Atmosphere

870 KiB

Open AccessArticle

Characteristics of Carbonaceous Species in PM2.5 in Wanzhou in the Hinterland of the Three Gorges Reservior of Northeast Chongqing, China

by Liuyi Zhang, Yimin Huang, Yuan Liu, Fumo Yang, Guoxin Lan, Chuan Fu and Jun Wang

Atmosphere 2015, 6(4), 534-546; https://doi.org/10.3390/atmos6040534 - 13 Apr 2015

Cited by 20 | Viewed by 6129

Abstract

Daily PM2.5 samples were collected in the four consecutive seasons in 2013 in Wanzhou, the second largest city in Chongqing Municipality of China and in the hinterland of the Three Gorges Reservior on Yangtze River and analyzed for the mass concentrations and carbonaceous [...] Read more.

Daily PM2.5 samples were collected in the four consecutive seasons in 2013 in Wanzhou, the second largest city in Chongqing Municipality of China and in the hinterland of the Three Gorges Reservior on Yangtze River and analyzed for the mass concentrations and carbonaceous species of PM2.5 to investigate the abundance and seasonal characteristics of PM2.5, and organic carbon (OC) and elemental carbon (EC). The annual average PM2.5 concentrations were 125.3 μg·m⁻³, while OC and EC were 23.6 μg·m⁻³ and 8.7 μg·m⁻³, respectively. The total carbonaceous aerosol (TCA) accounted for 32.6% of the PM2.5 mass. On seasonal average, the OC and EC concentrations ranked in the order of winter > fall > spring > summer, which could be attributed to the combined effects of changes in local emissions and seasonal meteorological conditions. Strong OC-EC correlations were found in the winter and fall, suggesting the contributions of similar sources. The lowest OC-EC correlation occurred in the summer, probably due to the increases in biogenic emission and formation of secondary organic aerosol (SOA) through photochemical activity. Average secondary organic carbon (SOC) concentration was 9.0 μg·m⁻³, accounting for 32.3% of the total OC. The average ratios of SOA/PM2.5 of 3.8%~15.7% indicated that SOA was a minor fraction in fine particles of Wanzhou. Full article

(This article belongs to the Special Issue Sources, Formation and Impacts of Secondary Aerosol)

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933 KiB

Open AccessArticle

Long-Term Measurement for Low-Tropospheric Water Vapor and Aerosol by Raman Lidar in Wuhan

by Wei Wang, Wei Gong, Feiyue Mao and Jinye Zhang

Atmosphere 2015, 6(4), 521-533; https://doi.org/10.3390/atmos6040521 - 3 Apr 2015

Cited by 19 | Viewed by 6255

Abstract

A Raman Lidar (RL) system is developed to measure the water vapor mixing ratio (WVMR) and aerosol optical property in Wuhan with high temporal-spatial resolution during rainless nights. The principle of the self-developed lidar system and data processing method are discussed. WVMR profiles [...] Read more.

A Raman Lidar (RL) system is developed to measure the water vapor mixing ratio (WVMR) and aerosol optical property in Wuhan with high temporal-spatial resolution during rainless nights. The principle of the self-developed lidar system and data processing method are discussed. WVMR profiles of a representative case retrieved by RL, Radiosonde (RS), and microwave radiometer (MR) are in good agreement. The relationship of WVMR and aerosol optical depth (AOD) indicates that water vapor dramatically reduces with the decline of the AOD. Moreover, the mean relative difference of mean WVMRs at low-troposphere obtained by RL and RS (MR) is about 5.17% (9.47%) during the analyzed year. The agreement certifies that the self-developed RL system can stably provide accurate and high temporal-spatial resolution data for the fundamental physical studies on water vapor. Furthermore, the maximum AOD from 0.5 km to 3 km is 0.41 at night in spring, which indicates that the air quality in Wuhan is heavily influenced by aerosols that are transported by air mass from the north during this time. Moreover, abundant rainfall led to relatively low AOD in summer (0.22), which demonstrates that water vapor is crucial for air purification. Full article

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2687 KiB

Open AccessArticle

An Investigation of Aerosol Scattering and Absorption Properties in Wuhan, Central China

by Wei Gong, Miao Zhang, Ge Han, Xin Ma and Zhongmin Zhu

Atmosphere 2015, 6(4), 503-520; https://doi.org/10.3390/atmos6040503 - 3 Apr 2015

Cited by 35 | Viewed by 6927

Abstract

Aerosol scattering and absorption properties were continuously measured and analyzed at the urban Laboratory for Information Engineering in Surveying, Mapping and Remote Sensing (LIESMARS) site in Wuhan, central China, from 1 December 2009 to 31 March 2014. The mean aerosol scattering coefficient , [...] Read more.

