Research

Jump to: Other

6296 KiB

Open AccessArticle

Irradiance Impact on Pollution by Integrating Nephelometer Measurements

by Maria Rita Perrone, Pasquale Burlizzi and Salvatore Romano

Atmosphere 2015, 6(12), 1889-1903; https://0-doi-org.brum.beds.ac.uk/10.3390/atmos6121836 - 08 Dec 2015

Cited by 3 | Viewed by 5002

Three-wavelength integrating nephelometer measurements combined with short- (SW) and long-wave (LW) irradiance measurements were used to investigate the irradiance effects on the daily evolution of the particulate matter (PM) at the ground level, and contribute to the characterization of the land–atmosphere interaction in [...] Read more.

Three-wavelength integrating nephelometer measurements combined with short- (SW) and long-wave (LW) irradiance measurements were used to investigate the irradiance effects on the daily evolution of the particulate matter (PM) at the ground level, and contribute to the characterization of the land–atmosphere interaction in pollution dispersal. The integrating nephelometer measurements have allowed characterizing the daily changes of the PM optical and microphysical properties by the aerosol scattering coefficient (σ_p) and the scattering Ångström coefficient (å). We found that on a daily basis σ_p reached the minimum values when the irradiance reached the maximum values, since the convective motions, which favor the particle dispersion at the surface, increase with the irradiance. The å value, which is commonly used as qualitative indicator of the dominant particle size, has allowed evaluating the irradiance effects on the mean particle size distribution at the surface and revealed that the irradiance increase favors mainly the dispersion of the ground-level fine particles. Particle size-distribution measurements supported the last comment. Measurements were performed from 4 to 10 May 2015 when the study site was affected by a Saharan dust outbreak, to also evaluate the impact of long-range transported particles on the daily evolution of the ground-level particle’s properties and the SW and LW irradiance. Full article

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

► Show Figures

Graphical abstract

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://0-doi-org.brum.beds.ac.uk/10.3390/atmos6101578 - 23 Oct 2015

Cited by 13 | Viewed by 5609

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)

► Show Figures

Figure 1

1878 KiB

Open AccessArticle

Characteristics of Gravity Waves over an Antarctic Ice Sheet during an Austral Summer

by Daniela Cava, Umberto Giostra and Gabriel Katul

Atmosphere 2015, 6(9), 1271-1289; https://0-doi-org.brum.beds.ac.uk/10.3390/atmos6091271 - 25 Aug 2015

Cited by 21 | Viewed by 4950

Abstract

While occurrences of wavelike motion in the stable boundary layer due to the presence of a significant restoring buoyancy force are rarely disputed, their modalities and interaction with turbulence remain a subject of active research. In this work, the characteristics of gravity waves [...] Read more.

While occurrences of wavelike motion in the stable boundary layer due to the presence of a significant restoring buoyancy force are rarely disputed, their modalities and interaction with turbulence remain a subject of active research. In this work, the characteristics of gravity waves and their impact on flow statistics, including turbulent fluxes, are presented using data collected above an Antarctic Ice sheet during an Austral Summer. Antarctica is an ideal location for exploring the characteristics of gravity waves because of persistent conditions of strong atmospheric stability in the lower troposphere. Periods dominated by wavelike motion have been identified by analysing time series measured by fast response instrumentation. The nature and characteristic of the dominant wavy motions are investigated using Fourier cross-spectral indicators. Moreover, a multi-resolution decomposition has been applied to separate gravity waves from turbulent fluctuations in case of a sufficiently defined spectral gap. Statistics computed after removing wavy disturbances highlight the large impact of gravity waves on second order turbulent quantities including turbulent flux calculations. Full article

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

► Show Figures

Graphical abstract

4538 KiB

Open AccessArticle

Case Study of Particle Number Fluxes and Size Distributions during Nucleation Events in Southeastern Italy in the Summer

by Marianna Conte, Antonio Donateo, Adelaide Dinoi, Franco Belosi and Daniele Contini

Atmosphere 2015, 6(7), 942-959; https://0-doi-org.brum.beds.ac.uk/10.3390/atmos6070942 - 14 Jul 2015

Cited by 13 | Viewed by 5396

Abstract

Concentrations, size distributions and particle number vertical turbulent fluxes were measured by the eddy-covariance method at an urban background site in southeastern Italy during the summer. CO2/H2O concentrations and fluxes were also determined together with meteorological parameters. Time series show that particles could [...] Read more.

