
Aerosol Optical Properties over Beijing during the World Athletics Championships and Victory Day Military Parade in August and September 2015
Atmosphere 2016, 7(3), 47; https://doi.org/10.3390/atmos7030047 - 19 Mar 2016
Cited by 17 | Viewed by 2775
Abstract
A special period in Beijing from 6 August to 17 September 2015, during which the World Athletics Championships and Victory Day military parade took place, and which involved measures to restrict traffic and reduce factory emissions, was selected to analyze the aerosol optical [...] Read more.
A special period in Beijing from 6 August to 17 September 2015, during which the World Athletics Championships and Victory Day military parade took place, and which involved measures to restrict traffic and reduce factory emissions, was selected to analyze the aerosol optical properties and the impact of meteorological conditions on pollution levels. The study was based on AERONET observational and retrieval data, particulate matter measurements (TEOM 1405), meteorological data, and then the HYSPLIT model was used to analyze the pollution sources. The study period was divided into three sub-periods according to the different stages of implementation of the control measures, and the main conclusions can be summarized as follows. During the period in which the restrictive measures were applied, the air quality improved significantly, with the average value of the AOD being 0.34 ± 0.20, about 69% less than before. Meanwhile, the average Ångström exponent was about 9.5% higher than before, with an average value of 1.38 ± 0.25, indicating that the main pollutants were fine particles. Single scattering albedo decreased as wavelength increased, being higher than in the other two stages (mean value of 0.944 ± 0.045). This showed that the strong scattering capacity and absorption aerosol optical depth was at its lowest, at about 0.008 ± 0.009. The peaks of aerosol volume concentration in the fine and coarse mode were significantly reduced. Meteorological conditions also had a certain effect on the aerosol optical properties, with the blowing of clean and dry wind and the occurrence of precipitation contributing to the overall improvement in air quality. Full article
(This article belongs to the Special Issue Atmospheric Aerosols and Their Radiative Effects)
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Open AccessArticle
Soot Nanoparticles Could Partake in Nucleation of Biogenic Particles in the Atmosphere: Using Fullerene as a Model Compound
Atmosphere 2016, 7(3), 45; https://doi.org/10.3390/atmos7030045 - 14 Mar 2016
Viewed by 2386
Abstract
The detection of existence of fullerenes (C60 and C70) makes it necessary to explore whether soot nanoparticles can participate in new nanometer-sized particle formation and growth in the atmosphere. This study describes a theoretical investigation at multiple levels on the [...] Read more.
The detection of existence of fullerenes (C60 and C70) makes it necessary to explore whether soot nanoparticles can participate in new nanometer-sized particle formation and growth in the atmosphere. This study describes a theoretical investigation at multiple levels on the role of the fullerenes (as model compounds to represent nanoparticles of soot) in the formation of complexes with a common atmospheric nucleating precursor (sulfuric acid, SA) and a biogenic organic acid (cis-pinonic acid, CPA), as well as initial growth of nano-sized biogenic aerosols. Quantum chemical density-functional theory calculations identify the formation of stable fullerene-[CPA-SA] ternary complexes, which likely leads to an enhanced nucleation of SA with CPA. Relevant thermochemical parameters including the changes of Gibbs free energy, enthalpy, and entropy for the complex formation also support that fullerene-[CPA-SA] is most likely to be a newly formed nuclei. The sizes of the critical nucleus of the fullerene-[CPA-SA-H2O] systems were found to be approximately 1.3 nm by large-scale molecular dynamics simulations. This study may provide a new insight into the mechanisms underlying the formation of new particle in the atmospheric environment. Full article
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Open AccessArticle
Weather and Tourism: Thermal Comfort and Zoological Park Visitor Attendance
Atmosphere 2016, 7(3), 44; https://doi.org/10.3390/atmos7030044 - 14 Mar 2016
Cited by 17 | Viewed by 2798
Abstract
Weather events have the potential to greatly impact business operations and profitability, especially in outdoor-oriented economic sectors such as Tourism, Recreation, and Leisure (TRL). Although a substantive body of work focuses on the macroscale impacts of climate change, less is known about how [...] Read more.
