Atmosphere

1138 KiB

Open AccessCommunication

Radiation Balance of Urban Materials and Their Thermal Impact in Semi-Desert Region: Mexicali, México Study Case

by Néstor Santillán-Soto, Rafael García-Cueto, Zalia Haro-Rincón, Sara Ojeda-Benítez, Margarito Quintero-Núñez and Nicolás Velázquez-Limón

Atmosphere 2015, 6(10), 1578-1589; https://doi.org/10.3390/atmos6101578 - 23 Oct 2015

Cited by 13 | Viewed by 5606

Abstract

Net radiation is an essential forcing of climate in the lower layers of Earth’s atmosphere. In this paper, radiation balance is measured in clay soil and green grass, and is compared with three urban materials. These materials: asphalt, concrete and white painted elastomeric [...] Read more.

Net radiation is an essential forcing of climate in the lower layers of Earth’s atmosphere. In this paper, radiation balance is measured in clay soil and green grass, and is compared with three urban materials. These materials: asphalt, concrete and white painted elastomeric polystyrene roofing sheet are widely used in Mexicali, Baja California, México. This study was carried out during August of 2011, the hottest time of the year. The 24-hour average values of net radiation found were: 137.2 W·m⁻² for asphalt, 119.1 for concrete, 104.6 for clay soil, 152 for green grass and 29.2 for the polystyrene insulation. The latter two types of materials are likely to be the most effective in reducing urban heat island effects. This variation in the radiation balance has widespread implications for human living conditions, as land cover change tends to be towards surfaces that have higher levels of net radiation. Full article

(This article belongs to the Special Issue Land-Atmosphere Interaction in Micrometeorology and Pollution Dispersal)

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2795 KiB

Open AccessArticle

Radar Estimation of Intense Rainfall Rates through Adaptive Calibration of the Z-R Relation

by Andrea Libertino, Paola Allamano, Pierluigi Claps, Roberto Cremonini and Francesco Laio

Atmosphere 2015, 6(10), 1559-1577; https://doi.org/10.3390/atmos6101559 - 22 Oct 2015

Cited by 20 | Viewed by 5905

Abstract

Rainfall intensity estimation from weather radar is still significantly uncertain, due to local anomalies, radar beam attenuation, inappropriate calibration of the radar reflectivity factor (Z) to rainfall rate (R) relationship, and sampling errors. The aim of this work is [...] Read more.

Rainfall intensity estimation from weather radar is still significantly uncertain, due to local anomalies, radar beam attenuation, inappropriate calibration of the radar reflectivity factor (Z) to rainfall rate (R) relationship, and sampling errors. The aim of this work is to revise the use of the power-law equation commonly adopted to relate radar reflectivity and rainfall rate to increase the estimation quality in the presence of intense rainfall rates. We introduce a quasi real-time procedure for an adaptive in space and time estimation of the Z-R relation. The procedure is applied in a comprehensive case study, which includes 16 severe rainfall events in the north-west of Italy. The study demonstrates that the technique outperforms the classical estimation methods for most of the analysed events. The determination coefficient improves by up to 30% and the bias values for stratiform events decreases by up to 80% of the values obtained with the classical, non-adaptive, Z-R relations. The proposed procedure therefore shows significant potential for operational uses. Full article

(This article belongs to the Special Issue Radar Meteorology)

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812 KiB

Open AccessArticle

Research on the Coupling Coordination Relationship between Urbanization and the Air Environment: A Case Study of the Area of Wuhan

by Lei Ding, Weituo Zhao, Yalin Huang, Shenggao Cheng and Chao Liu

Atmosphere 2015, 6(10), 1539-1558; https://doi.org/10.3390/atmos6101539 - 22 Oct 2015

Cited by 102 | Viewed by 8199

Abstract

China’s high-speed socioeconomic development has been characterized by rapid urbanization and a series of ecological environment issues, especially air pollution. This paper proposed a comprehensive indicator system for the evaluation of urbanization and the air environment in Wuhan, a metropolis in central China, [...] Read more.

China’s high-speed socioeconomic development has been characterized by rapid urbanization and a series of ecological environment issues, especially air pollution. This paper proposed a comprehensive indicator system for the evaluation of urbanization and the air environment in Wuhan, a metropolis in central China, and then investigated the relationship between urbanization and the air environment from the perspective of coupling coordination theory. Furthermore, a coupling coordination degree model (CCDM) was constructed to estimate the relationship by using panel data collected from 1996–2013. The results showed the following: (1) Spatial urbanization and air environment quality make the greatest contributions to the compound system compared to other first grade indicators, indicating that they are critical factors to consider when the government is making relevant decisions about urban sprawl. (2) The comprehensive level of the air environment initially decreased from 1996–1998 and then increased with fluctuations in Wuhan, with several inflection points, meaning that the variation process of the air environment is unstable and repetitive, and efforts to improve the air environment must persist over a long period of time. Lastly, (3) the degree of coordinated coupling between urbanization and the air environment exhibited an S-shaped curve, indicating that Wuhan changed from having slightly unbalanced development to barely balanced development and then entered into a period of superiorly balanced development, with the air environment lagging. Thus, the ambient urban air quality has been subject to great pressure, and the government should continue to take effective action to improve it. Full article

