Climatology of the Aerosol Extinction-to-Backscatter Ratio from Sun-Photometric Measurements

Pedrós, R.; Estellés, V.; Sicard, Michaël; Gómez-Amo, José Luís; Utrillas, M. P.; Martínez‐Lozano, J. A.; Rocadenbosch, Francesc; García‐Pando, Carlos Pérez; Recio, José María Baldasano

doi:10.1109/tgrs.2009.2027699

Cited by 16 publications

(14 citation statements)

References 66 publications

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“… Müller et al [2007] summarize a set of field campaigns, in which S at 532 nm was found to be from 23–29 for marine aerosol. Pedrós et al [2010] obtained median values of S at 532 nm of 31, 36, and 37 for air masses originating from different oceanic regions, although there may have been a local contribution to these results. The AERONET analysis of Smirnov et al [2003a] at Lanai gives 34.5 at 500 nm and 37 at 1020 nm.…”

Section: Lidar Ratiosmentioning

confidence: 78%

“…where P, the scattering phase function, is typically normalized to integrate to either 1 or 4p, and w 0 is the aerosol single scattering albedo; i.e., S is simply the ratio of total extinction to backscatter. As such for a given vertically-integrated backscatter, the calculated AOD is directly proportional to S. Depending on the characteristics of an individual lidar, S is either calculated from measured extinction and backscatter (for example, Pedrós et al [2010]), or prescribed as a function of aerosol type. In the latter situation the choice of an appropriate S is therefore important for the accurate calculation of aerosol loading.…”

Section: Lidar Ratiosmentioning

confidence: 99%

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A pure marine aerosol model, for use in remote sensing applications

et al. 2012

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[1] Retrievals of aerosol optical depth (AOD) and related parameters from satellite measurements typically involve prescribed models of aerosol size and composition, and are therefore dependent on how well these models are able to represent the radiative behavior of real aerosols. This study uses aerosol volume size distributions retrieved from Sun-photometer measurements at 11 Aerosol Robotic Network (AERONET) island sites, spread throughout the world's oceans, as a basis to define such a model for pure (unpolluted) maritime aerosol. Volume size distributions are observed to be bimodal and approximately lognormal, although the coarse mode is skewed with a long tail on the low-radius end. The relationship of AOD and size distribution parameters to meteorological conditions is also examined. As wind speed increases, so do coarse-mode volume and radius. The AOD and Ångström exponent show linear relationships with wind speed, although with considerable scatter. Links between aerosol properties and near-surface relative humidity, columnar water vapor, and sea surface temperature are also explored. A recommended bimodal maritime model, which is able to reconstruct the AERONET AOD with accuracy of order 0.01-0.02, is presented for use in aerosol remote sensing applications. This accuracy holds at most sites and for wavelengths between 340 nm and 1020 nm. Calculated lidar ratios are also provided, and are in the range of other studies, although differ more strongly from those currently used in Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) processing.

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Section: Lidar Ratiosmentioning

confidence: 78%

Section: Lidar Ratiosmentioning

confidence: 99%

A pure marine aerosol model, for use in remote sensing applications

et al. 2012

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“…They can complement the sunphotometer measurements by providing height-dependent measurements and helping to determine the aerosol characteristics at various heights of the atmospheric column (Mattis et al, 2004). Various research endeavors have been conducted by synergizing the LIDAR measurements with the sunphotometer measurements (Chazette, 2003;Pedrós et al, 2010). However, results from this approach poorly resemble the actual atmospheric conditions, as only a single-valued, range-independent atmospheric parameter is obtained, such as the LIDAR ratio, while in fact, there might be several atmospheric layers that exist in the atmosphere (Royer et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Vertical Profiling of Aerosol Types Observed across Monsoon Seasons with a Raman Lidar in Penang Island, Malaysia

Hee

Lim

Jafri

et al. 2016

Aerosol Air Qual. Res.

