Characterising the long‐range transport mechanisms of different aerosol types over Athens, Greece during 2000–2005

Kaskaoutis, Dimitris G.; Nastos, Panagiotis T.; Kosmopoulos, Panagiotis; Kambezidis, H. D.

doi:10.1002/joc.2357

Cited by 31 publications

(16 citation statements)

References 84 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As a result, this sample was influenced by the Iberian Peninsula's PBL, in addition to the large amount of Saharan dust present at this time (Fig. 4B) which was previously transported by air masses at higher altitudes 33 .…”

Section: Samples Collected and Microscopic Analysismentioning

confidence: 96%

“…4A). Thus, those coming from North Africa (Feb 22-23) experienced strong vertical mixing with different atmospheric layers, including the Saharan Planetary boundary layer (PBL) 33,59 . On Feb 24, the wind pattern changed above the Iberian Peninsula, rotating to north-northwesterly winds; as a result, the origin of air masses was originated in the Atlantic Ocean for this particular day.…”

Section: Samples Collected and Microscopic Analysismentioning

confidence: 99%

See 1 more Smart Citation

Impacts of Saharan Dust Intrusions on Bacterial Communities of the Low Troposphere

González-Toril

Osuna

Viúdez‐Moreiras

et al. 2020

Sci Rep

View full text Add to dashboard Cite

We have analyzed the bacterial community of a large Saharan dust event in the iberian peninsula and, for the first time, we offer new insights regarding the bacterial distribution at different altitudes of the lower troposphere and the replacement of the microbial airborne structure as the dust event receeds. Samples from different open-air altitudes (surface, 100 m and 3 km), were obtained onboard the National Institute for Aerospace Technology (INTA) C-212 aircrafts. Samples were collected during dust and dust-free air masses as well two weeks after the dust event. Samples related in height or time scale seems to show more similar community composition patterns compared with unrelated samples. The most abundant bacterial species during the dust event, grouped in three different phyla: (a) Proteobacteria: Rhizobiales, Sphingomonadales, Rhodobacterales, (b) Actinobacteria: Geodermatophilaceae; (c) Firmicutes: Bacillaceae. Most of these taxa are well known for being extremely stress-resistant. After the dust intrusion, Rhizobium was the most abundant genus, (40-90% total sequences). Samples taken during the flights carried out 15 days after the dust event were much more similar to the dust event samples compared with the remaining samples. in this case, Brevundimonas, and Methylobacterium as well as Cupriavidus and Mesorizobium were the most abundant genera.Airborne microbes are ubiquitous in the atmosphere 1 and are thought to play important roles in meteorological processes (i.e. clouds and snow formation or precipitation patterns alterations) 2,3 , as well as in the long-range dispersal of plant and livestock pathogens 4,5 and in the maintenance of the diversity in aquatic systems 6 . Likewise, airborne bacteria can have important effects on human health, producing allergic asthma and seasonal allergies, and could interfere in the productivity of managed and natural ecosystems 7 . Global abundance of aerial microorganisms has been estimated, based on data from terrestrial environments, to range between 10 4 to 10 6 m −3 8 . However, more recent studies, incorporating direct counting by microscopy or quantitative PCR 9 , have yielded, more accurate, higher estimates of the abundance of airborne microbes and seasonal patterns 10 . Additionally, the atmosphere is one of the most extreme environments and microorganisms inhabiting in the troposphere are exposed to higher UV radiation, desiccation, cold temperatures and nutrient deprivation than in other environments 11,12 .Several studies have also demonstrated the potential for microorganisms to be transported over long distances through the atmosphere, associated to desert dust, as a route for the colonization of new habitats 13,14 . Thus, desert dust clouds may serve not only as a source of nutrients for terrestrial plants and primary producers in nutrient depleted oceanic waters 15,16 , but may also serve as a vehicle for global transport of microorganisms, including pathogens 13,17 .The Sahara-Sahel regions of North Africa are the dominant sources of aerosolize...

show abstract

Section: Samples Collected and Microscopic Analysismentioning

confidence: 96%

Section: Samples Collected and Microscopic Analysismentioning

confidence: 99%

Impacts of Saharan Dust Intrusions on Bacterial Communities of the Low Troposphere

González-Toril

Osuna

Viúdez‐Moreiras

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…There are numerous studies that have used either satellite products only or in combination with ground-based observations to estimate regional and global AOD (e.g. Papadimas et al, 2009;Kaskaoutis et al, 2011). Most studies have used satellite AOD products that refer to aerosol load, which is the aerosol amount integrated from the surface to the top of atmosphere.…”

Section: Pappas Et Al: Evaluation Of Spatio-temporal Variability mentioning

confidence: 99%

Evaluation of spatio-temporal variability of Hamburg Aerosol Climatology against aerosol datasets from MODIS and CALIOP