Weather events have the potential to greatly impact business operations and profitability, especially in outdoor-oriented economic sectors such as Tourism, Recreation, and Leisure (TRL). Although a substantive body of work focuses on the macroscale impacts of climate change, less is known about how daily weather events influence attendance decisions, particularly relating to the physiological thermal comfort levels of each visitor. To address this imbalance, this paper focuses on ambient thermal environments and visitor behavior at the Phoenix and Atlanta zoos. Daily visitor attendances at each zoo from September 2001 to June 2011, were paired with the Physiologically Equivalent Temperature (PET) to help measure the thermal conditions most likely experienced by zoo visitors. PET was calculated using hourly atmospheric variables of temperature, humidity, wind speed, and cloud cover from 7 a.m. to 7 p.m. at each zoological park location and then classified based on thermal comfort categories established by the American Society of Heating and Air Conditioning Engineers (ASHRAE). The major findings suggested that in both Phoenix and Atlanta, optimal thermal regimes for peak attendance occurred within “slightly warm” and “warm” PET-based thermal categories. Additionally, visitors seemed to be averse to the most commonly occurring thermal extreme since visitors appeared to avoid the zoo on excessively hot days in Phoenix and excessively cold days in Atlanta. Finally, changes in the daily weather impacted visitor attendance as both zoos experienced peak attendance on days with dynamic changes in the thermal regimes and depressed attendances on days with stagnant thermal regimes. Building a better understanding of how weather events impact visitor demand can help improve our assessments of the potential impacts future climate change may have on tourism. Full article
(This article belongs to the Special Issue Tourism Climatology)
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Open AccessArticle
Reconstructing Fire Records from Ground-Based Routine Aerosol Monitoring
Atmosphere 2016, 7(3), 43; https://doi.org/10.3390/atmos7030043 - 14 Mar 2016
Cited by 2 | Viewed by 2299
Abstract
Long-term fire records are important to understanding the trend of biomass burning and its interactions with air quality and climate at regional and global scales. Traditionally, such data have been compiled from ground surveys or satellite remote sensing. To obtain aerosol information during [...] Read more.
Long-term fire records are important to understanding the trend of biomass burning and its interactions with air quality and climate at regional and global scales. Traditionally, such data have been compiled from ground surveys or satellite remote sensing. To obtain aerosol information during a fire event to use in analyzing air quality, we propose a new method of developing a long-term fire record for the contiguous United States using an unconventional data source: ground-based aerosol monitoring. Assisted by satellite fire detection, the mass concentration, size distribution, and chemical composition data of surface aerosols collected from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network are examined to identify distinct aerosol characteristics during satellite-detected fire and non-fire periods. During a fire episode, elevated aerosol concentrations and heavy smoke are usually recorded by ground monitors and satellite sensors. Based on the unique physical and chemical characteristics of fire-dominated aerosols reported in the literature, we analyzed the surface aerosol observations from the IMPROVE network during satellite-detected fire events to establish a set of indicators to identify fire events from routine aerosol monitoring data. Five fire identification criteria were chosen: (1) high concentrations of PM2.5 and PM10 (particles smaller than 2.5 and 10 in diameters, respectively); (2) a high PM2.5/PM10 ratio; (3) high organic carbon (OC/PM2.5) and elemental carbon (EC/PM2.5) ratios; (4) a high potassium (K/PM2.5) ratio; and (5) a low soil/PM2.5 ratio. Using these criteria, we are able to identify a number of fire episodes close to 15 IMPROVE monitors from 2001 to 2011. Most of these monitors are located in the Western and Central United States. In any given year within the study period fire events often occurred between April and September, especially in the two months of April and September. This ground-based fire climatology is also consistent with that derived from satellite retrievals. This study demonstrates that it is feasible to reconstruct historic records of fire events based on continuous ground aerosol monitoring. This dataset can provide not only fire activity information but also fire-induced aerosol surface concentrations and chemical composition that can be used to verify satellite-based products and evaluate air quality and climate modeling results. However, caution needs to be exercised because these indicators are based on a limited number of fire events, and the proposed methodology should be further tested and confirmed in future research. Full article
(This article belongs to the Special Issue Air Quality and Source Apportionment) Printed Edition available
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Open AccessArticle
Impacts of Soil Moisture on Typical Frontal Rainstorm in Yangtze River Basin
Atmosphere 2016, 7(3), 42; https://doi.org/10.3390/atmos7030042 - 11 Mar 2016
Cited by 2 | Viewed by 1840
Abstract
By using a coupled land surface-atmosphere model with initial conditions of varying resolution and ensembles of systematically changed soil moisture, convective-scale simulations of a typical frontal rainstorm in the Yangtze River Basin are collected to investigate: (1) effects of different datasets on the [...] Read more.
