scholarly journals Columnar aerosol types and compositions over peninsular Southeast Asia based on long-term AERONET data

2021 ◽  
Author(s):  
Sheng-Hsiang Wang ◽  
Hsiang-Yu Huang ◽  
Che-Hsuan Lin ◽  
Shantanu Kumar Pani ◽  
Neng-Huei Lin ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Radiative Forcing ◽  
Dust Particles ◽  
Chemical Components ◽  
Carbonaceous Aerosols ◽  
Land Use Pattern ◽  
Aerosol Aging ◽  
Aerosol Types ◽  
Aerosol Type

AbstractAerosol chemical components such as black carbon (BC) and brown carbon (BrC) regulate aerosol optical properties, which in turn drive the atmospheric radiative forcing estimations due to aerosols. In this study, we used the long-term measurements from AERONET (Aerosol Robotic Network) to better understand the aerosol types and composition with respect to their seasonal and spatial variabilities in peninsular Southeast Asia (PSEA, here defined as Vietnam, Cambodia, Thailand, Laos, and Myanmar). Two methods (i.e., aerosol type cluster and aerosol component retrieval) were applied to determine the aerosol type and chemical composition during the biomass-burning (BB) season. AERONET sites in northern PSEA showed a higher AOD (aerosol optical depth) compared to that of southern PSEA. Differences in land use pattern, geographic location, and weather regime caused much of the aerosol variability over PSEA. Lower single-scattering albedo (SSA) and higher fine-mode fraction (FMF) values were observed in February and March, suggesting the predominance of BB type aerosols with finer and stronger absorbing particles during the dry season. However, we also found that the peak BB month (i.e., March) in northern PSEA may not coincide with the lowest SSA once dust particles have mixed with the other aerosols. Furthermore, we investigated two severe BB events in March of 2014 and 2015, revealing a significant BrC fraction during BB event days. On high AOD days, although the BC fraction was high, the BrC fraction remained low due to lack of aerosol aging. This study highlights the dominance of carbonaceous aerosols in the PSEA atmosphere during the BB season, while also revealing that transported dust particles and BrC aerosol aging may introduce uncertainties into the aerosol radiative forcing calculation.

scholarly journals Aerosol-type classification based on AERONET version 3 inversion products

2019 ◽  
Vol 12 (7) ◽  
pp. 3789-3803 ◽  
Author(s):  
Sung-Kyun Shin ◽  
Matthias Tesche ◽  
Youngmin Noh ◽  
Detlef Müller
Keyword(s):  
East Asia ◽  
Biomass Burning ◽  
Mineral Dust ◽  
Anthropogenic Pollution ◽  
Single Scattering ◽  
Asian Dust ◽  
Dust Particles ◽  
Aerosol Types ◽  
Type Classification ◽  
Aerosol Type

Abstract. This study proposes an aerosol-type classification based on the particle linear depolarization ratio (PLDR) and single-scattering albedo (SSA) provided in the AErosol RObotic NETwork (AERONET) version 3 level 2.0 inversion product. We compare our aerosol-type classification with an earlier method that uses fine-mode fraction (FMF) and SSA. Our new method allows for a refined classification of mineral dust that occurs as a mixture with other absorbing aerosols: pure dust (PD), dust-dominated mixed plume (DDM), and pollutant-dominated mixed plume (PDM). We test the aerosol classification at AERONET sites in East Asia that are frequently affected by mixtures of Asian dust and biomass-burning smoke or anthropogenic pollution. We find that East Asia is strongly affected by pollution particles with high occurrence frequencies of 50 % to 67 %. The distribution and types of pollution particles vary with location and season. The frequency of PD and dusty aerosol mixture (DDM+PDM) is slightly lower (34 % to 49 %) than pollution-dominated mixtures. Pure dust particles have been detected in only 1 % of observations. This suggests that East Asian dust plumes generally exist in a mixture with pollution aerosols rather than in pure form. In this study, we have also considered data from selected AERONET sites that are representative of anthropogenic pollution, biomass-burning smoke, and mineral dust. We find that average aerosol properties obtained for aerosol types in our PLDR–SSA-based classification agree reasonably well with those obtained at AERONET sites representative for different aerosol types.

