Measurement of ocean optical properties profiles using airborne lidar (Conference Presentation)

2018 ◽  
Author(s):  
Hang Liu ◽  
Peng Chen ◽  
Zhihua Mao ◽  
Yan He ◽  
Difeng Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Airborne Lidar

scholarly journals Airborne lidar measurements of aerosol spatial distribution and optical properties over the Atlantic Ocean during a European pollution outbreak of ACE-2

Tellus B ◽  
2000 ◽  
Vol 52 (2) ◽  
pp. 662-677 ◽  
Author(s):  
Cyrille Flamant ◽  
Jacques Pelon ◽  
Patrick Chazette ◽  
Vincent Trouillet ◽  
Patricia K. Quinn ◽  
...  
Keyword(s):  
Optical Properties ◽  
Spatial Distribution ◽  
Atlantic Ocean ◽  
Airborne Lidar ◽  
Lidar Measurements

scholarly journals Modeling the smoky troposphere of the southeast Atlantic: a comparison to ORACLES airborne observations from September of 2016

2020 ◽  
Vol 20 (19) ◽  
pp. 11491-11526 ◽  
Author(s):  
Yohei Shinozuka ◽  
Pablo E. Saide ◽  
Gonzalo A. Ferrada ◽  
Sharon P. Burton ◽  
Richard Ferrare ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Black Carbon ◽  
Marine Boundary Layer ◽  
Organic Aerosol ◽  
Airborne Lidar ◽  
Aerosol Mass ◽  
Wide Range ◽  
Smoke Layer ◽  
Mass Concentrations

Abstract. In the southeast Atlantic, well-defined smoke plumes from Africa advect over marine boundary layer cloud decks; both are most extensive around September, when most of the smoke resides in the free troposphere. A framework is put forth for evaluating the performance of a range of global and regional atmospheric composition models against observations made during the NASA ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) airborne mission in September 2016. A strength of the comparison is a focus on the spatial distribution of a wider range of aerosol composition and optical properties than has been done previously. The sparse airborne observations are aggregated into approximately 2∘ grid boxes and into three vertical layers: 3–6 km, the layer from cloud top to 3 km, and the cloud-topped marine boundary layer. Simulated aerosol extensive properties suggest that the flight-day observations are reasonably representative of the regional monthly average, with systematic deviations of 30 % or less. Evaluation against observations indicates that all models have strengths and weaknesses, and there is no single model that is superior to all the others in all metrics evaluated. Whereas all six models typically place the top of the smoke layer within 0–500 m of the airborne lidar observations, the models tend to place the smoke layer bottom 300–1400 m lower than the observations. A spatial pattern emerges, in which most models underestimate the mean of most smoke quantities (black carbon, extinction, carbon monoxide) on the diagonal corridor between 16∘ S, 6∘ E, and 10∘ S, 0∘ E, in the 3–6 km layer, and overestimate them further south, closer to the coast, where less aerosol is present. Model representations of the above-cloud aerosol optical depth differ more widely. Most models overestimate the organic aerosol mass concentrations relative to those of black carbon, and with less skill, indicating model uncertainties in secondary organic aerosol processes. Regional-mean free-tropospheric model ambient single scattering albedos vary widely, between 0.83 and 0.93 compared with in situ dry measurements centered at 0.86, despite minimal impact of humidification on particulate scattering. The modeled ratios of the particulate extinction to the sum of the black carbon and organic aerosol mass concentrations (a mass extinction efficiency proxy) are typically too low and vary too little spatially, with significant inter-model differences. Most models overestimate the carbonaceous mass within the offshore boundary layer. Overall, the diversity in the model biases suggests that different model processes are responsible. The wide range of model optical properties requires further scrutiny because of their importance for radiative effect estimates.

scholarly journals Airborne lidar measurements of aerosol optical properties during SAFARI-2000

2003 ◽  
Vol 108 (D13) ◽  
pp. n/a-n/a ◽  
Author(s):  
Matthew J. McGill ◽  
Dennis L. Hlavka ◽  
William D. Hart ◽  
Ellsworth J. Welton ◽  
James R. Campbell
Keyword(s):  
Optical Properties ◽  
Airborne Lidar ◽  
Aerosol Optical Properties ◽  
Lidar Measurements

scholarly journals Airborne measurements of aerosol optical properties related to early spring transport of mid-latitude sources into the Arctic