By using a coupled land surface-atmosphere model with initial conditions of varying resolution and ensembles of systematically changed soil moisture, convective-scale simulations of a typical frontal rainstorm in the Yangtze River Basin are collected to investigate: (1) effects of different datasets on the simulated frontal mesoscale convective systems (MCSs); (2) possible linkages between soil moisture, planetary boundary layer (PBL), MCSs and precipitation in this modeled rainstorm. Firstly, initial soil moisture differences can affect the PBL, MCSs and precipitation of this frontal rainstorm. Specially, for a 90 mm precipitation forecast, the Threat score (TS) can increase 6.61% by using the Global Land Data Assimilation System (GLDAS) soil moisture. Secondly, sensitivity experiment results show that the near-surface thermodynamic conditions are more sensitive to dry soil than wet due to the initial moist surface; atmosphere conditions have suppressed the relations between soil and atmosphere; and decreased precipitation can be found over both wet and dry surfaces. Generally, a positive feedback between soil moisture and the near-surface thermodynamic conditions is identified, while the relations between soil moisture and precipitation are quite complicated. This relationship shows a daytime mixing of warm surface soil over dry surfaces and a daytime evaporation of adequate moisture over wet surfaces. The large-scale forcing can affect these relations and finally cause decreased precipitation over both wet and dry surfaces. Full article
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Open AccessArticle
A Multiple Linear Regression Model for Tropical Cyclone Intensity Estimation from Satellite Infrared Images
Atmosphere 2016, 7(3), 40; https://doi.org/10.3390/atmos7030040 - 11 Mar 2016
Cited by 11 | Viewed by 3118
Abstract
An objectively trained model for tropical cyclone intensity estimation from routine satellite infrared images over the Northwestern Pacific Ocean is presented in this paper. The intensity is correlated to some critical signals extracted from the satellite infrared images, by training the 325 tropical [...] Read more.
An objectively trained model for tropical cyclone intensity estimation from routine satellite infrared images over the Northwestern Pacific Ocean is presented in this paper. The intensity is correlated to some critical signals extracted from the satellite infrared images, by training the 325 tropical cyclone cases from 1996 to 2007 typhoon seasons. To begin with, deviation angles and radial profiles of infrared images are calculated to extract as much potential predicators for intensity as possible. These predicators are examined strictly and included into (or excluded from) the initial predicator pool for regression manually. Then, the “thinned” potential predicators are regressed to the intensity by performing a stepwise regression procedure, according to their accumulated variance contribution rates to the model. Finally, the regressed model is verified using 52 cases from 2008 to 2009 typhoon seasons. The R2 and Root Mean Square Error are 0.77 and 12.01 knot in the independent validation tests, respectively. Analysis results demonstrate that this model performs well for strong typhoons, but produces relatively large errors for weak tropical cyclones. Full article
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Open AccessCorrection
Correction: Cooray et al. The Deep Physics Hidden within the Field Expressions of the Radiation Fields of Lightning Return Strokes. Atmosphere, 2016, 7, 21.
Atmosphere 2016, 7(3), 41; https://doi.org/10.3390/atmos7030041 - 10 Mar 2016
Cited by 1 | Viewed by 1566
Abstract
The authors would like to correct the published article [1] as follows.[...] Full article
Open AccessArticle
Characteristics of Preliminary Breakdown Pulses in Positive Ground Flashes during Summer Thunderstorms in Sweden
Atmosphere 2016, 7(3), 39; https://doi.org/10.3390/atmos7030039 - 10 Mar 2016
Cited by 8 | Viewed by 2668
Abstract
This paper presents the characteristics of the preliminary breakdown pulses (PBP) in 51 positive ground flashes recorded during 2014 summer thunderstorms in Sweden. Electric field measurements were conducted remotely using a broadband antenna system (up to 100 MHz) for a recording length of [...] Read more.
