An outstanding Saharan dust event at Mt. Cimone (2165 m a.s.l., Italy) in March 2004

We report on a long-lasting (10 days) Saharan dust event affecting large sections of South-Eastern Europe by using a synergy of lidar, satellite, in-situ observations and model simulations over Athens, Greece. The dust measurements (11–20 May 2020), performed during the confinement period due to the COVID-19 pandemic, revealed interesting features of the aerosol dust properties in the absence of important air pollution sources over the European continent. During the event, moderate aerosol optical depth (AOD) values (0.3–0.4) were observed inside the dust layer by the ground-based lidar measurements (at 532 nm). Vertical profiles of the lidar ratio and the particle linear depolarization ratio (at 355 nm) showed mean layer values of the order of 47 ± 9 sr and 28 ± 5%, respectively, revealing the coarse non-spherical mode of the probed plume. The values reported here are very close to pure dust measurements performed during dedicated campaigns in the African continent. By utilizing Libradtran simulations for two scenarios (one for typical midlatitude atmospheric conditions and one having reduced atmospheric pollutants due to COVID-19 restrictions, both affected by a free tropospheric dust layer), we revealed negligible differences in terms of radiative effect, of the order of +2.6% (SWBOA, cooling behavior) and +1.9% (LWBOA, heating behavior). Moreover, the net heating rate (HR) at the bottom of the atmosphere (BOA) was equal to +0.156 K/d and equal to +2.543 K/d within 1–6 km due to the presence of the dust layer at that height. On the contrary, the reduction in atmospheric pollutants could lead to a negative HR (−0.036 K/d) at the bottom of the atmosphere (BOA) if dust aerosols were absent, while typical atmospheric conditions are estimated to have an almost zero net HR value (+0.006 K/d). The NMMB-BSC forecast model provided the dust mass concentration over Athens, while the air mass advection from the African to the European continent was simulated by the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model.

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WRF-chem sensitivity to vertical resolution during a saharan dust event

Physics and Chemistry of the Earth Parts A/B/C ◽

10.1016/j.pce.2015.04.002 ◽

2016 ◽

Vol 94 ◽

pp. 188-195 ◽

Cited By ~ 13

Author(s):

J.C. Teixeira ◽

A.C. Carvalho ◽

Paolo Tuccella ◽

Gabriele Curci ◽

A. Rocha

Keyword(s):

Saharan Dust ◽

Vertical Resolution ◽

Dust Event

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April 2008 Saharan dust event: Its contribution to PM10 concentrations over the Anatolian Peninsula and relation with synoptic conditions

The Science of The Total Environment ◽

10.1016/j.scitotenv.2018.03.150 ◽

2018 ◽

Vol 633 ◽

pp. 317-328 ◽

Cited By ~ 10

Author(s):

B. Kabatas ◽

R.B. Pierce ◽

A. Unal ◽

M.J. Rogal ◽

A. Lenzen

Keyword(s):

Saharan Dust ◽

Dust Event ◽

Anatolian Peninsula ◽

Synoptic Conditions

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Spatial and Temporal Variation of the Extreme Saharan Dust Event over Turkey in March 2016

Atmosphere ◽

10.3390/atmos8020041 ◽

2017 ◽

Vol 8 (12) ◽

pp. 41 ◽

Cited By ~ 11

Author(s):

Hakki Baltaci

Keyword(s):

Temporal Variation ◽

Saharan Dust ◽

Spatial And Temporal Variation ◽

Dust Event

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Observations and model calculations of trace gas scavenging in a dense Saharan dust plume during MINATROC

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-655-2005 ◽

2005 ◽

Vol 5 (1) ◽

pp. 655-702

Author(s):

M. de Reus ◽

H. Fischer ◽

R. Sander ◽

V. Gros ◽

R. Kormann ◽

...

Keyword(s):

Accommodation Coefficient ◽

Heterogeneous Reactions ◽

Tropospheric Chemistry ◽

Saharan Dust ◽

Ozone Production ◽

Peroxy Radicals ◽

Dust Event ◽

Model Calculations ◽

Mixing Ratios ◽

Gas Scavenging

Abstract. An intensive field measurement campaign was performed in July/August 2002 at the Global Atmospheric Watch station Izaña on Tenerife to study the interaction of mineral dust aerosol and tropospheric chemistry (MINATROC). A dense Saharan dust plume, with aerosol masses exceeding 500 µg m-3, persisted for three days. During this dust event strongly reduced mixing ratios of ROx (HO2, CH3O2 and higher organic peroxy radicals), H2O2, NOx (NO and NO2) and O3 were observed. A chemistry boxmodel, constrained by the measurements, has been used to study gas phase and heterogeneous chemistry. It appeared to be difficult to reproduce the observed HCHO mixing ratios with the model, possibly related to the representation of precursor gas concentrations or the absence of dry deposition. The model calculations indicate that the reduced H2O2 mixing ratios in the dust plume can be explained by including the heterogeneous removal reaction of HO2 with an uptake coefficient of 0.2, or by assuming heterogeneous removal of H2O2 with an accommodation coefficient of 3×10-4. However, these heterogeneous reactions cannot explain the low ROx mixing ratios observed during the dust event. Whereas a mean daytime net ozone production rate (NOP) of 1.06 ppbv/hr occurred throughout the campaign, the reduced ROx and NOx mixing ratios in the Saharan dust plume contributed to a reduced NOP of 0.14–0.32 ppbv/hr, which likely explains the relatively low ozone mixing ratios observed during this event.