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3103 KiB

Open AccessArticle

Optical Properties of Fine Particulate Matter in Upper Silesia, Poland

by Jozef S. Pastuszka, Wioletta Rogula-Kozłowska, Krzysztof Klejnowski and Patrycja Rogula-Kopiec

Atmosphere 2015, 6(10), 1521-1538; https://doi.org/10.3390/atmos6101521 - 20 Oct 2015

Cited by 5 | Viewed by 4162

Abstract

Ambient particles whose aerodynamic diameters were not greater than 2.5 µm (fine fraction of Particulate Matter; PM_2.5) and 1 µm (PM₁; sub-fraction of PM_2.5) were sampled at three sites in Upper Silesia (Poland): urban background site, rural [...] Read more.

Ambient particles whose aerodynamic diameters were not greater than 2.5 µm (fine fraction of Particulate Matter; PM_2.5) and 1 µm (PM₁; sub-fraction of PM_2.5) were sampled at three sites in Upper Silesia (Poland): urban background site, rural background site, and urban traffic site. In total, 240 samples were collected between 2 August 2009 and 27 December 2010. The reflectance of the collected PM₁ and PM_2.5samples was determined with a digital smoke stain reflectometer. The 24-h courses and seasonal changes of three determined optical parameters for PM₁ and PM_2.5 (absorption coefficient (a), mass absorption (σ), and mean light reflection coefficient (R_av)) were illustrated and discussed. The mean values of the regional background absorption coefficient (a) were 1.27 × 10⁻⁵ m⁻¹ and 0.87 × 10⁻⁵ m⁻¹ for PM_2.5 and PM₁, respectively. In Katowice (urban background), the mean absorption levels were 2.37 × 10⁻⁵ m⁻¹ and 2.09 × 10⁻⁵ m⁻¹ for PM_2.5 and PM₁, respectively. The highest values of the absorption coefficient for both PM fractions were found close to the highway (urban traffic site). In the heating season (winter), the absorption coefficient (a) for PM_2.5 and PM₁ increased significantly when compared with the non-heating season. The obtained results confirmed the thesis about the significant increase in the elemental PM_2.5-bound carbon concentration caused by the intensified hard coal combustion in Upper Silesia in winter. Moreover, it turned out that the increase in the concentration of the PM_2.5-bound sulphates was even higher, which resulted in the relative decrease of the elemental carbon content in this PM fraction in some areas. Consequently, the mass absorption value dropped there as well. Full article

(This article belongs to the Special Issue Atmospheric Aerosols and Their Radiative Effects)

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1171 KiB

Open AccessArticle

Combining DMSP/OLS Nighttime Light with Echo State Network for Prediction of Daily PM_2.5 Average Concentrations in Shanghai, China

by Zhao Xu, Xiaopeng Xia, Xiangnan Liu and Zhiguang Qian

Atmosphere 2015, 6(10), 1507-1520; https://doi.org/10.3390/atmos6101507 - 19 Oct 2015

Cited by 23 | Viewed by 5196

Abstract

The objective of this study is to investigate the potential of nighttime light data, acquired with Defense Meteorological Satellite Program Operational Linescan System (DMSP/OLS) owned by National Oceanic and Atmospheric Administration (NOAA), in predicting urban daily particulate matter (PM)_2.5 with an aerodynamic [...] Read more.

The objective of this study is to investigate the potential of nighttime light data, acquired with Defense Meteorological Satellite Program Operational Linescan System (DMSP/OLS) owned by National Oceanic and Atmospheric Administration (NOAA), in predicting urban daily particulate matter (PM)_2.5 with an aerodynamic diameter of less than 2.5 µm average concentrations. To achieve the purpose, we firstly extracted two night light indices, the Nighttime Light Intensity Index (NLII) and the Nighttime Saturated Light Area Index (NSLAI) from DMSP/OLS images. Through Gaussian fitting of the relationship between the indices and the daily PM_2.5 concentrations data released by the government, we found that the intraday nighttime light indices were all more relevant with the PM_2.5 average concentrations of the next day in Shanghai. Therefore, the 56 sets of data, the light indices were collected from 3 November 2013 to 28 December 2013, the daily PM_2.5 concentrations data were collected from 4 November 2013 to 29 December 2013, and these were divided into two parts. The first 40 sets were used for training the model of echo state network (ESN). The last 16 sets were used for testing. The value of R² of predicted results was as high as 0.6318. In summary, the effectiveness of nighttime light data that used for the prediction of urban daily PM_2.5 average concentrations was verified in this study. Full article