This paper presents the characteristics of the preliminary breakdown pulses (PBP) in 51 positive ground flashes recorded during 2014 summer thunderstorms in Sweden. Electric field measurements were conducted remotely using a broadband antenna system (up to 100 MHz) for a recording length of 1 s with 200 ms trigger time. In the analysis, PBP trains were observed in 86% of the cases. Based on the number of trains preceding the first return stroke, the PBP were classified into single and multiple train PBP. Characteristics of the first PBP train were determined and based on the initial polarity of the pulses, three types of PBP were identified. Characteristics of the subsequent PBP trains in the multiple train PBP were also analyzed and they were compared with the first PBP train. Based on the conceptual charge cloud configuration, we found that the inverted dipole is consistent with our observation. We also found that PBP in positive ground flashes during summer thunderstorms in Sweden are weak since the average ratios of the PBP peak to the first return stroke peak lie only between 0.21 and 0.26. Possible reasons for no detection of PBP and the different types of PBP observed were also discussed. Full article
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Open AccessArticle
Effects of Strong East Asian Cold Surges on Improving the Air Quality over Mainland China
Atmosphere 2016, 7(3), 38; https://doi.org/10.3390/atmos7030038 - 10 Mar 2016
Cited by 5 | Viewed by 2719
Abstract
A strong East Asian cold surge (SEACS) is one of the most distinct extreme weather events that can promote an improvement in local air quality. Combining East Asian atmospheric circulation with the air pollution index (API) datasets of 47 major cities throughout mainland [...] Read more.
A strong East Asian cold surge (SEACS) is one of the most distinct extreme weather events that can promote an improvement in local air quality. Combining East Asian atmospheric circulation with the air pollution index (API) datasets of 47 major cities throughout mainland China in 11 winter half-years (November–March) during 2001/2002–2011/2012, we investigated the influence of 39 SEACSs in conjunction with air pollution episodes on air quality over mainland China. The results showed that SEACS can cause considerable improvement in air quality and a remarkable decrease in the API over mainland China in up to 4 days after the SEACS outbreak day. The removal efficiency of air pollutants by SEACSs was greater than 30% in north central China, eastern southwest China, and southeast China. The occurrence date of the lowest value of the local API (indicating the best local air quality) can be observed as late day by day from northwest to southeast over mainland China after the SEACS outbreak, indicating a process of gradual improvement in Chinese air quality after the SEACS outbreak. When clean cold air originating from Siberia moves southward into coastal areas of southeastern China, the increase in sea level pressure, the drop in temperature and the enhancement in the northerly wind also tend to progress gradually from north to south over SEACS-affected East Asia. Thus, the “early in the north and late in the south” feature of air quality improvement by SEACSs over mainland China results from the southward movement of cold air masses from high to low latitudes after cold surge outbreaks. Full article
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Open AccessErratum
Erratum: Feng et al. A Method for Deriving the Boundary Layer Mixing Height from MODIS Atmospheric Profile Data. Atmosphere, 2015, 6, 1346-1361
Atmosphere 2016, 7(3), 37; https://doi.org/10.3390/atmos7030037 - 10 Mar 2016
Cited by 1 | Viewed by 1472
Abstract
The authors would like to correct the acknowledgements of this article [1] as follows:[...] Full article
(This article belongs to the Special Issue Climate Variable Forecasting)
Open AccessArticle
Size-Dependent Characterization of Atmospheric Particles during Winter in Beijing
Atmosphere 2016, 7(3), 36; https://doi.org/10.3390/atmos7030036 - 03 Mar 2016
Cited by 17 | Viewed by 2400
Abstract
Two real-time instruments, NCSA (Nanoparticle Chemical Speciation Analyzer) and ACSA (Aerosol Chemical Speciation Analyzer), were both deployed in Beijing, China to explore the sized-dependent characterization of atmospheric particles. The mass concentrations of PM1, PM2.5, PM10, and sulfate [...] Read more.
