scholarly journals Surprising observation of large anthropogenic aerosol fraction over the “near-pristine” southern Bay of Bengal: Climate implications

2010 ◽  
Vol 115 (D21) ◽  
Author(s):  
Vijayakumar S. Nair ◽  
S. K. Satheesh ◽  
K. Krishna Moorthy ◽  
S. Suresh Babu ◽  
Prabha R. Nair ◽  
...  
Keyword(s):  
Bay Of Bengal ◽  
Anthropogenic Aerosol ◽  
Aerosol Fraction ◽  
Surprising Observation

scholarly journals Potential of polarization/Raman lidar to separate fine dust, coarse dust, maritime, and anthropogenic aerosol profiles

2017 ◽  
Author(s):  
Rodanthi-Elisavet Mamouri ◽  
Albert Ansmann
Keyword(s):  
Raman Lidar ◽  
Anthropogenic Aerosol ◽  
Conversion Factors ◽  
Extended Approach ◽  
Lidar Measurements ◽  
Range Transport ◽  
Aerosol Fraction ◽  
Interaction Experiment ◽  
New Feature ◽  
Lidar Observations

Abstract. We applied the recently introduced Polarization Lidar Photometer Networking (POLIPHON) technique for the first time to triple-wavelength polarization lidar measurements at 355, 532, and 1064 nm. The lidar observations were performed at Barbados during the Saharan Aerosol Long-Range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) in the summer of 2014. POLIPHON comprises the traditional lidar technique to separate mineral dust and non-dust backscatter contributions and the new extended approach to separate even the dust backscatter component into fine and coarse dust fractions. We show that the traditional and the extended methods are compatible and lead to the same set of dust and non-dust profiles at simplified, less complex aerosol layering and mixing conditions as is the case over the remote tropical Atlantic. To derive dust mass concentration profiles from the lidar observations, trustworthy extinction-to-volume conversion factors are needed and obtained from an updated, extended AERONET sun photometer data analysis of the correlation of fine, coarse and total dust volume concentration with dust extinction coefficients for all three laser wavelengths. Conversion factors for pure marine aerosol conditions and continental anthropogenic aerosol situations are presented in addition. As an additional new feature of POLIPHON, the Raman-lidar method for particle extinction profiling is used to identify the aerosol type (marine or anthropogenic) of the non-dust aerosol fraction. The full POLIPHON methodology was successfully applied to a SALTRACE case and the results are discussed. We conclude that the 532 nm polarization lidar technique has many advantages in comparison to respective 355 and 1064 nm polarization lidar approaches and leads to most robust and accurate POLIPHON products.

scholarly journals Extremely large anthropogenic aerosol component over the Bay of Bengal during winter season

2011 ◽  
Vol 11 (3) ◽  
pp. 7851-7907 ◽  
Author(s):  
D. G. Kaskaoutis ◽  
S. Kumar Kharol ◽  
P. R. Sinha ◽  
R. P. Singh ◽  
H. D. Kambezidis ◽  
...  
Keyword(s):  
Bay Of Bengal ◽  
Winter Season ◽  
Anthropogenic Pollution ◽  
Anthropogenic Emissions ◽  
Anthropogenic Aerosol ◽  
Temporal And Spatial Variability ◽  
Size Growth ◽  
Fine Mode ◽  
First Time ◽  
The Relationship

Abstract. Ship-borne observations of spectral aerosol optical depth (AOD) have been carried out over the entire Bay of Bengal (BoB) as part of the W-ICARB cruise campaign during the period 27 December 2008–30 January 2009. The results reveal a pronounced temporal and spatial variability in the optical characteristics of aerosols mainly due to anthropogenic emissions and their dispersion controlled by local meteorology. The highest aerosol amount, with mean AOD500 over 0.4, being even above 1.0 on specific days, is found close to the coastal regions in the western and northern parts of BoB. In these regions the Ångström exponent is also found to be high (~ 1.2–1.25) indicating transport of strong anthropogenic emissions from continental regions. A very high AOD500 (0.39 ± 0.07) and α380—870 values (1.27 ± 0.09) are found for the first time over the Eastern BoB, which was unexplored in the earlier ICARB-06 campaign. Except from the large α380—870 values, an indication of strong fine-mode dominance is also observed from the AOD curvature, which is negative in the vast majority of the cases, suggesting dominance of an anthropogenic-pollution aerosol type. On the other hand, clean maritime conditions are rather rare over the region, while the aerosol types are further examined through a classification scheme using the relationship between α and dα. It was found that even for the same α values the fine-mode dominance is larger for higher AODs showing the strong continental influence over the marine environment of BoB. Furthermore, there is also an evidence of aerosol size growth under more turbid conditions indicative of coagulation and/or humidification over specific BoB regions. The results obtained using OPAC model show significant fraction of soot aerosols (~ 6–8%) over the Eastern and Northwestern BoB, while coarse-mode sea salt particles are found to dominate in the southern parts of BoB.

