LED-DOAS Instrument for Monitoring Aerosol Optical Properties in the Planetary Boundary Layer

2021 ◽  
pp. 75-85
Author(s):  
Jamrud Aminuddin
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Planetary Boundary Layer ◽  
Aerosol Optical Properties

scholarly journals Seasonal variability of aerosol optical properties observed by means of a Raman lidar at an EARLINET site over Northeastern Spain

2011 ◽  
Vol 11 (1) ◽  
pp. 175-190 ◽  
Author(s):  
M. Sicard ◽  
F. Rocadenbosch ◽  
M. N. M. Reba ◽  
A. Comerón ◽  
S. Tomás ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Planetary Boundary Layer ◽  
Optical Thickness ◽  
Seasonal Variability ◽  
Aerosol Optical Thickness ◽  
Saharan Dust ◽  
Raman Lidar ◽  
Aerosol Optical Properties ◽  
Lidar Ratio

Abstract. The annual and seasonal variability of aerosol optical properties observed by means of a Raman lidar over Northeastern Spain has been assessed. The lidar representativeness has first been checked against sun-photometer measurements in terms of aerosol optical thickness. Then the annual cycle and the seasonal variability of the planetary boundary layer aerosol optical thickness and its fraction compared to the columnar optical thickness, the lidar ratio, the backscatter-related Ångström exponent and the planetary boundary layer height are analyzed and discussed. Winter and summer mean profiles of extinction, backscatter and lidar ratio retrieved with the Raman algorithm are presented. The analysis shows the impact of most of the natural events (Saharan dust intrusions, wildfires, etc.) and meteorological situations (summer anticyclonic situation, the formation of the Iberian thermal low, winter long-range transport from North Europe and/or North America, re-circulation flows, etc.) occurring in the Barcelona area. A detailed study of a special event including a combined intrusion of Saharan dust and biomass-burning particles proves the suitability of combining the retrieval of aerosol optical properties from Raman and pure elastic lidar measurements to discriminate spatially different types of aerosols and to follow their spatial and temporal evolution.

scholarly journals Seasonal variability of aerosol optical properties observed by means of an elastic-Raman lidar over Northeastern Spain

2010 ◽  
Vol 10 (6) ◽  
pp. 14053-14094
Author(s):  
M. Sicard ◽  
M. N. M. Reba ◽  
F. Rocadenbosch ◽  
A. Comerón ◽  
S. Tomás ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Planetary Boundary Layer ◽  
Optical Thickness ◽  
Seasonal Variability ◽  
Aerosol Optical Thickness ◽  
Saharan Dust ◽  
Raman Lidar ◽  
Aerosol Optical Properties ◽  
Lidar Ratio

Abstract. The annual and seasonal variability of aerosol optical properties observed by means of an elastic-Raman lidar over Northeastern Spain has been assessed. The lidar representativeness has first been checked against sun-photometer measurements in terms of aerosol optical thickness. Then the annual cycle and the seasonal variability of the planetary boundary layer aerosol optical thickness and its fraction compared to the columnar optical thickness, the lidar ratio, the backscatter-related Ångström exponent and the planetary boundary layer height have been analyzed and discussed. Winter and summer mean profiles of extinction, backscatter and lidar ratio retrieved with the Raman algorithm have been presented. The analysis shows the impact of most of the natural events (Saharan dust intrusions, wildfires, etc.) and meteorological situations (summer anticyclonic situation, the formation of the Iberian thermal low, winter long-range transport from North Europe and/or North America, re-circulation flows, etc.) occurring in the Barcelona area. A detail study of a special event including a combined intrusion of Saharan dust and biomass-burning particles has proven the suitability of combining nighttime Raman- and daytime pure elastic-inversions to discriminate spatially different types of aerosols and to follow their spatial and temporal evolution.

scholarly journals Physical and optical properties of aerosols over an urban location in Spain: seasonal and diurnal variability

2010 ◽  
Vol 10 (1) ◽  
pp. 239-254 ◽  
Author(s):  
H. Lyamani ◽  
F. J. Olmo ◽  
L. Alados-Arboledas
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Seasonal Cycle ◽  
Large Fraction ◽  
Particle Diameter ◽  
Urban Site ◽  
Number Density ◽  
Aerosol Optical Properties ◽  
Scattering Coefficients ◽  
Aerosol Absorption

Abstract. Measurements of aerosol optical properties and aerosol number size distribution obtained during the period from December 2005 to November 2007 at Granada, an urban site in south-eastern Spain, are analyzed. Large variations of the measured variables have been found, and related to variations in emissions sources and meteorological conditions. High values of aerosol absorption and scattering coefficients are obtained during winter and low values are measured during summer. This seasonal pattern in the surface aerosol optical properties is opposite to the seasonal cycle showed by columnar aerosol optical depth. The differences in the seasonal features of the surface and column-integrated data are related to seasonal variations in the aerosol vertical distribution, aerosol sources and boundary layer height. In winter the number density of "fine" particles (0.5<particle diameter<1 μm) is significantly larger than in summer while the number density of "coarse" particles (1<particle diameter<20 μm) is slightly larger during summer and spring than during winter and autumn. The scattering Angström exponent, αs, presents an evident seasonal cycle with values of 1.8±0.2, 1.6±0.3, 1.3±0.3 and 1.4±0.3 in winter, spring, summer and autumn, respectively. This suggests the presence of a large fraction of submicron particles at the site, especially during winter. The aerosols measured in this study contain a large fraction of absorbing material as indicated by the average single-scattering albedo that has values of 0.65±0.07, 0.66±0.06, 0.70±0.06 and 0.73±0.06 in autumn, winter, spring and summer, respectively. The aerosol scattering albedo obtained in the surface boundary layer of Granada is below the critical value of 0.86 that determines the shift from cooling to warming. These results put in evidence the need of efforts to reduce absorbing particles (black carbon) emissions to avoid the possible warming that would result from the reductions of the cooling aerosols only. The aerosol absorption and scattering coefficients present a clear diurnal pattern, in all seasons, with two local maxima, one early in the morning and the second one in the evening. This diurnal cycle is mainly attributed to the diurnal evolution of atmospheric boundary layer and local anthropogenic activities.