scholarly journals Haze Optical Properties from Long-Term Ground-Based Remote Sensing over Beijing and Xuzhou, China

2018 ◽  
Vol 10 (4) ◽  
pp. 518 ◽  
Author(s):  
Kai Qin ◽  
Luyao Wang ◽  
Jian Xu ◽  
Husi Letu ◽  
Kefei Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Radiative Forcing ◽  
Fine Particles ◽  
Global Climate ◽  
Complex Refractive Index ◽  
Eastern China ◽  
Single Scattering ◽  
Dust Particles ◽  
Haze Pollution

Aerosol haze pollution has had a significant impact on both global climate and the regional air quality of Eastern China, which has a high proportion of high level pollution days. Statistical analyses of aerosol optical properties and direct radiative forcing at two AERONET sites (Beijing and Xuzhou) were conducted from 2013 to 2016. Results indicate: (1) Haze pollution days accounted for 26% and 20% of days from 2013 to 2016 in Beijing and Xuzhou, respectively, with the highest proportions in winter; (2) The averaged aerosol optical depth (AOD) at 550 nm on haze days were about 3.7 and 1.6 times greater than those on clean days in Beijing and Xuzhou, respectively. At both sites, the maximum AOD occurred in summer; (3) Hazes were dominated by fine particles at both sites. However, as compared to Xuzhou, Beijing had larger coarse mode AOD and higher percentage of small α. This data, together with an analysis of size distribution, suggests that the hazes in Beijing were more susceptible to coarse dust particles than Xuzhou; (4) During hazes in Beijing, the single scattering albedo (SSA) is significantly higher when compared to clean conditions (0.874 vs. 0.843 in SSA440 nm), an increase much less evident in Xuzhou. The most noticeable differences in both SSA and the imaginary part of the complex refractive index between Beijing and Xuzhou were found in winter; (5) In Beijing, the haze radiative forcing produced an averaged cooling effect of −113.6 ± 63.7 W/m2 at the surface, whereas the averaged heating effect of 77.5 ± 49.7 W/m2 within the atmosphere was at least twice as strong as clean days. In Xuzhou, such a radiative forcing effect appeared to be much smaller and the difference between haze and clean days was insignificant. Derived from long-term observation, these findings are more significant for the improvement of our understanding of haze formation in China and the assessment of its impacts on radiative forcing of climate change than previous short-term case studies.

scholarly journals Aerosol-type classification based on AERONET version 3 inversion products

2019 ◽  
Author(s):  
Sung-Kyun Shin ◽  
Matthias Tesche ◽  
Youngmin Noh ◽  
Detlef Müller
Keyword(s):  
East Asia ◽  
Biomass Burning ◽  
Mineral Dust ◽  
Anthropogenic Pollution ◽  
Single Scattering ◽  
Asian Dust ◽  
Dust Particles ◽  
Aerosol Types ◽  
Type Classification ◽  
Aerosol Type

Abstract. This study proposes an aerosol-type classification based on the particle linear depolarization ratio (PLDR) and single scattering albedo (SSA) provided in the AErosol RObotic NETwork (AERONET) version 3 level 2.0 inversion product. We compare our aerosol-type classification with an earlier method that uses fine-mode fraction (FMF) and SSA. Our new method allows for a refined classification of mineral dust that occurs as a mixture with other absorbing aerosols: pure dust (PD), dust-dominated mixed plume (DDM), and pollutant-dominated mixed plume (PDM). We test the aerosol classification at AERONET sites in East Asia that are frequently affected by mixtures of Asian dust and biomass-burning smoke or anthropogenic pollution. We find that East Asia is strongly affected by pollution particles with high occurrence frequencies of 50 % to 67 %. The distribution and types of pollution particles vary with location and season. The frequency of PD and dusty aerosol mixture (DDM+PDM) is slightly lower (34 % to 49 %) than pollution-dominated mixtures. Pure dust particles have been detected in only 1 % of observations. This suggests that East Asian dust plumes generally exist in a mixture with pollution aerosols rather than in pure form. In this study, we have also considered data from selected AERONET sites that are representative of anthropogenic pollution, biomass-burning smoke, and mineral dust. We find that average aerosol properties obtained for aerosol types in our PLDR-SSA-based classification agree reasonably well with those obtained at AERONET sites representative for different aerosol types.