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Supplementary Materials (Distributions of Dissolved Manganese in the Surface Waters of the Tropical North-Eastern Atlantic Ocean)

Borneo Journal of Resource Science and Technology ◽

10.33736/bjrst.338.2016 ◽

2017 ◽

Vol 6 (2) ◽

pp. 1-10

Author(s):

Farah Akmal Idrus

Keyword(s):

Atlantic Ocean ◽

Euphotic Zone ◽

Saharan Dust ◽

Dust Event ◽

Atmospheric Flux ◽

Eastern Atlantic Ocean ◽

North Eastern ◽

Ocean Region ◽

Ne Atlantic Ocean ◽

Atmospheric Inputs

The tropical North-Eastern Atlantic (TNEA) Ocean region receives high atmospheric input every year, mostly from the Saharan dust and soil. This atmospheric dust and its deposition in the surface ocean are considered to be an important supply of nutrients and trace metal (e.g. dissolved manganese (DMn)) to the euphotic zone of the open ocean regions. Therefore, the objective of this study was to investigate the input of DMn from atmospheric sources and from nearby islands into the TNEA Ocean. A set of surface samples were collected from the Tropical NE Atlantic Ocean, and were analysed for DMn by using the flow injection analyser with chemiluminescence (FIA-CL). Results suggest the land-sources of DMn near to the Canary Islands, the Cape Verde Islands and the African Continent contributed the major inputs of DMn, where high DMn concentrations were determined, with the highest is 3.87±0.05 nM. The lateral advective flux of DMn was higher (47 μmol/m2/d) than the atmospheric flux of DMn (0.17 μmol/m2/d), thus making the shelf and sediment as the most prominent sources of DMn in the seawater close to the islands. From this atmospheric flux of DMn, it was then possible to estimate the DMn enrichment at further offshore dust event regions of 0.73 nM/yr and consistent with the DMn background concentrations. This support the low residence time calculated in dust event regions of around 1 year. In conclusion, the shelf and sediment are the most prominent DMn sources in the seawater close to the islands and mainland, while in further offshore, the atmospheric inputs are dominant.

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Extreme Saharan dust event over the southern Iberian Peninsula in september 2007: active and passive remote sensing from surface and satellite

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-9-15673-2009 ◽

2009 ◽

Vol 9 (4) ◽

pp. 15673-15723

Author(s):

J. L. Guerrero-Rascado ◽

F. J. Olmo ◽

I. Avilés-Rodríguez ◽

F. Navas-Guzmán ◽

D. Pérez-Ramírez ◽

...

Keyword(s):

Remote Sensing ◽

Iberian Peninsula ◽

Aerosol Optical Depth ◽

Optical Depth ◽

Saharan Dust ◽

Dust Event ◽

Passive Remote Sensing ◽

Angstrom Exponent ◽

Ångström Exponent ◽

Ångstrom Exponent

Abstract. This study investigates aerosol optical properties during the extreme Saharan dust event detected from 3 to 7 September 2007 over Granada, southern Iberian Peninsula, with both active and passive remote sensing instrumentation from surface and satellite. The intensity of the event was visualized on the aerosol optical depth series obtained by the sun-photometer Cimel CE 318-4 operated at Granada in the framework of AERONET from August 2004 until December 2008 (level 2 data). A combination of large aerosol optical depth (0.86–1.50) at 500 nm, and reduced Angström exponent (0.1–0.25) in the range 440–870 nm, was detected on 6 September during daytime. This Saharan dust event also affected other Iberian Peninsula stations included in AERONET (El Arenosillo and Évora stations). During the most intense stage, on 6 September, maximum aerosol backscatter values were a factor of 8 higher than other maxima during this Saharan dust event. Values up to 1.5×10−2 km−1 sr−1 at 355 and 532 nm were detected in the layer with the greatest aerosol load between 3–4 km a.s.l., although aerosol particles were also detected up to 5.5 km a.s.l. In this stage of the event, dust particles at these altitudes showed a backscatter-related Angström exponent between −0.44 and 0.53 for the two spectral intervals considered. The results from different measurements (active/passive and ground-based/satellite) reveal the importance of performing multi-instrumental measurements to properly characterize the contribution of different aerosol types from different sources during extreme events.

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