Two real-time instruments, NCSA (Nanoparticle Chemical Speciation Analyzer) and ACSA (Aerosol Chemical Speciation Analyzer), were both deployed in Beijing, China to explore the sized-dependent characterization of atmospheric particles. The mass concentrations of PM1, PM2.5, PM10, and sulfate and nitrate in the three size fractions were hourly measured in situ from 13 December 2013 to 7 January 2014. Generally, “sawtooth cycles” are common during winter in Beijing, with the PM concentrations increasing slowly over a few days, then falling to a low level abruptly in only a few hours. The secondary species, sulfate and nitrate, play important roles in haze formation and account for 10.5% and 11.1% of total PM1 mass on average. Based on the variation of PM1 mass concentrations, we classify the study periods into three categories, clean, slightly polluted, and polluted. The oxidation ratios of sulfur and nitrogen both increase from clean to polluted periods, indicating the significant contribution of secondary transformation to haze evolution. While the PM2.5/PM10 ratio shows high dependence on PM pollution level, the ratio of PM1/PM2.5 remains almost stable during the entire study, with an average of 0.90. With respect to the mass-size distribution of chemical components, both sulfate and nitrate show dominant contributions in PM1 size fraction, accounting for 80.7% and 60.3% of total sulfate and nitrate, respectively. Our results also reveal that the elevated sulfate in PM1, and the enhanced nitrate in PM1 and PM2.5–1 size fraction, prompt the formation of haze pollution. Full article
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Open AccessArticle
A Visualization Approach to Air Pollution Data Exploration—A Case Study of Air Quality Index (PM2.5) in Beijing, China
Atmosphere 2016, 7(3), 35; https://doi.org/10.3390/atmos7030035 - 29 Feb 2016
Cited by 18 | Viewed by 6344
Abstract
In recent years, frequent occurrences of significant air pollution events in China have routinely caused panic and are a major topic of discussion by the public and air pollution experts in government and academia. Therefore, this study proposed an efficient visualization method to [...] Read more.
In recent years, frequent occurrences of significant air pollution events in China have routinely caused panic and are a major topic of discussion by the public and air pollution experts in government and academia. Therefore, this study proposed an efficient visualization method to represent directly, quickly, and clearly the spatio-temporal information contained in air pollution data. Data quality check and cleansing during a preliminary visual analysis is presented in tabular form, heat matrix, or line chart, upon which hypotheses can be deduced. Further visualizations were designed to verify the hypotheses and obtain useful findings. This method was tested and validated in a year-long case study of the air quality index (AQI of PM2.5) in Beijing, China. We found that PM2.5, PM10, and NO2 may be emitted by the same sources, and strong winds may accelerate the spread of pollutants. The average concentration of PM2.5 in Beijing was greater than the AQI value of 50 over the six-year study period. Furthermore, arable lands exhibited considerably higher concentrations of air pollutants than vegetation-covered areas. The findings of this study showed that our visualization method is intuitive and reliable through data quality checking and information sharing with multi-perspective air pollution graphs. This method allows the data to be easily understood by the public and inspire or aid further studies in other fields. Full article
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Open AccessArticle
Biophysical Impacts of Land Use Change over North America as Simulated by the Canadian Regional Climate Model
Atmosphere 2016, 7(3), 34; https://doi.org/10.3390/atmos7030034 - 26 Feb 2016
Cited by 4 | Viewed by 2881
Abstract
This study investigates the biophysical impacts of human-induced land use change (LUC) on the regional climate of North America, using the fifth generation Canadian Regional Climate Model (CRCM5). To this end, two simulations are performed with CRCM5 using different land cover datasets, one [...] Read more.
This study investigates the biophysical impacts of human-induced land use change (LUC) on the regional climate of North America, using the fifth generation Canadian Regional Climate Model (CRCM5). To this end, two simulations are performed with CRCM5 using different land cover datasets, one corresponding to the potential vegetation and the other corresponding to current land use, spanning the 1988–2012 period, driven by European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA)-Interim at the lateral boundaries. Comparison of the two suggests higher albedo values, and therefore cooler temperatures, over the LUC regions, in the simulation with LUC, in winter. This is due to the absence of crops in winter, and also possibly due to a snow-mediated positive feedback. Some cooling is observed in summer for the simulation with LUC, mostly due to the higher latent heat fluxes and lower sensible heat fluxes over eastern US. Precipitation changes for these regions are not statistically significant. Analysis of the annual cycles for two LUC regions suggests that the impact of LUC on two meter temperature, evapotranspiration, soil moisture and precipitation are present year round. However, the impact on runoff is mostly restricted to the snowmelt season. This study thus highlights regions and variables most affected by LUC over North America. Full article
(This article belongs to the Special Issue Land Carbon Sequestration and Climate: Present and Future)
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Open AccessArticle
Factors Controlling the Variation of Aerosol Surface Area Concentrations Measured by a Diffusion Charger in Fukuoka, Japan
Atmosphere 2016, 7(3), 33; https://doi.org/10.3390/atmos7030033 - 26 Feb 2016
Cited by 4 | Viewed by 2335
Abstract
The surface area of ambient aerosols can be considered as an index of toxicity because an increased surface area may be able to act as a catalyst for specific reactions between particles and cells, as well as a carrier for co-pollutants, such as [...] Read more.