scholarly journals Climatological aspects of aerosol optical properties in Northern Greece

2003 ◽  
Vol 3 (2) ◽  
pp. 2059-2099 ◽  
Author(s):  
E. Gerasopoulos ◽  
M. O. Andreae ◽  
C. S. Zerefos ◽  
T. W. Andreae ◽  
D. Balis ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Scattering Coefficient ◽  
Aerosol Optical Properties ◽  
Northern Greece ◽  
Frequency Distributions ◽  
The Mean ◽  
The Impact

Abstract. Measurements of aerosol optical properties (aerosol optical depth, scattering and backscattering coefficients) have been conducted at two ground-based sites in Northern Greece, Ouranoupolis (40° 23' N, 23° 57 E, 170 m a.s.l.) and Thessaloniki (40° 38' N, 22° 57 E, 80 m a.s.l.), between 1999 and 2002. Their frequency distributions have revealed the presence of individual modes of high and low values, indicating the influence from different sources. At both sites, the mean aerosol optical depth at 500 nm was 0.23. Values increase considerably during summer when they remain persistently between 0.3 and 0.5, going up to 0.7–0.8 during specific cases. The mean value of 65±40 Mm−1 of the particle scattering coefficient at 550 nm reflects the impact of continental pollution in the regional boundary layer. Trajectory analysis has shown that higher values of aerosol optical depth and the scattering coefficient are found in the east sector (former Soviet Union countries, eastern Balkan countries), whereas cleaner conditions are found for the NW direction. The influence of Sahara dust events is clearly reflected in the Angström exponents. About 45–60% of the observed diurnal variation of the optical properties was attributed to the growth of aerosols with humidity, while the rest of the variability is in phase with the evolution of the sea-breeze cell. Local pollution is estimated to contribute 35±10% to the average aerosol optical depth at the Thessaloniki site during summer. Finally, the aerosol scale height was found to be related to the height of the boundary layer with values between 0.5–1 km during winter and up to 2.5–3 km during summer.

scholarly journals Physical and optical properties of aerosols over an urban location in Spain: seasonal and diurnal variability

2009 ◽  
Vol 9 (5) ◽  
pp. 18159-18199 ◽  
Author(s):  
H. Lyamani ◽  
F. J. Olmo ◽  
L. Alados-Arboledas
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Seasonal Cycle ◽  
Large Fraction ◽  
Particle Diameter ◽  
Urban Site ◽  
Number Density ◽  
Aerosol Optical Properties ◽  
Scattering Coefficients ◽  
Aerosol Absorption

Abstract. Measurements of aerosol optical properties and aerosol number size distribution obtained during the period from December 2005 to November 2007 at Granada, an urban site in south-eastern Spain, are analyzed. Large variations of the measured variables have been found, and related to variations in emissions sources and meteorological conditions. High values of aerosol absorption and scattering coefficients are obtained during winter and low values are measured during summer. This seasonal pattern in the surface aerosol optical properties is opposite to the seasonal cycle showed by columnar aerosol optical depth. The differences in the seasonal features of the surface and column-integrated data are related to seasonal variations in the aerosol vertical distribution, aerosol sources and boundary layer height. In winter the number density of fine particles (0.5<particle diameter<1μm) is significantly larger than in summer while the number density of coarse particles (1<particle diameter<20 μm) is slightly larger during summer and spring than during winter and autumn. The scattering Angström exponent, αs, presents an evident seasonal cycle with values of 1.8±0.2, 1.6±0.3, 1.3±0.3 and 1.4±0.3 in winter, spring, summer and autumn, respectively. This suggests the presence of a large fraction of submicron particles at the site, especially during winter. Urban aerosols in Granada contain a large fraction of absorbing material as indicated by the average single-scattering albedo that has values of 0.65±0.07, 0.66±0.06, 0.70±0.06 and 0.73±0.06 in autumn, winter, spring and summer, respectively. The aerosol scattering albedo obtained in the surface boundary layer of Granada is below the critical value of 0.86 that determines the shift from cooling to warming. These results put in evidence the need of efforts to reduce absorbing particles (black carbon) emissions to avoid the possible warming that would result from the reductions of the cooling aerosols only. The aerosol absorption and scattering coefficients present a clear diurnal pattern, in all seasons, with two local maxima, one early in the morning and the second one in the evening. This diurnal cycle is mainly attributed to the diurnal evolution of atmospheric boundary layer and local anthropogenic activities.

Optical Properties of Aerosol in Planetary Boundary Layer Measured by Raman Lidar at Hefei in Summer and Autumn

2010 ◽  
Vol 37 (10) ◽  
pp. 2526-2532 ◽  
Author(s):  
伯广宇 Bo Guangyu ◽  
谢晨波 Xie Chenbo ◽  
刘东 Liu Dong ◽  
陈涛 Chen Tao ◽  
王邦新 Wang Bangxin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Planetary Boundary Layer ◽  
Raman Lidar
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