Aerosol scattering and absorption properties were continuously measured and analyzed at the urban Laboratory for Information Engineering in Surveying, Mapping and Remote Sensing (LIESMARS) site in Wuhan, central China, from 1 December 2009 to 31 March 2014. The mean aerosol scattering coefficient , absorption coefficient , and single scattering albedo (SSA) were 377.54 Mm⁻¹, 119.06 Mm⁻¹, and 0.73, respectively. Both and showed obvious annual variability with large values in winter and small values in summer, principally caused by the annual characteristics of meteorological conditions, especially planetary boundary layer height (PBLH) and local emissions. The SSA showed a slight annual variation. High values of SSA were related to formation of secondary aerosols in winter hazes and aerosol hygroscopic growth in humid summer. The large SSA in June can be attributed to the biomass combustion in Hubei and surrounding provinces. Both and showed double peak phenomena in diurnal variation resulting from the shallow stable PBLH at night and automobile exhaust emission during morning rush hours. The SSA also exhibited a double peak phenomenon related to the proportional variation of black carbon (BC) and light scattering particulates in the day and night. The long-term exploration on quantified aerosol optical properties can help offer scientific basis of introducing timely environmental policies for local government. Full article

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1520 KiB

Open AccessArticle

An Investigation of Atmospheric Mercury from Power Sector in Thailand

by Thao Thi Bich Pham, Agapol Junpen and Savitri Garivait

Atmosphere 2015, 6(4), 490-502; https://doi.org/10.3390/atmos6040490 - 3 Apr 2015

Cited by 6 | Viewed by 6347

Abstract

Mercury (Hg) is a highly toxic pollutant with a long range transport in the atmosphere resulting in both local and global concerns. Understanding of emissions is required to support an effective control strategy. In this study, atmospheric Hg emissions from power sector in [...] Read more.

Mercury (Hg) is a highly toxic pollutant with a long range transport in the atmosphere resulting in both local and global concerns. Understanding of emissions is required to support an effective control strategy. In this study, atmospheric Hg emissions from power sector in Thailand in 2010 were investigated by using the bottom-up approach to improve the accuracy of the estimate by up to 50% in comparison to those provided in global inventories. The activity data of each individual source were collected and emissions factors were assessed based on local sources, well reflecting the emissions behavior of various emitters in Thailand. The atmospheric Hg emissions from power sector in 2010 amounted to 844.5 kg, in which emissions from coal and lignite power plants constituted up to 92.3% and biomass power plants constituted up to 7.4%. Spatial and temporal distribution analysis indicated high emissions in the Central and Northern regions, and from February to July. Annual trends in emissions from 2010 to 2030 were estimated and discussed. Full article

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857 KiB

Open AccessArticle

Evaluation of Policy Influence on Long-Term Indoor Air Quality in Emperor Qin’s Terra-Cotta Museum, China

by Hua Li, Tafeng Hu, Wenting Jia, Junji Cao, Suixin Liu, Rujin Huang, Tao Ma and Na Xi

Atmosphere 2015, 6(4), 474-489; https://doi.org/10.3390/atmos6040474 - 3 Apr 2015

Cited by 4 | Viewed by 5833

Abstract

Long-term measurement results of indoor air quality (IAQ) from 1989 to 2013 inside Pit No. 1, the largest display hall in Emperor Qin’s Terra-cotta Museum (QTM), were used to evaluate the effectiveness of measures for conservation environment improvement of antiques. By comparing the [...] Read more.

Long-term measurement results of indoor air quality (IAQ) from 1989 to 2013 inside Pit No. 1, the largest display hall in Emperor Qin’s Terra-cotta Museum (QTM), were used to evaluate the effectiveness of measures for conservation environment improvement of antiques. By comparing the results of sampling campaigns in 2013 with databases in 1989, 2004–2005, 2006–2007 and 2011, seasonal and inter-annual variation in microclimate, aerosol chemical compositions and gaseous pollutant concentrations were incorporated in estimating the probable influences of the management of the surroundings, tourist flow, excavation and restoration tasks and renovation and/or new construction work on IAQ in the QTM. After the implementation of the environmental policies in 1990s, a significant decrease of indoor particulate matter mass for the QTM was quantified. The mass concentrations of summer TSP decreased from 540.0 μg∙m⁻³ in 1994 to 172.4 μg∙m⁻³ in 2004, as well as the winter TSP decreased from 380.0 μg∙m⁻³ in 1994 to 312.5 μg∙m⁻³ in 2005. The mass concentrations of summer PM_2.5 decreased from 108.4 μg∙m⁻³ in 2004 to 65.7 μg∙m⁻³ in 2013, as well as the winter PM_2.5 decreased from 242.3 μg∙m⁻³ in 2005 to 98.6 μg∙m⁻³ in 2013. However, it is noted that potential hazards due to the fluctuant microclimate conditions, gaseous and secondary particulate acidic species in indoor air should still be considered to ensure the long-term preservation and conservation of the museum’s artifact collection. Full article

(This article belongs to the Special Issue Sources, Formation and Impacts of Secondary Aerosol)

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2263 KiB

Open AccessArticle

Precipitation Sensitivity to the Mean Radius of Drop Spectra: Comparison of Single- and Double-Moment Bulk Microphysical Schemes

by Nemanja Kovačević and Mladjen Ćurić

Atmosphere 2015, 6(4), 451-473; https://doi.org/10.3390/atmos6040451 - 1 Apr 2015

Cited by 4 | Viewed by 4717

Abstract

In this study, two bulk microphysical schemes were compared across mean radius values of the entire drop spectra. A cloud-resolving mesoscale model was used to analyze surface precipitation characteristics. The model included the following microphysical categories: water vapour, cloud droplets, raindrops, ice crystals, [...] Read more.