The surface area of ambient aerosols can be considered as an index of toxicity because an increased surface area may be able to act as a catalyst for specific reactions between particles and cells, as well as a carrier for co-pollutants, such as gases and chemicals. The aerosol surface area concentration was measured together with black carbon (BC) and other chemical species such as organic compounds, sulfate, and nitrate in Fukuoka, Japan, and the effect of the chemical composition of aerosols on their surface area was investigated. Aerosol surface area concentration was highly correlated with BC concentration for the entire period. Day-of-week variation and diurnal variation also showed the strong correlation between aerosol surface area and BC. This implies that even though BC accounts for relatively small percentage (in this study, 3.5%) of PM2.5 mass, it should receive considerable attention when aerosol surface area is considered as an index of adverse health effects caused by exposure of the human body to aerosols. Sulfate aerosol does not usually affect aerosol surface area in Fukuoka, but it may occasionally have a significant effect when the airmass contains an excess amount of relatively smaller particles of sulfate derived from volcanic SO2. Full article
(This article belongs to the Special Issue Air Pollution in the Asia-Pacific Region)
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Open AccessArticle
Dynamics of Dew in a Cold Desert-Shrub Ecosystem and Its Abiotic Controls
Atmosphere 2016, 7(3), 32; https://doi.org/10.3390/atmos7030032 - 25 Feb 2016
Cited by 14 | Viewed by 2187
Abstract
The temporal dynamics of dew formation in cold desert-shrub ecosystems are still poorly understood. We examined dew and its abiotic controls in a shrubland in northwestern China with continuous eddy-covariance measurements of latent heat fluxes gathered over the growing-season of 2012. The dew [...] Read more.
The temporal dynamics of dew formation in cold desert-shrub ecosystems are still poorly understood. We examined dew and its abiotic controls in a shrubland in northwestern China with continuous eddy-covariance measurements of latent heat fluxes gathered over the growing-season of 2012. The dew amount was larger in mid-summer than in spring and autumn, but the dew duration was shorter in summer (from ~10:00 p.m. to ~6:30 a.m.) than in spring and autumn (from ~8:30 p.m. to ~7:30 a.m.). Dew occurred on 85% (166 days) of growing-season days, with monthly means ranging from 0.09 to 0.16 mm day−1. Dew was dominantly and positively controlled by Relative Humidity (RH), which explained 89% of its variation. Soil heat flux (G), air temperature (Ta), wind speed (Ws), Soil Water Content (SWC) and Vapor Pressure Deficit (VPD) also influenced dew formation. The most favorable conditions for dew formation were at Ta < 17 °C and RH > 75%. The Penman–Monteith equation predicted actual dew reasonably well. The predicted growing-season dew amount (21.3 mm) was equivalent to 7.2% and 8.9% of corresponding rainfall and evapotranspiration, respectively. It is suggested that dew could be a stable and continuous source of water that helps desert plants survive during warm summers. Full article
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Open AccessArticle
Characterization of Fine Particulate Matter Emitted from the Resuspension of Road and Pavement Dust in the Metropolitan Area of São Paulo, Brazil
Atmosphere 2016, 7(3), 31; https://doi.org/10.3390/atmos7030031 - 23 Feb 2016
Cited by 17 | Viewed by 2654
Abstract
Many studies have been performed in order to characterize the sources of airborne particles in the Metropolitan Area of São Paulo (MASP), in Brazil. Those studies have been based on receptor modeling and most of the uncertainties in their results are related to [...] Read more.
Many studies have been performed in order to characterize the sources of airborne particles in the Metropolitan Area of São Paulo (MASP), in Brazil. Those studies have been based on receptor modeling and most of the uncertainties in their results are related to the emission profile of the resuspended road dust particles. In this study, we analyzed the composition of resuspended road dust particles in different environments: local streets, paved roads inside traffic tunnels, and high traffic streets. We analyzed the samples to quantify the concentrations of trace elements and black carbon. On the basis of that analysis, we developed emission profiles of the resuspended road dust that are representative of the different types of urban pavement in the MASP. This study is important given the international efforts in improving emissions factors with local characteristics, mainly in South America and other regions for which there is a lack of related information. This work presents emission profiles derived from resuspended road dust samples that are representative of the different types of urban pavement in the Metropolitan Area of São Paulo. Full article
(This article belongs to the Special Issue Atmospheric Composition Observations) Printed Edition available
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