Measurements of desert dust optical characteristics at Porte au Sahara during SAMUM

Hoyningen‐Huene, W. von; Dinter, T.; Kokhanovsky, A.; Burrows, J. P.; Wendisch, M.; Bierwirth, E.; Müller, Detlef; Diouri, Mohammed

doi:10.3402/tellusb.v61i1.16824

Cited by 16 publications

(20 citation statements)

References 12 publications

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“…The type of aerosol changes alternately because of the weak influence associated with Atlantic air masses that moderate the original air masses of dust load coming from East and Sahara in summer. During the experimental measurement campaign SAMUM conducted in May-June 2006 in Ouarzazate, the daily average of the EOA at 0.5μm is 0.28 [10], in agreement with the AERONET data (Table 3). At Saada, a maximum peak is observed in summer 2013 (~ 0.26) corresponding to mixtures of atmospheric aerosol transported loads from desert Southeast Morocco and, to urban pollution and industrial facing the city of Marrakech especially in summer.…”

Section: Aerosol Optical Depth and Angstrom Coefficientsupporting

confidence: 82%

“…This territory is the primary source of aerosol emission almost ubiquitous in the Moroccan atmosphere. Since 1997 several studies of the Moroccan desert aerosol were performed including two measurement campaigns: Oujda in summer 1997 [2] [3] [4] [5] [7] [9] and Ouarzazate and Tinfou (Zagora) in May-June 2006 [1] that allowed the wide determination of the physic-chemical characteristics of the emitted particles [13] and their dynamics and radiative properties [10]. Oujda campaign showed that the frequency of desert storms is very low with appearances in spring and especially in summer.…”

Section: Introductionmentioning

confidence: 99%

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Desert aerosol optical properties in Morocco

Tahiri¹,

Diouri²,

Steli³

et al. 2016

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Moroccan weather and climate are influenced by desert winds coming from South-East and by Atlantic advections. The annual cycle of seasonal average of aerosol optical depht shows similar values in Oujda and Saada and registers higher values in Ouarzazate, due to different weather conditions. The maximum values are recorded in summer near 0.25 (Oujda, Saada) and 0.34 (Ouarzazate). The seasonal average of the refraction index varies with the seasons, the component relating to scattering at 0.44 microns varies lightly in summer (1.48 -1.51) and the component relating to absorption varies (6.65×10 -3 -13.13×10 -3 ) with more higher values in Oujda. The single scattering albedo is almost constant for every season and indicates a very important trend in the diffusion which often exceeds 89% in summer. The asymmetry factors seem constant close 0.73 in summer indicating more forward scatter. The volume distributions show a mode of very fine particles around 0.015 μm and a much more important mode of large particles around 2.6 μm (annual average) that registers large amplitudes in spring and especially in summer (seasons penetration of desert dust across all regions by the advection of air masses mainly from Southeast Morocco). The annual average radiative forcing are relatively stable around -25.34 W/m 2 to bottom and -4 W/m 2 at the top of the atmosphere.

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Section: Aerosol Optical Depth and Angstrom Coefficientsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Desert aerosol optical properties in Morocco

Tahiri¹,

Diouri²,

Steli³

et al. 2016

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“…The differences encountered among the retrievals of simultaneous almucantar observations with different codes where also reported by von Hoyningen‐Huene et al (2009) for the SAMUM‐1 data. This disparity motivated us to validate the Sun‐sky radiometer retrievals with other data, especially in situ, as was done for SAMUM‐1 data (Müller et al, 2010a,b).…”

Section: Resultsmentioning

confidence: 65%

“…The Sun photometer observations during SAMUM‐1 showed a predominance of aerosols characterized by the optical properties of pure dust (Toledano et al, 2009; von Hoyningen‐Huene et al, 2009). A comparison of AERONET inversion products with in situ measurements of dust optical and microphysical properties was also carried out during this experiment (Müller et al, 2010a,b).…”

Section: Introductionmentioning

confidence: 99%

Optical properties of aerosol mixtures derived from sun-sky radiometry during SAMUM-2