scholarly journals Modulation of Saharan dust export by the North African dipole

2014 ◽  
Vol 14 (19) ◽  
pp. 26689-26719 ◽  
Author(s):  
S. Rodríguez ◽  
E. Cuevas ◽  
J. M. Prospero ◽  
A. Alastuey ◽  
X. Querol ◽  
...  
Keyword(s):  
North Africa ◽  
North Atlantic ◽  
Radiative Forcing ◽  
Saharan Dust ◽  
Dust Particles ◽  
North African ◽  
Inter Tropical Convergence Zone ◽  
The North ◽  
The Tropics

Abstract. Desert dust aerosols influence air quality and climate on a global scale, including radiative forcing, cloud properties and carbon dioxide modulation through ocean fertilisation. North Africa is the largest and most active dust source worldwide; however, the mechanisms modulating year-to-year variability in Saharan dust export in summer remains unclear. In this season, enhanced dust mobilization in the hyper-arid Sahara results in maximum dust impacts throughout the North Atlantic. The objective of this study is to identify the relationship between the long term interannual variability in Saharan dust export in summer and large scale meteorology in western North Africa. We address this issue by analysing ~25 yr (1987–2012) dust concentrations at the high altitude Izaña observatory (2373 m a.s.l.) in Tenerife Island, satellite and meteorological reanalysis data. Because in summer Saharan dust export occurs at altitudes 1–5 km, we paid special attention to the summer meteorological scenario in the 700 hPa standard level, characterised by a high over the subtropical Sahara and lower geopotential heights over the tropics; we measured the intensity of this low-high dipole like pattern in terms of the North AFrican Dipole Index (NAFDI): the difference of the 700 hPa geopotential heights anomalies averaged over central Morocco (subtropic) and over Bamako region (tropic). The correlations we found between the 1987–2012 NAFDI with dust at Izaña, satellite dust observations and meteorological re-analysis data, indicates that increase in the NAFDI (i) results in higher wind speeds at the north of the Inter-Tropical Convergence Zone which enhances dust export over the subtropical North Atlantic, (ii) influences on the size distribution of exported dust particles, increasing the load of coarse dust and (iii) are associated with higher rainfall over tropical North Africa and the Sahel. Because of the North African dipole modulation, inter-annual variability in Saharan dust export is correlated with monsoon rainfall in the Sahel. High values of the NAFDI enhance dust export at subtropical latitudes. Our results suggest that long term variability in Saharan dust export may be influenced by global oscillations in the climate of the tropics and subtropics and that this may have influenced dust transport pathways in the last decades.

REPEATED LONG-TERM SPACE FLIGHTS: PROTEOMIC INVESTIGATIONS OF COSMONAUTS' BLOOD

2020 ◽  
Vol 54 (5) ◽  
pp. 15-22
Author(s):  
I.M. Larina ◽  
◽  
D.N. Kashirina ◽  
K.S. Kireev ◽  
A.I. Grigoriev ◽  
...  
Keyword(s):  
Bone Structure ◽  
Space Station ◽  
The Body ◽  
Coagulation Cascade ◽  
Chemical Components ◽  
Blood Proteins ◽  
Blood Indices ◽  
Before And After ◽  
Biochemical Indices

We performed the first ever comparative analysis of modifications in the proteome, ionogram and some other blood plasma biochemical indices of 18 male cosmonauts (44 ± 6 years of age) before and after maiden or repeated long-term missions to the Russian segment of the International space station (ISS RS). Levels of proteins, substrates and ions as well as chemical components were measured using the LC-MS-based proteomics and routine biochemical techniques. A total of 256 to 281 indices were investigated with the methods of descriptive statistic, regression analysis, and access to bioinformatics resources. It was shown that blood indices recovery from the maiden and repeated missions reflects changes in the body systems and goes at a various speed. The results of measurements made prior to launch and on day 7 after landing are dependent on the number of missions. The bioinformatics techniques showed that after maiden missions both the mediator proteins of alkaline phosphatase (AP) and blood proteins with reliably changing concentrations are associated with the bio-processes including stress, metabolism and DNA reparation, apoptosis, catabolism and proteolysis. During early re-adaptation from repeated missions the AP level was affected by bone remodeling, phosphorylation, angiogenesis and coagulation cascade suggesting a distinct and urgent trigger of the processes of bone structure and mineralization.