In this study, two bulk microphysical schemes were compared across mean radius values of the entire drop spectra. A cloud-resolving mesoscale model was used to analyze surface precipitation characteristics. The model included the following microphysical categories: water vapour, cloud droplets, raindrops, ice crystals, snow, graupel, frozen raindrops and hail. Two bulk schemes were used: a single-moment scheme in which the mean radius was specified as a parameter and a double-moment scheme in which the mean radius of drops was calculated diagnostically with a fixed value for the cloud droplet number concentration. Experiments were conducted out for three values of the mean radius (in the single-moment scheme) and two cloud droplet number concentrations (in the double-moment scheme). There were large differences in the surface precipitation for the two schemes, the simulated precipitation generated by the double-moment scheme had a higher sensitivity. The single-moment scheme generated an unrealistic collection rate of cloud droplets by raindrops and hail as well as unrealistic evaporation of rain and melting of solid hydrometeors; these processes led to inaccurate timing and amounts of surface precipitation. Full article

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1920 KiB

Open AccessArticle

Probabilistic Analysis of Drought Spatiotemporal Characteristics in the Beijing-Tianjin-Hebei Metropolitan Area in China

by Wanyuan Cai, Yuhu Zhang, Yunjun Yao and Qiuhua Chen

Atmosphere 2015, 6(4), 431-450; https://doi.org/10.3390/atmos6040431 - 27 Mar 2015

Cited by 14 | Viewed by 6517

Abstract

The temporal and spatial characteristics of meteorological drought have been investigated to provide a framework of methodologies for the analysis of drought in the Beijing-Tianjin-Hebei metropolitan area (BTHMA) in China. Using the Reconnaissance Drought Index (RDI) as an indicator of drought severity, the [...] Read more.

The temporal and spatial characteristics of meteorological drought have been investigated to provide a framework of methodologies for the analysis of drought in the Beijing-Tianjin-Hebei metropolitan area (BTHMA) in China. Using the Reconnaissance Drought Index (RDI) as an indicator of drought severity, the characteristics of droughts have been examined. The Beijing-Tianjin-Hebei metropolitan area was divided into 253 grid-cells of 27 × 27km and monthly precipitation data for the period of 1960–2010 from 33 meteorological stations were used for global interpolation of precipitation using spatial co-ordinate data. Drought severity was assessed from the estimated gridded RDI values at multiple time scales. Firstly, the temporal and spatial characteristics of droughts were analyzed, and then drought severity-areal extent-frequency (SAF) annual curves were developed. The analysis indicated that the frequency of moderate and severe droughts was about 9.10% in the BTHMA. Using the SAF curves, the return period of selected severe drought events was assessed. The identification of the temporal and spatial characteristics of droughts in the BTHMA will be useful for the development of a drought preparedness plan in the region. Full article

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2272 KiB

Open AccessArticle

Drought Forecasting Using Stochastic Models in a Hyper-Arid Climate

by Amr Mossad and Abdulrahman Ali Alazba

Atmosphere 2015, 6(4), 410-430; https://doi.org/10.3390/atmos6040410 - 25 Mar 2015

Cited by 41 | Viewed by 7416

Abstract

Drought forecasting plays a crucial role in drought mitigation actions. Thus, this research deals with linear stochastic models (autoregressive integrated moving average (ARIMA)) as a suitable tool to forecast drought. Several ARIMA models are developed for drought forecasting using the Standardized Precipitation Evapotranspiration [...] Read more.

Drought forecasting plays a crucial role in drought mitigation actions. Thus, this research deals with linear stochastic models (autoregressive integrated moving average (ARIMA)) as a suitable tool to forecast drought. Several ARIMA models are developed for drought forecasting using the Standardized Precipitation Evapotranspiration Index (SPEI) in a hyper-arid climate. The results reveal that all developed ARIMA models demonstrate the potential ability to forecast drought over different time scales. In these models, the p, d, q, P, D and Q values are quite similar for the same SPEI time scale. This is in correspondence with autoregressive (AR) and moving average (MA) parameter estimate values, which are also similar. Therefore, the ARIMA model (1, 1, 0) (2, 0, 1) could be considered as a general model for the Al Qassim region. Meanwhile, the ARIMA model (1, 0, 3) (0, 0, 0) at 3-SPEI and the ARIMA model (1, 1, 1) (2, 0, 1) at 24-SPEI could be generalized for the Hail region. The ARIMA models at the 24-SPEI time scale is the best forecasting models with high R² (more than 0.9) and lower values of RMSE and MAE, while they are the least forecasting at the 3-SPEI time scale. Accordingly, this study recommends that ARIMA models can be very useful tools for drought forecasting that can help water resource managers and planners to take precautions considering the severity of drought in advance. Full article

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Atmosphere, Volume 6, Issue 4 (April 2015) – 8 articles , Pages 410-546

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