Toledano

Wiegner

Groß

et al. 2011

Tellus B: Chemical and Physical Meteorology

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This journal is published under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported LicenseThe SAMUM-2 experiment took place in the Cape Verde islands in January-February 2008. The colocated ground-based and airborne instruments allow the study of desert dust optical and microphysical properties in a closure experiment. The Meteorological Institute of the University of Munich deployed one sun-sky photometer and two tropospheric lidar systems. A travelling AERONET-Cimel sun-sky radiometer was also deployed. During the measurement period the aerosol scenario over Cape Verde mostly consisted of a dust layer below 2 km and a smoke-dust layer above 2-4 km a.s.l. The Saharan dust arrived at the site from the NE, whereas the smoke originated in the African equatorial region. This paper describes the main results of the Sun photometer observations, supported by lidar information. An analysis of the variations in the aerosol optical depth (AOD) in the range 340-1550 nm, the Angstrom exponent, volume size distributions and single scattering albedo is presented. The aerosol mixtures are analysed by means of the fine mode fraction of the AOD provided by the sun-sky inversion data and the Spectral Deconvolution Algorithm. The mean AOD (500 nm) was 0.31, with associated low Angstrom exponent of 0.46. Several types of events were detected within the data set, with prevalence of dust or mixtures as characterized by the Angstrom exponents of extinction and absorption and the fine mode fraction. Aerosol properties derived from sunphotometry were compared to in situ measurements of size distribution, effective radius and single scattering albedo

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“…The highlights of the lidar activities and the main findings are presented in Table 4. The lidar products and the SAMUM photometer results of Toledano et al (2009, 2011) and von Hoyningen‐Huene et al (2009) were used in a variety of SAMUM closure and transport modelling studies and verification of passive remote sensing from space (Dinter et al, 2009; Kahn et al, 2009). They served as benchmark data in tests of scattering models for non‐spherical dust particles and in CALIPSO ground truth activities, and triggered the development of new lidar‐based schemes for the separation of the optical properties of dust and non‐dust (i.e.…”

Section: Samum–1 and Samum–2 Highlights And Main Findings: What Hamentioning

confidence: 99%

Saharan Mineral Dust Experiments SAMUM–1 and SAMUM–2: what have we learned?

Ansmann¹,

Petzold²,

Kandler

et al. 2011

Tellus B: Chemical and Physical Meteorology

237

155

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A B S T R A C T Two comprehensive field campaigns were conducted in 2006 and 2008 in the framework of the Saharan Mineral Dust Experiment (SAMUM) project. The relationship between chemical composition, shape morphology, size distribution and optical effects of the dust particles was investigated. The impact of Saharan dust on radiative transfer and the feedback of radiative effects upon dust emission and aerosol transport were studied. Field observations (ground-based, airborne and remote sensing) and modelling results were compared within a variety of dust closure experiments with a strong focus on vertical profiling. For the first time, multiwavelength Raman/polarization lidars and an airborne high spectral resolution lidar were involved in major dust field campaigns and provided profiles of the volume extinction coefficient of the particles at ambient conditions (for the full dust size distribution), of particle-shape-sensitive optical properties at several wavelengths, and a clear separation of dust and smoke profiles allowing for an estimation of the single-scattering albedo of the biomass-burning aerosol. SAMUM-1 took place in southern Morocco close to the Saharan desert in the summer of 2006, whereas SAMUM-2 was conducted in Cape Verde in the outflow region of desert dust and biomass-burning smoke from western Africa in the winter of 2008. This paper gives an overview of the SAMUM concept, strategy and goals, provides snapshots (highlights) of SAMUM-2 observations and modelling efforts, summarizes main findings of SAMUM-1 and SAMUM-2 and finally presents a list of remaining problems and unsolved questions.

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Measurements of desert dust optical characteristics at Porte au Sahara during SAMUM

Cited by 16 publications

References 12 publications

Desert aerosol optical properties in Morocco

Desert aerosol optical properties in Morocco

Optical properties of aerosol mixtures derived from sun-sky radiometry during SAMUM-2

Saharan Mineral Dust Experiments SAMUM–1 and SAMUM–2: what have we learned?

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