scholarly journals Aerosol optical depth retrievals at the Izaña Atmospheric Observatory from 1941 to 2013 by using artificial neural networks

2016 ◽  
Vol 9 (1) ◽  
pp. 53-62 ◽  
Author(s):  
R. D. García ◽  
O. E. García ◽  
E. Cuevas ◽  
V. E. Cachorro ◽  
A. Barreto ◽  
...  
Keyword(s):  
Neural Networks ◽  
Time Series ◽  
Artificial Neural Networks ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Mineral Dust ◽  
Dust Particles ◽  
Filter Radiometer ◽  
Artificial Neural

Abstract. This paper presents the reconstruction of a 73-year time series of the aerosol optical depth (AOD) at 500 nm at the subtropical high-mountain Izaña Atmospheric Observatory (IZO) located in Tenerife (Canary Islands, Spain). For this purpose, we have combined AOD estimates from artificial neural networks (ANNs) from 1941 to 2001 and AOD measurements directly obtained with a Precision Filter Radiometer (PFR) between 2003 and 2013. The analysis is limited to summer months (July–August–September), when the largest aerosol load is observed at IZO (Saharan mineral dust particles). The ANN AOD time series has been comprehensively validated against coincident AOD measurements performed with a solar spectrometer Mark-I (1984–2009) and AERONET (AErosol RObotic NETwork) CIMEL photometers (2004–2009) at IZO, obtaining a rather good agreement on a daily basis: Pearson coefficient, R, of 0.97 between AERONET and ANN AOD, and 0.93 between Mark-I and ANN AOD estimates. In addition, we have analysed the long-term consistency between ANN AOD time series and long-term meteorological records identifying Saharan mineral dust events at IZO (synoptical observations and local wind records). Both analyses provide consistent results, with correlations  >  85 %. Therefore, we can conclude that the reconstructed AOD time series captures well the AOD variations and dust-laden Saharan air mass outbreaks on short-term and long-term timescales and, thus, it is suitable to be used in climate analysis.

scholarly journals Evaluations of Surface PM10 Concentration and Chemical Compositions in MERRA-2 Aerosol Reanalysis over Central and Eastern China

2021 ◽  
Vol 13 (7) ◽  
pp. 1317
Author(s):  
Xiaodan Ma ◽  
Peng Yan ◽  
Tianliang Zhao ◽  
Xiaofang Jia ◽  
Jian Jiao ◽  
...  
Keyword(s):  
Eastern China ◽  
Mainland China ◽  
Chemical Components ◽  
Chemical Compositions ◽  
Observation Data ◽  
Causative Factors ◽  
Routine Sampling ◽  
Aerosol Compositions ◽  
Modern Era

The chemical composition dataset of Aerosol Reanalysis of NASA’s Modern-Era Retrospective Analysis for Research and Application, version 2 (MERRAero) has not been thoroughly evaluated with observation data in mainland China due to the lack of long-term chemical components data. Using the 5-year data of PM10 mass concentrations and chemical compositions obtained from the routine sampling measurements at the World Meteorological Organization the Global Atmosphere Watch Programme regional background stations, Jing Sha (JS) and Lin’An (LA), in central and eastern China, we comprehensively evaluate the surface PM10 concentrations and chemical compositions such as sulfate (SO42−), organic carbon (OC) and black carbon (BC) derived from MERRAero. Overall, the concentrations of PM10, SO42−, OC and BC from the MERRAero agreed well with the measurements, despite a slight and consistent overestimation of BC concentrations and a moderate and persistent underestimation of PM10 concentrations throughout the study period. The MERRAero reanalysis of aerosol compositions performs better during the summertime than wintertime. By considering the nitrate particles in PM10 reconstruction, MERRAero performance can be significantly improved. The unreasonable seasonal variations of PM10 chemical compositions at station LA by MERRAero could be causative factors for the larger MERRAero discrepancies during 2016–2017 than the period of 2011–2013.

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