Measurement of ocean water optical properties and seafloor reflectance with scanning hydrographic operational airborne lidar survey (SHOALS): II. Practical results and comparison with independent data

2005 ◽  
Author(s):  
Grady H. Tuell ◽  
Viktor Feygels ◽  
Yuri Kopilevich ◽  
Alan D. Weidemann ◽  
A. Grant Cunningham ◽  
...  
Keyword(s):  
Optical Properties ◽  
Airborne Lidar ◽  
Independent Data ◽  
Ocean Water

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 3D Ocean Water Wave Surface Analysis on Airborne LiDAR Bathymetric Point Clouds

2021 ◽  
Vol 13 (19) ◽  
pp. 3918
Author(s):  
Sajjad Roshandel ◽  
Weiquan Liu ◽  
Cheng Wang ◽  
Jonathan Li
Keyword(s):  
Water Wave ◽  
Large Scale ◽  
Spatial Clustering ◽  
Point Clouds ◽  
Airborne Lidar ◽  
Coastal Hazards ◽  
Ocean Water ◽  
Coastal Zones ◽  
Wave Surface ◽  
Dbscan Clustering

Water wave monitoring is a vital issue for coastal research and plays a key role in geomorphological changes, erosion and sediment transportation, coastal hazards, risk assessment, and decision making. However, despite missing data and the difficulty of capturing the data of nearshore fieldwork, the analysis of water wave surface parameters is still able to be discussed. In this paper, we propose a novel approach for accurate detection and analysis of water wave surface from Airborne LiDAR Bathymetry (ALB) large-scale point clouds data. In our proposed method we combined the modified Density-Based Spatial Clustering of Applications with Noise (DBSCAN) clustering method with a connectivity constraint and a multi-level analysis of ocean water surface. We adapted for most types of wave shape anatomies in shallow waters, nearshore, and onshore of the coastal zone. We used a wavelet analysis filter to detect the water wave surface. Then, through the Fourier Transformation Approach, we estimated the parameters of wave height, wavelength, and wave orientation. The comparison between the LiDAR measure estimation technique and available buoy data was then presented. We quantified the performance of the algorithm by measuring the precision and recall for the waves identification without evaluating the degree of over-segmentation. The proposed method achieves 87% accuracy of wave identification in the shallow water of coastal zones.

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 Energy Gap Evaluation in Microcrystalline m-HfO2 Powder

2021 ◽  
pp. 226-231
Author(s):  
Artem O. Shilov ◽  
Sergey S. Savchenko ◽  
Alexander S. Vokhmintsev ◽  
Andrey V. Chukin ◽  
Maksim S. Karabanalov ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Optical Properties ◽  
Monoclinic Phase ◽  
Diffuse Reflectance ◽  
Energy Gap ◽  
Independent Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Russian Scientific

In this paper optical properties of microcrystalline HfO2 powder are investigated. X-ray diffraction and Raman spectroscopy were used to determine that the studied samples are in monoclinic phase. Based on the analysis of the diffuse reflectance spectra and applying Kubelka-Munk formalism we evaluated the indirect bandgap value Eg = 5.34 ± 0.05 eV. The calculated value is in agreement with independent data for HfO2 thin films synthesized by various methods. The paper is based on the materials of the report presented at the first Russian scientific confererence with the participation of the international community "YENISEI PHOTONICS – 2020"

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