Concentrations, size distributions and particle number vertical turbulent fluxes were measured by the eddy-covariance method at an urban background site in southeastern Italy during the summer. CO2/H2O concentrations and fluxes were also determined together with meteorological parameters. Time series show that particles could be divided into two size classes with negatively-correlated temporal trends in diurnal hours: nanoparticles (diameter Dp < 50 nm) and larger particles (Dp > 50 nm). Larger particles include part of the Aitken mode and the accumulation mode. Nanoparticles peaked in diurnal hours due to the presence of several days with nucleation events when particles Dp > 50 nm were at minimum concentrations. Nucleation increased diurnal total particle concentration by a factor of 2.5, reducing mean and median diameters from Dmean = 62.3 ± 1.2 nm and Dmedian = 29.1 ± 1.3 nm on non-event days to Dmean = 35.4 ± 0.6 nm and Dmedian = 15.5 ± 0.3 nm on event days. During nucleation events, particle deposition increased markedly (i.e., downward fluxes), but no significant changes in CO2 concentrations and fluxes were observed. This is compatible with new particle formation above the measurement height and a consequent net transport towards the surface. Correlation with meteorology shows that the formation of new particles is correlated with solar radiation and favored at high wind velocity. Full article

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

► Show Figures

Graphical abstract

603 KiB

Open AccessArticle

Land-Atmosphere Transfer Parameters in the Brazilian Pantanal during the Dry Season

by Paolo Martano, Edson Pereira Marques Filho and Leonardo Deane De Abreu Sá

Atmosphere 2015, 6(6), 805-821; https://0-doi-org.brum.beds.ac.uk/10.3390/atmos6060805 - 10 Jun 2015

Cited by 1 | Viewed by 4515

Abstract

The Brazilian region of Pantanal is one of the largest wetlands in the world, characterized by a wet season, in which it is covered by a shallow water layer, and a dry season, in which the water layer disappears. The aim of this [...] Read more.

The Brazilian region of Pantanal is one of the largest wetlands in the world, characterized by a wet season, in which it is covered by a shallow water layer, and a dry season, in which the water layer disappears. The aim of this study is the estimation of the main parameters (drag coefficients and surface scale lengths) involved in modelling the surface atmosphere transfer of momentum, heat and water vapor from the dataset of the second Interdisciplinary Pantanal Experiment (IPE2). The roughness parameters and the stability correction parameters have been estimated in the framework of the similarity theory for the vertical profiles of wind speed and temperature. Thus, a previously-developed methodology was adapted to the available dataset from the IPE2 five-level mast. The results are in reasonable agreement with the available literature. An attempt to obtain the scalar transfer parameters for water vapor has been performed by a Penman–Monteith approach using a two-component surface resistance in parallel between a vegetation and a bare soil part. The parameters of the model have been calibrated using a non-linear regression method. The scalar drag coefficient retrieved in this way is in agreement with that calculated by the flux-gradient approach for the sensible heat flux. Eventually, an evaluation of the vegetation contribution to the total vapor flux is given. Full article

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

► Show Figures

Figure 1

5498 KiB

Open AccessArticle

The Concentrations and Reduction of Airborne Particulate Matter (PM₁₀, PM_2.5, PM₁) at Shelterbelt Site in Beijing

by Jungang Chen, Xinxiao Yu, Fenbing Sun, Xiaoxiu Lun, Yanlin Fu, Guodong Jia, Zhengming Zhang, Xuhui Liu, Li Mo and Huaxing Bi

Atmosphere 2015, 6(5), 650-676; https://0-doi-org.brum.beds.ac.uk/10.3390/atmos6050650 - 18 May 2015

Cited by 47 | Viewed by 8569

Abstract

Particulate matter is a serious source of air pollution in urban areas, where it exerts adverse effects on human health. This article focuses on the study of subduction of shelterbelts for atmospheric particulates. The results suggest that (1) the PM mass concentration is [...] Read more.

Particulate matter is a serious source of air pollution in urban areas, where it exerts adverse effects on human health. This article focuses on the study of subduction of shelterbelts for atmospheric particulates. The results suggest that (1) the PM mass concentration is higher in the morning or both morning and noon inside the shelterbelts and lower mass concentrations at other times; (2) the particle mass concentration inside shelterbelt is higher than outside; (3) the particle interception efficiency of the two forest belts over the three months in descending order was PM10 > PM1 > PM2.5; and (4) the two shelterbelts captured air pollutants at rates of 1496.285 and 909.075 kg/month and the major atmospheric pollutant in Beijing city is PM10. Future research directions are to study PM mass concentration variation of shelterbelt with different tree species and different configuration. Full article

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

► Show Figures

Figure 1

1470 KiB

Open AccessArticle

Evapotranspiration Estimates over Non-Homogeneous Mediterranean Land Cover by a Calibrated “Critical Resistance” Approach

by Paolo Martano

Atmosphere 2015, 6(3), 255-272; https://0-doi-org.brum.beds.ac.uk/10.3390/atmos6030255 - 27 Feb 2015

Cited by 6 | Viewed by 5242

Abstract

An approach based on the Penman-Monteith equation was used to estimate the actual evapotranspiration from local meteorological data over non-homogeneous land cover in a Mediterranean site in the south-east of Italy, with two six month data sets from two different years of measurements [...] Read more.