2009 ◽  
Vol 9 (6) ◽  
pp. 27791-27836 ◽  
Author(s):  
R. Adam de Villiers ◽  
G. Ancellet ◽  
J. Pelon ◽  
B. Quennehen ◽  
A. Scharwzenboeck ◽  
...  
Keyword(s):  
Optical Properties ◽  
Airborne Lidar ◽  
The Arctic ◽  
Aerosol Optical Properties ◽  
Accumulation Mode ◽  
Airborne Measurements ◽  
Depolarisation Ratio ◽  
Color Ratio ◽  
Aerosol Sources

Abstract. Airborne lidar and in-situ measurements of the aerosol properties were conducted between Svalbard Island and Scandinavia in April 2008. Evidence of aerosol transport from Europe and Asia is given. The analysis of the aerosol optical properties based on a multiwavelength lidar (355, 532, 1064 nm) including depolarization at 355 nm aims at distinguishing the role of the different aerosol sources (Siberian wild fires, Eastern Asia and European anthropogenic emissions). Combining, first aircraft measurements, second FLEXPART simulations with a calculation of the PBL air fraction originating from the three different mid-latitude source regions, and third level-2 CALIPSO data products (i.e. backscatter coefficient, depolarisation and color ratio in aerosol layers) along the transport pathways, appears a valuable approach to identify the role of the different aerosol sources even after a transport time larger than 4 days. Above Asia, CALIPSO data indicate more depolarisation (up to 15%) and largest color ratio (>0.5) for the northeastern Asia emissions (i.e. an expected mixture of Asian pollution and dust), while low depolarisation together with smaller and quasi constant color ratio (≈0.3) are observed for the Siberian biomass burning emissions. A similar difference is visible between two layers observed by the aircraft above Scandinavia. The analysis of the time evolution of the aerosol optical properties revealed by CALIPSO between Asia and Scandinavia shows a gradual decrease of the aerosol backscatter, depolarisation ratio and color ratio which suggests the removal of the largest particles in the accumulation mode. A similar study conducted for a European plume has shown aerosol optical properties intermediate between the two Asian sources with color ratio never exceeding 0.4 and moderate depolarisation ratio being always less than 8%, i.e. less aerosol from the accumulation mode.

scholarly journals Airborne lidar measurements of aerosol spatial distribution and optical properties over the Atlantic Ocean during a European pollution outbreak of ACE-2

Tellus B ◽  
2000 ◽  
Vol 52 (2) ◽  
pp. 662-677 ◽  
Author(s):  
Cyrille Flamant ◽  
Jacques Pelon ◽  
Patrick Chazette ◽  
Vincent Trouillet ◽  
Patricia K. Quinn ◽  
...  
Keyword(s):  
Optical Properties ◽  
Spatial Distribution ◽  
Atlantic Ocean ◽  
Airborne Lidar ◽  
Lidar Measurements

scholarly journals Statistics of Cloud Optical Properties from Airborne Lidar Measurements

2011 ◽  
Vol 28 (7) ◽  
pp. 869-883 ◽  
Author(s):  
John E. Yorks ◽  
Dennis L. Hlavka ◽  
William D. Hart ◽  
Matthew J. McGill
Keyword(s):  
Optical Properties ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Transmission Loss ◽  
Geographic Location ◽  
Airborne Lidar ◽  
Optical Parameters ◽  
Depolarization Ratio ◽  
Ice Clouds ◽  
Lidar Ratio

Abstract Accurate knowledge of cloud optical properties, such as extinction-to-backscatter ratio and depolarization ratio, can have a significant impact on the quality of cloud extinction retrievals from lidar systems because parameterizations of these variables are often used in nonideal conditions to determine cloud phase and optical depth. Statistics and trends of these optical parameters are analyzed for 4 yr (2003–07) of cloud physics lidar data during five projects that occurred in varying geographic locations and meteorological seasons. Extinction-to-backscatter ratios (also called lidar ratios) are derived at 532 nm by calculating the transmission loss through the cloud layer and then applying it to the attenuated backscatter profile in the layer, while volume depolarization ratios are computed using the ratio of the parallel and perpendicular polarized 1064-nm channels. The majority of the cloud layers yields a lidar ratio between 10 and 40 sr, with the lidar ratio frequency distribution centered at 25 sr for ice clouds and 16 sr for altocumulus clouds. On average, for ice clouds the lidar ratio slightly decreases with decreasing temperature, while the volume depolarization ratio increases significantly as temperatures decrease. Trends for liquid water clouds (altocumulus clouds) are also observed. Ultimately, these observed trends in optical properties, as functions of temperature and geographic location, should help to improve current parameterizations of extinction-to-backscatter ratio, which in turn should yield increased accuracy in cloud optical depth and radiative forcing estimates.

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