Anthropogenic aerosol fraction over Afro-Asian regions inferred using Kalpana-I and MISR data

2011 ◽  
Vol 2 (1) ◽  
pp. 1-9 ◽  
Author(s):  
N. Srivastava ◽  
S. K. Satheesh ◽  
C. B. S. Dutt ◽  
K. S. Jagannath
Keyword(s):  
Anthropogenic Aerosol ◽  
Aerosol Fraction

scholarly journals Potential of polarization/Raman lidar to separate fine dust, coarse dust, maritime, and anthropogenic aerosol profiles

2017 ◽  
Vol 10 (9) ◽  
pp. 3403-3427 ◽  
Author(s):  
Rodanthi-Elisavet Mamouri ◽  
Albert Ansmann
Keyword(s):  
Data Analysis ◽  
Raman Lidar ◽  
Anthropogenic Aerosol ◽  
Conversion Factors ◽  
Total Dust ◽  
Lidar Measurements ◽  
Range Transport ◽  
Aerosol Fraction ◽  
New Feature ◽  
Lidar Observations

Abstract. We applied the recently introduced polarization lidar–photometer networking (POLIPHON) technique for the first time to triple-wavelength polarization lidar measurements at 355, 532, and 1064 nm. The lidar observations were performed at Barbados during the Saharan Aerosol Long-Range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) in the summer of 2014. The POLIPHON method comprises the traditional lidar technique to separate mineral dust and non-dust backscatter contributions and the new, extended approach to separate even the fine and coarse dust backscatter fractions. We show that the traditional and the advanced method are compatible and lead to a consistent set of dust and non-dust profiles at simplified, less complex aerosol layering and mixing conditions as is the case over the remote tropical Atlantic. To derive dust mass concentration profiles from the lidar observations, trustworthy extinction-to-volume conversion factors for fine, coarse, and total dust are needed and obtained from an updated, extended Aerosol Robotic Network sun photometer data analysis of the correlation between the fine, coarse and total dust volume concentration and the respective fine, coarse, and total dust extinction coefficient for all three laser wavelengths. Conversion factors (total volume to extinction) for pure marine aerosol conditions and continental anthropogenic aerosol situations are presented in addition. As a new feature of the POLIPHON data analysis, the Raman lidar method for particle extinction profiling is used to identify the aerosol type (marine or anthropogenic) of the non-dust aerosol fraction. The full POLIPHON methodology was successfully applied to a SALTRACE case and the results are discussed. We conclude that the 532 nm polarization lidar technique has many advantages in comparison to 355 and 1064 nm polarization lidar approaches and leads to the most robust and accurate POLIPHON products.

scholarly journals Extremely large anthropogenic-aerosol contribution to total aerosol load over the Bay of Bengal during winter season

2011 ◽  
Vol 11 (14) ◽  
pp. 7097-7117 ◽  
Author(s):  
D. G. Kaskaoutis ◽  
S. Kumar Kharol ◽  
P. R. Sinha ◽  
R. P. Singh ◽  
H. D. Kambezidis ◽  
...  
Keyword(s):  
Bay Of Bengal ◽  
Winter Season ◽  
Anthropogenic Pollution ◽  
Anthropogenic Emissions ◽  
Anthropogenic Aerosol ◽  
Temporal And Spatial Variability ◽  
Size Growth ◽  
Fine Mode ◽  
The Relationship ◽  
Aerosol Type

Abstract. Ship-borne observations of spectral aerosol optical depth (AOD) have been carried out over the entire Bay of Bengal (BoB) as part of the W-ICARB cruise campaign during the period 27 December 2008–30 January 2009. The results reveal a pronounced temporal and spatial variability in the optical characteristics of aerosols mainly due to anthropogenic emissions and their dispersion controlled by local meteorology. The highest aerosol amount, with mean AOD500>0.4, being even above 1.0 on specific days, is found close to the coastal regions in the western and northern parts of BoB. In these regions the Ångström exponent is also found to be high (~1.2–1.25) indicating transport of strong anthropogenic emissions from continental regions, while very high AOD500 (0.39±0.07) and α380–870 values (1.27±0.09) are found over the eastern BoB. Except from the large α380–870 values, an indication of strong fine-mode dominance is also observed from the AOD curvature, which is negative in the vast majority of the cases, suggesting dominance of an anthropogenic-pollution aerosol type. On the other hand, clean maritime conditions are rather rare over the region, while the aerosol types are further examined through a classification scheme based on the relationship between α and dα. It was found that even for the same α values the fine-mode dominance is larger for higher AODs showing the strong continental influence over the marine environment of BoB. Furthermore, there is also an evidence of aerosol-size growth under more turbid conditions indicative of coagulation and/or humidification over specific BoB regions. The results obtained using OPAC model show significant fraction of soot aerosols (~6 %–8 %) over the eastern and northwestern BoB, while coarse-mode sea salt particles are found to dominate in the southern parts of BoB.

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