Author
Carlos Toledano
Other affiliations: Ludwig Maximilian University of Munich
Bio: Carlos Toledano is an academic researcher from University of Valladolid. The author has contributed to research in topics: AERONET & Aerosol. The author has an hindex of 33, co-authored 128 publications receiving 3701 citations. Previous affiliations of Carlos Toledano include Ludwig Maximilian University of Munich.
Topics: AERONET, Aerosol, Sun photometer, Angstrom exponent, Mineral dust
Papers published on a yearly basis
Papers
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TL;DR: In this paper, the vertical profiles of the linear particle depolarization ratio of pure dust clouds were measured during the Saharan Mineral Dust Experiment (SAMUM) at Ouarzazate, Morocco, close to source regions in May-June 2006, with four lidar systems at four wavelengths (355, 532, 710 and 1064 nm).
Abstract: Vertical profiles of the linear particle depolarization ratio of pure dust clouds were measured during the Saharan Mineral Dust Experiment (SAMUM) at Ouarzazate, Morocco (30.9 ◦ N, –6.9 ◦ E), close to source regions in May–June 2006, with four lidar systems at four wavelengths (355, 532, 710 and 1064 nm). The intercomparison of the lidar systems is accompanied by a discussion of the different calibration methods, including a new, advanced method, and a detailed error analysis. Over the whole SAMUM periode pure dust layers show a mean linear particle depolarization ratio at 532 nm of 0.31, in the range between 0.27 and 0.35, with a mean Angstr¨ om exponent (AE, 440–870 nm) of 0.18 (range 0.04–0.34) and still high mean linear particle depolarization ratio between 0.21 and 0.25 during periods with aerosol optical thickness less than 0.1, with a mean AE of 0.76 (range 0.65–1.00), which represents a negative correlation of the linear particle depolarization ratio with the AE. A slight decrease of the linear particle depolarization ratio with wavelength was found between 532 and 1064 nm from 0.31 ± 0.03 to 0.27 ± 0.04.
482 citations
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TL;DR: In this paper, the particle linear depolarization ratio of Saharan dust, marine aerosols and mixtures of biomass-burning aerosols from southern West Africa and Saharan Dust was determined at three wavelengths with three lidar systems during the SAharan Mineral dUst experiMent 2 at the airport of Praia, Cape Verde, between 22 January and 9 February 2008.
Abstract: The particle linear depolarization ratio δ p of Saharan dust, marine aerosols and mixtures of biomass-burning aerosols from southern West Africa and Saharan dust was determined at three wavelengths with three lidar systems during the SAharan Mineral dUst experiMent 2 at the airport of Praia, Cape Verde, between 22 January and 9 February 2008. The lidar ratio S p of these major types of tropospheric aerosols was analysed at two wavelengths. For Saharan dust, we find wavelength dependent mean particle linear depolarization ratios δ p of 0.24–0.27 at 355 nm, 0.29–0.31 at 532 nm and 0.36–0.40 at 710 nm, and wavelength independent mean lidar ratios S p of 48–70 sr. Mixtures of biomass-burning aerosols and dust show wavelength independent values of δ p and S p between 0.12–0.23 and 57–98 sr, respectively. The mean values of marine aerosols range independent of wavelength for δ p from 0.01 to 0.03 and for S p from 14 to 24 sr. DOI: 10.1111/j.1600-0889.2011.00556.x
239 citations
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National Oceanic and Atmospheric Administration1, Environment Canada2, Arctic and Antarctic Research Institute3, University of Bremen4, Norwegian Institute for Air Research5, Finnish Meteorological Institute6, Stockholm University7, University of Valladolid8, Polish Academy of Sciences9, National Institute of Polar Research10
TL;DR: In this paper, large sets of filtered actinometer, filtered pyrheliometer and Sun photometer measurements have been carried out over the past 30 years by various groups at different Arctic and Antarctic sites and...
Abstract: Large sets of filtered actinometer, filtered pyrheliometer and Sun photometer measurements have been carried out over the past 30 years by various groups at different Arctic and Antarctic sites and ...
203 citations
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TL;DR: The Saharan Aerosol Long-range Transport and Aerosols-Cloud-Interaction Experiment (SALTRACE) as discussed by the authors linked ground-based and airborne measurements with remote sensing and modeling techniques to address these issues.
Abstract: North Africa is the world’s largest source of dust, a large part of which is transported across the Atlantic to the Caribbean and beyond where it can impact radiation and clouds. Many aspects of this transport and its climate effects remain speculative. The Saharan Aerosol Long-Range Transport and Aerosol–Cloud-Interaction Experiment (SALTRACE; www.pa.op.dlr.de/saltrace) linked ground-based and airborne measurements with remote sensing and modeling techniques to address these issues in a program that took place in 2013/14. Specific objectives were to 1) characterize the chemical, microphysical, and optical properties of dust in the Caribbean, 2) quantify the impact of physical and chemical changes (“aging”) on the radiation budget and cloud microphysical processes, 3) investigate the meteorological context of transatlantic dust transport, and 4) assess the roles of removal processes during transport.SALTRACE was a German-led initiative involving scientists from Europe, Cabo Verde, the Caribbean, a...
187 citations
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TL;DR: In this paper, two basic parameters for aerosol characterization, aerosol optical depth (AOD) and Angstrom exponent, α, are used for analysis of aerosol data.
