Satellite climatology of African dust transport in the Mediterranean atmosphere

Moulin, C.; Lambert, C. E.; Dayan, Uri; Masson, Valérie; Ramonet, Michel; Bousquet, Philippe; Legrand, Michel; Balkanski, Yves; Guelle, W.; Marticorena, Béatrice; Bergametti, Gilles; Dulac, François

doi:10.1029/98jd00171

Cited by 412 publications

(414 citation statements)

References 34 publications

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“…Milan presented high contributions during spring and summer, Porto during winter and Barcelona during the summer season. These results are in good agreement with Moulin et al (1998), who reported that the annual cycle of African dust transport over the Mediterranean region starts during springtime in the eastern part, while during summer there is maximum transport in the western part. Porto was the only city deviating from this behaviour, suggesting that the studied year may not be representative for this city for assessing seasonal trends, probably due to the low frequency and intensity of dust events.…”

Section: Contribution Of Natural Sources To Pm Concentrations and Excsupporting

confidence: 93%

AIRUSE-LIFE +: estimation of natural source contributions to urban ambient air PM10 and PM2. 5 concentrations in southern Europe – implications to compliance with limit values

et al. 2017

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Abstract. The contribution of natural sources to ambient air particulate matter (PM) concentrations is often not considered; however, it may be significant for certain areas and during specific periods of the year. In the framework of the AIRUSE-LIFE+ project, state-of-the-art methods have been employed for assessing the contribution of major natural sources (African dust, sea salt and forest fires) to PM concentrations, in southern European urban areas. 24 h measurements of PM 10 and PM 2.5 mass and chemical composition were performed over the course of a year in five cities: Porto, Barcelona, Milan, Florence and Athens. Net African dust and sea-salt concentrations were calculated based on the methodologies proposed by the EC (SEC 2011/208). The contribution of uncontrolled forest fires was calculated through receptor modelling. Sensitivity analysis with respect to the calculation of African dust was also performed, in order to identify major parameters affecting the estimated net dust concentrations. African dust contribution to PM concentrations was more pronounced in the eastern Mediterranean, with the mean annual relative contribution to PM 10 decreasing from 21 % in Athens, to 5 % in Florence, and around 2 % in Milan, Barcelona and Porto. The respective contribution to PM 2.5 was calculated equal to 14 % in Athens and from 1.3 to 2.4 % in all other cities. High seasonal variability of contributions was observed, with dust transport events occurring at different periods in the western and eastern Mediterranean basin. Sea salt was mostly related to the coarse mode and also exhibited significant seasonal variability. Sea-salt concentrations were highest in Porto, with average relative contributions equal to 12.3 % for PM 10 . Contributions from uncontrolled forest fires were quantified only for Porto and were low on an annual basis (1.4 and 1.9 % to PM 10 and PM 2.5 , respectively); nevertheless, contributions were greatly increased during events, reaching 20 and 22 % of 24 h PM 10 and PM 2.5 concentrations, respectively.

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Section: Contribution Of Natural Sources To Pm Concentrations and Excsupporting

confidence: 93%

AIRUSE-LIFE +: estimation of natural source contributions to urban ambient air PM10 and PM2. 5 concentrations in southern Europe – implications to compliance with limit values

et al. 2017

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“…When this happens, there is a corresponding induced flow of continental tropical air northwards, transporting dust with it (Dayan et al, 1991). The frequency of dust mobilization over North Africa and of dust intrusions over the Mediterranean Sea are, therefore, strongly related to the climatology of depressions affecting North Africa (Moulin et al, 1998). Katsnelson (1970) attributed dust events over Israel to thermal lows (including Sharav cyclones and Red Sea trough) and mentioned dynamic cold cyclones (Cyprus Lows) as a possible additional factor.…”

Section: Introductionmentioning

confidence: 99%

“…Ganor and Foner (2001) and Moulin et al (1998) showed that the mean annual TSP begins rising as early as January, which is the month in which Cyprus Lows are most frequent (Alpert et al, 1990), while other systems, regarded as producing dust, are less frequent. Both studies also mentioned the fact that dust is removed by precipitations, and therefore the residence time of particles in the atmosphere is much shorter when it rains, as is the case during the Cyprus Lows, and so reduces their signature as a major dust contributor.…”

Section: Introductionmentioning

confidence: 99%

“…Katsnelson (1970) attributed dust events over Israel to thermal lows (including Sharav cyclones and Red Sea trough) and mentioned dynamic cold cyclones (Cyprus Lows) as a possible additional factor. Moulin et al (1998), using METEOSAT imagery to explain the general pattern of the dust transport over the Mediterranean basin (MB), stated that in its eastern part most of the dust transport occurs between January and July. They found that the pulsative nature of dust intrusions into the region indicate that they originate from transient disturbances, i.e.…”

Section: Introductionmentioning

confidence: 99%

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Suspended dust over southeastern Mediterranean and its relation to atmospheric circulations