Pappas¹,

Hatzianastassiou²,

Papadimas³

et al. 2013

Preprint

View full text Add to dashboard Cite

The new global aerosol climatology named HAC (Hamburg Aerosol Climatology) is compared against MODIS (MODerate resolution Imaging Spectroradiometer, Collection 5, 2000–2007) and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization, Level 2-Version 3, 2006–2011) retrievals. The HAC aerosol optical depth (AOD) values are larger than MODIS in heavy aerosol load conditions (over land) and lower over oceans. Agreement between HAC and MODIS is better over land and for low AOD. Hemispherically, HAC has 16–17% smaller AOD values than MODIS. The discrepancy is slightly larger for the Southern Hemisphere (SH) than for the Northern Hemisphere (NH). Seasonally, the largest absolute differences are from March to August for NH and from September to February for SH. The spectral variability of HAC AOD is also evaluated against AERONET (1998–2007) data for sites representative of main aerosol types (pollutants, sea-salt, biomass and dust). The HAC has a stronger spectral dependence of AOD in the UV wavelengths, compared to AERONET and MODIS. For visible and near-infrared wavelengths, the spectral dependence is similar to AERONET. For specific sites, HAC AOD vertical distribution is compared to CALIOP data by looking at the fraction of columnar AOD at each altitude. The comparison suggests that HAC exhibits a smaller fraction of columnar AOD in the lowest 2–3 km than CALIOP, especially for sites with biomass burning smoke, desert dust and sea salt spray. For the region of the greater Mediterranean basin, the mean profile of HAC AOD is in very good agreement with CALIOP. The HAC AOD is very useful for distinguishing between natural and anthropogenic aerosols and provides high spectral resolution and vertically resolved information

show abstract

“…Hence the ability to differentiate particles with respect to their size can provide a mean to quantify the influence of human activities on the abundance of atmospheric aerosols. Separating contributions from smaller and bigger particles in aerosol optical depth (AOD) is a step forward in this direction and can serve as a proxy to study many of the effects discussed above (Kosmopoulos et al, 2008;Lee et al, 2010;Kaskaoutis et al, 2012;Sinha et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Role of Coarse and Fine Mode Aerosols in MODIS AOD Retrieval: a case study over southern India

et al. 2014

View full text Add to dashboard Cite

Abstract. In the present study we compare the MODIS (Moderate Resolution Imaging Spectroradiometer) derived aerosol optical depth (AOD) data with that obtained from operating sky-radiometer at a remote rural location in southern India (Gadanki, 13.45 • N, 79.18 • E) from April 2008 to March 2011. While the comparison between total (coarse mode + fine mode) AODs shows correlation coefficient (R) value of about 0.71 for Terra and 0.77 for Aqua, if one separates the AOD into fine and coarse mode, the comparison becomes very poor, particularly for fine mode with an R value of 0.44 for both Terra and Aqua. The coarse mode AOD derived from MODIS and sky-radiometer compare better with an R value of 0.74 for Terra and 0.66 for Aqua. The seasonal variation is also well captured by both ground-based and satellite measurements. It is shown that both the total AOD and fine mode AOD are significantly underestimated with slope of regression line 0.75 and 0.35 respectively, whereas the coarse mode AOD is overestimated with a slope value of 1.28 for Terra. Similar results are found for Aqua where the slope of the regression line for total AOD and fine mode AOD are 0.72 and 0.27 whereas 0.95 for coarse mode. The fine mode fraction derived from MODIS data is less than one-half of that derived from the sky-radiometer data. Based on these observations and comparison of single scattering albedo observed using sky-radiometer with that of MODIS aerosol models, we argue that the selection of aerosol types used in the MODIS retrieval algorithm may not be appropriate particularly in the case of southern India. Instead of selecting a moderately absorbing aerosol model (as being done currently in the MODIS retrieval) a more absorbing aerosol model could be a better fit for the fine mode aerosols, while reverse is true for the coarse mode aerosols, where instead of using "dust aerosols" which is relatively absorbing type, usage of coarse sea-salt particles which is less absorbing is more appropriate. However, not all the differences could be accounted based on aerosol model, other factors like errors in retrieval of surface reflectance may also be significant in causing underestimation of AOD by MODIS.

show abstract

Characterising the long‐range transport mechanisms of different aerosol types over Athens, Greece during 2000–2005

Cited by 31 publications

References 84 publications

Impacts of Saharan Dust Intrusions on Bacterial Communities of the Low Troposphere

Impacts of Saharan Dust Intrusions on Bacterial Communities of the Low Troposphere

Evaluation of spatio-temporal variability of Hamburg Aerosol Climatology against aerosol datasets from MODIS and CALIOP

Role of Coarse and Fine Mode Aerosols in MODIS AOD Retrieval: a case study over southern India

Contact Info

Product

Resources

About