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533 KiB

Open AccessArticle

Inland Concentrations of Cl₂ and ClNO₂ in Southeast Texas Suggest Chlorine Chemistry Significantly Contributes to Atmospheric Reactivity

by Cameron B. Faxon, Jeffrey K. Bean and Lea Hildebrandt Ruiz

Atmosphere 2015, 6(10), 1487-1506; https://doi.org/10.3390/atmos6101487 - 14 Oct 2015

Cited by 55 | Viewed by 8660

Abstract

Measurements of molecular chlorine (Cl₂), nitryl chloride (ClNO₂), and dinitrogen pentoxide (N₂O₅) were taken as part of the DISCOVER-AQ Texas 2013 campaign with a High Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS) using iodide (I-) [...] Read more.

Measurements of molecular chlorine (Cl₂), nitryl chloride (ClNO₂), and dinitrogen pentoxide (N₂O₅) were taken as part of the DISCOVER-AQ Texas 2013 campaign with a High Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS) using iodide (I-) as a reagent ion. ClNO₂ concentrations exceeding 50 ppt were regularly detected with peak concentrations typically occurring between 7:00 a.m. and 10:00 am. Hourly averaged Cl₂ concentrations peaked daily between 3:00 p.m. and 4:00 p.m., with a 29-day average of 0.9 ± 0.3 (1σ) ppt. A day-time Cl₂ source of up to 35 ppt∙h⁻¹ is required to explain these observations, corresponding to a maximum chlorine radical (Cl^•) production rate of 70 ppt∙h⁻¹. Modeling of the Cl₂ source suggests that it can enhance daily maximum O₃ and RO₂^•concentrations by 8%–10% and 28%–50%, respectively. Modeling of observed ClNO₂ assuming a well-mixed nocturnal boundary layer indicates O₃ and RO₂^• enhancements of up to 2.1% and 38%, respectively, with a maximum impact in the early morning. These enhancements affect the formation of secondary organic aerosol and compliance with air quality standards for ozone and particulate matter. Full article

(This article belongs to the Special Issue Atmospheric Composition Observations)

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1591 KiB

Open AccessArticle

Long-Term Trend and Seasonal Variability of Horizontal Visibility in Nigerian Troposphere

by Mukhtar Balarabe, Khiruddin Abdullah and Mohd Nawawi

Atmosphere 2015, 6(10), 1462-1486; https://doi.org/10.3390/atmos6101462 - 02 Oct 2015

Cited by 12 | Viewed by 6752

Abstract

A study of the long-term variability; trend and characteristics of visibility in four zones of Nigeria was carried out. Visibility and other meteorological data from NOAA-NCDC and aerosol index data over Nigeria during 1984–2013 are analyzed using time series and simple regression model. [...] Read more.

A study of the long-term variability; trend and characteristics of visibility in four zones of Nigeria was carried out. Visibility and other meteorological data from NOAA-NCDC and aerosol index data over Nigeria during 1984–2013 are analyzed using time series and simple regression model. There are significant decreasing trends for every region and season during the 30-years period; the fluctuations exhibited nearly similar pattern. The 30-year mean visibilities for the four zones (Sahel; North Central; Southern; and Coastal) were 13.8 ± 3.9; 14.3 ± 4.2; 13.6 ± 3.5 and 12.8 ± 3.1 km with decreasing trends at the rates of 0.08; 0.06; 0.02 and 0.02 km/year. In all the zones; visibilities were better in summer while worse in Harmattan (dry season). During summer visibility was best in Sahel and North-central; however; in Harmattan visibility was best in southern and coastal zones. It was best between May and June (17.6; 18.9; 16.6 and 15.1 km) with a second peak in September. The 30-year seasonal averages were 16.2 ± 2.1; 16.8 ± 2.4; 15.4 ± 1.8 and 14.0 ± 2.2 km in summer; and 10.2 ± 2.5; 10.9 ± 2.9; 11.0 ± 3.3 and 11.4 ± 3.0 km in Harmattan for the respective zones. Sahel and North Central had the worse visibility reduction during Harmattan compared with Southern and coastal areas. An analysis based on simple regression equation reveals a strong and negative relationship between visibility on one hand; AI; and AOD on the other hand. The analysis also discusses the variability regarding the frequency of occurrence of a dust storm; dust haze; and good visibility over the period of study. Full article

(This article belongs to the Special Issue Atmospheric Aerosols and Their Radiative Effects)

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1132 KiB

Open AccessArticle

Ultrafine Particles in Residential Indoors and Doses Deposited in the Human Respiratory System

by Maurizio Manigrasso, Ettore Guerriero and Pasquale Avino

Atmosphere 2015, 6(10), 1444-1461; https://doi.org/10.3390/atmos6101444 - 30 Sep 2015

Cited by 22 | Viewed by 5550

Abstract

Indoor aerosol sources may significantly contribute to the daily dose of particles deposited into the human respiratory system. Therefore, it is important to characterize the aerosols deriving from the operations currently performed in an indoor environment and also to estimate the relevant particle [...] Read more.