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Although technology has advanced in the past few decades, the understanding of the effect of aerosol on Earth's climate has remained largely unknown. Even if considerable effort has been made by researchers around the world to study this pressing issue, the non-uniform distribution of aerosols is still a huge challenge on global aerosol characterization studies. Without extensive and reliable measurements from most regions in the world, a complete understanding of aerosol characteristics cannot be achieved. In this study, a Raman LIDAR was used to acquire data to calculate the rangedependent extinction-to-backscattering ratio during a very particular period: when the Northeast monsoon season shifts to the Southwest monsoon season. During this time period, monsoonal winds change direction, leading to changes in aerosol type and properties above Penang Island due to the global atmospheric circulation. From the retrieved extinction-tobackscattering ratio, it is possible to differentiate the aerosol types present at various altitudes. It was found that background marine and urban aerosols were present above Penang Island, as marine and urban aerosols were present both below and above the PBL height regardless of the monsoon season. Additionally, biomass burning aerosols and aged forest fire aerosols were occasionally found, which were normally associated with cases of pollution, such as those in early March 2014 and June 2014. Finally, it was found that during a haze episode, the entire atmospheric column was dominated by wood burning aerosols. AERONET sunphotometer data have been used to validate LIDAR findings. Radiative effect of background and transported aerosols are evaluated with the Fu-Liou-Gu radiative transfer model.

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“…Thus the AODs obtained by these two methods are compared, and a lidar ratio value is selected when the differences are minimized [ Guerrero ‐ Rascado et al , 2008]. According to Pedrós et al [2009], a worst case estimate of the uncertainty associated with the lidar ratio is 10%. After deriving the backscatter coefficient profiles using the appropriate lidar ratio, we compute other properties such as the backscatter‐related Ångström exponent profiles.…”

Section: Methodsmentioning

confidence: 99%

Aerosol closure study by lidar, Sun photometry, and airborne optical counters during DAMOCLES field campaign at El Arenosillo sounding station, Spain

Guerrero-Rascado¹,

Andrey²,

Sicard³

et al. 2011

J. Geophys. Res.

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[1] We present a comparison of aerosol properties derived from in situ and remote sensing instruments during DAMOCLES campaign, aimed at investigating the equivalence between the instrumentation and methodologies employed by several Spanish groups to study atmospheric aerosols at a regional background site. The complete set of instruments available during this closure experiment allowed collecting a valuable high-resolution aerosol measurement data set. The data set was augmented with airborne in situ measurements carried out in order to characterize aerosol particles during the midday of 29 June 2006. This work is focused on aerosol measurements using different techniques of high-quality instruments (ground-based remote sensing and aircraft in situ) and their comparisons to characterize the aerosol vertical profiles. Our results indicate that the variability between the detected aerosol layers was negligible in terms of aerosol optical properties and size distributions. Relative differences in aerosol extinction coefficient profiles were less than 20% at 355 and 532 nm and less than 30% at 1064 nm, in the region with high aerosol concentration. Absolute differences in aerosol optical depth (AOD) were below 0.01 at 532 and 1064 nm and less than 0.02 at 355 nm, less than the uncertainties assumed in the AOD obtained from elastic lidar. Columnar values of the lidar ratio revealed some discrepancies with respect to the in situ aircraft measurements, caused fundamentally by the lack of information in the lowest part of the boundary layer.

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Climatology of the Aerosol Extinction-to-Backscatter Ratio from Sun-Photometric Measurements

Abstract: Abstract-The elastic lidar equation contains two unknown atmospheric parameters, namely, the particulate optical extinction and backscatter coefficients, which are related through the lidar ratio (i.e., the particulate-extinction-to-backscatter ratio).

Cited by 16 publications

References 66 publications

A pure marine aerosol model, for use in remote sensing applications

A pure marine aerosol model, for use in remote sensing applications

Vertical Profiling of Aerosol Types Observed across Monsoon Seasons with a Raman Lidar in Penang Island, Malaysia

Aerosol closure study by lidar, Sun photometry, and airborne optical counters during DAMOCLES field campaign at El Arenosillo sounding station, Spain

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