Abstract: Routine aerosol measurements have been carried out at INTA–El Arenosillo (Huelva, Spain) since February 2000 with a Cimel sun photometer integrated in the global aerosol monitoring network AERONET. A 5-year aerosol database allows characterization and classification of aerosol properties, which define the local aerosol climatology. In this work two basic parameters for aerosol characterization, aerosol optical depth (AOD) and Angstrom exponent, α, are used for aerosol analysis. The mean AOD is 0.18 ( ± 0.14) and the mean α is 1.05 ( ± 0.43). The AOD presents two peaks during the year, at the end of the winter and during the summer, which are related to the seasonal patterns of the desert dust aerosols which arrive at the south-western Iberian Peninsula from North Africa. The Angstrom exponent presents two frequency modes, related to the two main aerosol types present at El Arenosillo: coastal marine aerosols and desert dust. A main aerosol scenario (66% of data) is defined as coastal marine aerosols, with the influence of local sources of continental and polluted aerosols. Continental aerosols are present in 11% of cases, while the desert dust has a very relevant occurrence in around 20% of the data. Copyright © 2007 Royal Meteorological Society
180 citations
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TL;DR: In this article, the authors present a document, redatto, voted and pubblicato by the Ipcc -Comitato intergovernativo sui cambiamenti climatici - illustra la sintesi delle ricerche svolte su questo tema rilevante.
Abstract: Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.
4,187 citations
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TL;DR: The AERONET Version 3.3.V3 (V3) algorithm as mentioned in this paper provides fully automatic cloud screening and instrument anomaly quality control for near real-time AOD data.
Abstract: The Aerosol Robotic Network (AERONET) has provided highly
accurate, ground-truth measurements of the aerosol optical depth (AOD) using
Cimel Electronique Sun–sky radiometers for more than 25 years In Version 2 (V2)
of the AERONET database, the near-real-time AOD was semiautomatically
quality controlled utilizing mainly cloud-screening methodology, while
additional AOD data contaminated by clouds or affected by instrument
anomalies were removed manually before attaining quality-assured status
(Level 20) The large growth in the number of AERONET sites over the past
25 years resulted in significant burden to the manual quality control of millions
of measurements in a consistent manner The AERONET Version 3 (V3) algorithm
provides fully automatic cloud screening and instrument anomaly quality
controls All of these new algorithm updates apply to near-real-time data as
well as post-field-deployment processed data, and AERONET reprocessed the
database in 2018 A full algorithm redevelopment provided the opportunity to
improve data inputs and corrections such as unique filter-specific
temperature characterizations for all visible and near-infrared wavelengths,
updated gaseous and water vapor absorption coefficients, and ancillary data
sets The Level 20 AOD quality-assured data set is now available within a
month after post-field calibration, reducing the lag time from up to several
months Near-real-time estimated uncertainty is determined using data
qualified as V3 Level 20 AOD and considering the difference between the AOD
computed with the pre-field calibration and AOD computed with pre-field and
post-field calibration This assessment provides a near-real-time
uncertainty estimate for which average differences of AOD suggest a +002 bias
and one sigma uncertainty of 002, spectrally, but the bias and uncertainty
can be significantly larger for specific instrument deployments Long-term
monthly averages analyzed for the entire V3 and V2 databases produced
average differences (V3–V2) of + 0002 with a ± 002 SD (standard
deviation), yet monthly averages calculated using time-matched observations
in both databases were analyzed to compute an average difference of −0002
with a ±0004 SD The high statistical agreement in
multiyear monthly averaged AOD validates the advanced automatic data
quality control algorithms and suggests that migrating research to the
V3 database will corroborate most V2 research conclusions and likely lead to
more accurate results in some cases
629 citations
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TL;DR: The Southern Hemisphere climate system varies on timescales from orbital, through millennial to sub-annual, and is closely coupled to other parts of the global climate system as discussed by the authors.
Abstract: The Antarctic climate system varies on timescales from orbital, through millennial to sub-annual, and is closely coupled to other parts of the global climate system. We review these variations from the perspective of the geological and glaciological records and the recent historical period from which we have instrumental data (the last 50 years). We consider their consequences for the biosphere, and show how the latest numerical models project changes into the future, taking into account human actions in the form of the release of greenhouse gases and chlorofluorocarbons into the atmosphere. In doing so, we provide an essential Southern Hemisphere companion to the Arctic Climate Impact Assessment.
559 citations
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TL;DR: In this paper, the authors compare the performance of the Enhanced Deep Blue (DB) and Dark Target (DT) algorithms over land, and a DT over-water algorithm over desert/urban areas.
Abstract: The Moderate Resolution Imaging Spectroradiometer (MODIS) Atmospheres data product suite includes three algorithms applied to retrieve midvisible aerosol optical depth (AOD): the Enhanced Deep Blue (DB) and Dark Target (DT) algorithms over land, and a DT over-water algorithm. All three have been refined in the recent “Collection 6” (C6) MODIS reprocessing. In particular, DB has been expanded to cover vegetated land surfaces as well as brighter desert/urban areas. Additionally, a new “merged” data set which draws from all three algorithms is included in the C6 products. This study is intended to act as a point of reference for new and experienced MODIS data users with which to understand the global and regional characteristics of the C6 DB, DT, and merged data sets, based on MODIS Aqua data. This includes validation against Aerosol Robotic Network (AERONET) observations at 111 sites, focused toward regional and categorical (surface/aerosol type) analysis. Neither algorithm consistently outperforms the other, although in many cases the retrieved AOD and the level of its agreement with AERONET are very similar. In many regions the DB, DT, and merged data sets are all suitable for quantitative applications, bearing in mind that they cannot be considered independent, while in other cases one algorithm does consistently outperform the other. Usage recommendations and caveats are thus somewhat complicated and regionally dependent.
534 citations
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TL;DR: The global cycle of desert dust aerosols responds strongly to climate and human perturbations, and, in turn, impacts climate and biogeochemistry as discussed by the authors, focusing on desert dust size distributions, how these are characterized, emitted from the surface, evolve in the atmosphere, and impact climate.
484 citations