Indoor aerosol sources may significantly contribute to the daily dose of particles deposited into the human respiratory system. Therefore, it is important to characterize the aerosols deriving from the operations currently performed in an indoor environment and also to estimate the relevant particle respiratory doses. For this aim, aerosols from indoor combustive and non-combustive sources were characterized in terms of aerosol size distributions, and the relevant deposition doses were estimated as a function of time, particle diameter and deposition site in the respiratory system. Ultrafine particles almost entirely made up the doses estimated. The maximum contribution was due to particles deposited in the alveolar region between the 18th and the 21st airway generation. When cooking operations were performed, respiratory doses per unit time were about ten-fold higher than the relevant indoor background dose. Such doses were even higher than those associated with outdoor traffic aerosol. Full article

(This article belongs to the Special Issue Indoor and Outdoor Air Quality)

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1366 KiB

Open AccessArticle

Chemical Composition of Indoor and Outdoor PM_2.5 in Three Schools in the City of Rome

by Luca Tofful and Cinzia Perrino

Atmosphere 2015, 6(10), 1422-1443; https://doi.org/10.3390/atmos6101422 - 30 Sep 2015

Cited by 30 | Viewed by 5837

Abstract

In Italy, children spend up to 30% of their time in school institutions; for this reason, the evaluation of indoor air quality in schools constitutes a necessary step forward in the direction of child health protection. In this study, we investigated the [...] Read more.

In Italy, children spend up to 30% of their time in school institutions; for this reason, the evaluation of indoor air quality in schools constitutes a necessary step forward in the direction of child health protection. In this study, we investigated the chemical composition of PM_2.5 collected simultaneously indoor and outdoor in three primary schools in Rome. Seasonal variations between winter and spring/summer were evaluated, as well as the role of the main macro-sources of PM (soil, sea, traffic, secondary inorganics and organics). During winter periods, characterized by strong atmospheric stability, the main contributors were organics and combustion products, which accounted for more than 70% of the total mass both indoor and outdoor. Spring/summer period was characterized by very low outdoor concentrations (12 μg/m³ on average) and by a more balanced contribution of organic, traffic and secondary inorganic components. Indoor, the contribution of soil-related species from re-suspension of settled dust and secondary inorganic species from outdoor photochemical reactions became significant. Given that several indoor exceedances of the international air quality standards for PM_2.5 were recorded during the most polluted days, the infiltration of outdoor air, due to the inadequate construction characteristics of the buildings and the absence of automated air filtration systems, seemed to be the main causes of the high PM concentrations measured indoor. Full article

(This article belongs to the Special Issue Indoor and Outdoor Air Quality)

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1425 KiB

Open AccessArticle

Temporal-Spatial Variation of Drought Indicated by SPI and SPEI in Ningxia Hui Autonomous Region, China

by Chunping Tan, Jianping Yang and Man Li

Atmosphere 2015, 6(10), 1399-1421; https://doi.org/10.3390/atmos6101399 - 30 Sep 2015

Cited by 176 | Viewed by 11577

Abstract

The Ningxia Hui Autonomous Region of China (Ningxia) is an important food production area in northwest China severely affected by drought. The Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) were calculated based on monthly meteorological data to explore climate change [...] Read more.

The Ningxia Hui Autonomous Region of China (Ningxia) is an important food production area in northwest China severely affected by drought. The Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) were calculated based on monthly meteorological data to explore climate change and variation in drought intensity, duration, frequency, and spatial extent in Ningxia during 1972–2011. Results show that the SPEI is more applicable than the SPI for exploring climate change and drought variation in Ningxia. The Ningxia climate experienced a significant drying tendency. Annual SPEI decreased about 0.37 decade⁻¹ during 1972–2011. Drought was exacerbated by this drying tendency. Regional average duration, maximum duration, intensity, and frequency of drought identified by the SPEI increased by one month, three months, 0.15%, and 36.1%, respectively, during 1992–2011 compared to the period of 1972–1991. The spatial extent of drought identified by the SPEI increased about 14.4% decade⁻¹ in the spring during 1972–2011. Spatially, drought frequency increased from north to south. Average intensity (maximum duration) of drought calculated by the SPEI increased (decreased) northward and southward from the central arid area. Full article

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Atmosphere, Volume 6, Issue 10 (October 2015) – 10 articles , Pages 1399-1589

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