An approach based on the Penman-Monteith equation was used to estimate the actual evapotranspiration from local meteorological data over non-homogeneous land cover in a Mediterranean site in the south-east of Italy, with two six month data sets from two different years of measurements (2006 and 2009). The “critical resistance” formulation was used in different forms to model the surface resistance, together with some modifications to take into account the soil moisture content. One, two, or three model parameters were estimated, one of them related to the atmospheric resistance and the others to the surface resistance, and the calibration was made by either linear regression or nonlinear minimization of a proper cost function, depending on the applicability. Two kinds of cost functions were tested, the first depending on both the latent heat flux and the difference between screen air temperature and surface radiometric temperature, and the second depending on the temperature difference only. In all cases the calculated fluxes give better results with respect to both a flux-gradient approach and a complementarity based method, that require comparable data inputs. However the calibration by the temperature differences only, that requires no turbulent flux measurements, considerably increases the statistical uncertainty of the calibration parameters. The inclusion of the soil moisture did not significantly improve the model results in the considered site. Full article

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

► Show Figures

Figure 1

1452 KiB

Open AccessArticle

Characteristics and Sources of Metals in TSP and PM_2.5 in an Urban Forest Park at Guangzhou

by Yi-Hua Xiao, Shi-Rong Liu, Fu-Chun Tong, Yuan-Wen Kuang, Bu-Feng Chen and Yue-Dong Guo

Atmosphere 2014, 5(4), 775-787; https://0-doi-org.brum.beds.ac.uk/10.3390/atmos5040775 - 28 Oct 2014

Cited by 24 | Viewed by 6775

Abstract

Urban forest parks play important roles in improving environments, protecting biodiversity and even public welfare. Aerosols, including total suspended particles (TSP) and particulate matter with aerodynamic diameter less than 2.5 µm (PM_2.5), were simultaneously collected in an urban forest park [...] Read more.

Urban forest parks play important roles in improving environments, protecting biodiversity and even public welfare. Aerosols, including total suspended particles (TSP) and particulate matter with aerodynamic diameter less than 2.5 µm (PM_2.5), were simultaneously collected in an urban forest park (Dafushan) at Guangzhou, southern China, from January 2012 to December 2013. The concentrations of 12 metals (Al, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Se, and Zn) in both TSP and PM_2.5 were quantified using an inductively coupled plasma-mass spectrometer. The origins and possible sources of the studied metals in the PM_2.5 and TSP were evaluated using the crustal enrichment factors and the principal component analysis, respectively. The results showed that Dafushan urban forest park was polluted by PM_2.5 rather than by TSP. The PM_2.5 and TSP in the forest park exhibited seasonal patterns with significantly higher contents in the dry season compared with the rainy season. The metals Al, Zn, Pb were the most abundant, while Hg was the lowest metals in the aerosols. The ratios of PM_2.5/TSP ratio indicated that the metals were predominant in the finer particles (PM_2.5). The crustal enrichment factors indicated that Cd, Cu, Mo, Pb, Se and Zn in the aerosols originated from anthropogenic sources, while Al and Mn were mainly of crustal origin. The principal component analysis implied that industrial activities, traffic-related emissions, and soil dust were the main possible sources of the metals in both PM_2.5 and TSP in Dafushan forest park. Full article

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

► Show Figures

Figure 1

Other

Jump to: Research

904 KiB

Open AccessLetter

Scaling Flux Tower Observations of Sensible Heat Flux Using Weighted Area-to-Area Regression Kriging

by Maogui Hu, Jianghao Wang, Yong Ge, Mengxiao Liu, Shaomin Liu, Ziwei Xu and Tongren Xu

Atmosphere 2015, 6(8), 1032-1044; https://0-doi-org.brum.beds.ac.uk/10.3390/atmos6081032 - 24 Jul 2015

Cited by 17 | Viewed by 5117

Abstract

Sensible heat flux (H) plays an important role in characterizations of land surface water and heat balance. There are various types of H measurement methods that depend on observation scale, from local-area-scale eddy covariance (EC) to regional-scale large aperture scintillometer (LAS) and remote [...] Read more.

Sensible heat flux (H) plays an important role in characterizations of land surface water and heat balance. There are various types of H measurement methods that depend on observation scale, from local-area-scale eddy covariance (EC) to regional-scale large aperture scintillometer (LAS) and remote sensing (RS) products. However, methods of converting one H scale to another to validate RS products are still open for question. A previous area-to-area regression kriging-based scaling method performed well in converting EC-scale H to LAS-scale H. However, the method does not consider the path-weighting function in the EC- to LAS-scale kriging with the regression residue, which inevitably brought about a bias estimation. In this study, a weighted area-to-area regression kriging (WATA RK) model is proposed to convert EC-scale H to LAS-scale H. It involves path-weighting functions of EC and LAS source areas in both regression and area kriging stages. Results show that WATA RK outperforms traditional methods in most cases, improving estimation accuracy. The method is considered to provide an efficient validation of RS H flux products. Full article

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

► Show Figures