Dayan

Ziv

Shoob

et al. 2007

Intl Journal of Climatology

143

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ABSTRACT:The Middle East deserts are often subjected to dust, which reduces horizontal visibility to 5 km, and sometimes even to <1 km. The present study examines the annual and inter-annual occurrences of dust events based on 37 years of visibility observations from Hazerim (near Beer Sheba) correlated with PM 10 dust concentration. The visibility data was converted to PM 10 dust concentration, using concurrent data for three years. We then analyse the linkage between dust and synoptic-to global-scale weather systems.The monthly data indicate that the dust season starts in October and ends in May, with a maximum in March. More than 89% of the total annual dust is accumulated between December and May, the 'high dust season'. The annual totals vary as much as an order of magnitude from year to year.The synoptic system that produces the majority of the dust over the northern Negev is the Cyprus Low, contributing 2/3 of both the total yearly dust yield and of the number of dust observations. This suggests that a positive relationship exists between the dust in the Negev and rainfall in north Israel, both of which are generated by Cyprus Lows. Indeed, a significant (at 0.05 level) correlation of +0.30 was found between the two. Correlation maps evidence that in dustrich years the cyclonic activity over the Mediterranean is abnormally high and in poor-dust years it is low. A highly significant negative correlation (−0.66) was found between the dust yield and the intensity of the North Atlantic oscillation (NAO), which modulates the cyclonic activity over Europe and the northern Mediterranean. This may also imply that periods in which more dust accumulated as loess in the northern Negev may indicate the existence of negative NAO phase, and concurrently, warmer conditions over the Sahara, colder conditions over Europe and enhanced rainfall over the Mediterranean Basin.

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“…The Sahara and its borders constitute the main source of mineral dust, yielding over 50% of the global production. The Saharan dust transport is a significant climatic process (Tanré and Legrand, 1991), primarily westwards, across the Atlantic Ocean (D'Almeida, 1986;Prospero and Lamb, 2003;Petit et al, 2005), but also northwards (Moulin et al, 1998). Mineral dust absorbs and scatters the shortwave and longwave radiations, as well as it emits longwave radiation.…”

Section: Introductionmentioning

confidence: 99%

Improvement of the detection of desert dust over the Sahel using METEOSAT IR imagery

et al. 2006

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Abstract.Desert dust over the arid regions of Africa is detected using the Infrared Difference Dust Index (IDDI) derived from the thermal infrared (TIR) channel of METEOSAT. However, the comparison with photometric aerosol optical thickness (AOT) of this dust index reveals some discrepancies. Using an instrumented site in Sahel where aerosol properties and meteorological conditions were monitored daily during the dry season, we performed radiative transfer computations with the MODTRAN 4.1 code to develop a method to improve the IDDI usefulness. We found that discrepancies between AOT and IDDI variations mostly come from changes in the surface temperature (T s ), which is an important parameter for radiative transfer computations in the TIR. We show that this temperature varies from day to day with the surface wind speed and during the course of the season with the solar elevation, and that it is possible, for the site considered, to correct T s from these combined effect using a simple parameterization. We also observe that the dust layer itself has an impact on T s by reducing the amount of solar radiation at the surface, and that this phenomenon can also be accounted for by adding an AOT-dependence to the above parameterization of T s . We show that this parameterization allows improving the agreement between the IDDI and the photometric AOT.

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Satellite climatology of African dust transport in the Mediterranean atmosphere

Cited by 412 publications

References 34 publications

AIRUSE-LIFE +: estimation of natural source contributions to urban ambient air PM<sub>10</sub> and PM<sub>2. 5</sub> concentrations in southern Europe – implications to compliance with limit values

AIRUSE-LIFE +: estimation of natural source contributions to urban ambient air PM<sub>10</sub> and PM<sub>2. 5</sub> concentrations in southern Europe – implications to compliance with limit values

Suspended dust over southeastern Mediterranean and its relation to atmospheric circulations

Improvement of the detection of desert dust over the Sahel using METEOSAT IR imagery

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Satellite climatology of African dust transport in the Mediterranean atmosphere

Cited by 412 publications

References 34 publications

AIRUSE-LIFE +: estimation of natural source contributions to urban ambient air PM&lt;sub&gt;10&lt;/sub&gt; and PM&lt;sub&gt;2. 5&lt;/sub&gt; concentrations in southern Europe – implications to compliance with limit values

AIRUSE-LIFE +: estimation of natural source contributions to urban ambient air PM&lt;sub&gt;10&lt;/sub&gt; and PM&lt;sub&gt;2. 5&lt;/sub&gt; concentrations in southern Europe – implications to compliance with limit values

Suspended dust over southeastern Mediterranean and its relation to atmospheric circulations

Improvement of the detection of desert dust over the Sahel using METEOSAT IR imagery

Contact Info

Product

Resources

About

AIRUSE-LIFE +: estimation of natural source contributions to urban ambient air PM<sub>10</sub> and PM<sub>2. 5</sub> concentrations in southern Europe – implications to compliance with limit values

AIRUSE-LIFE +: estimation of natural source contributions to urban ambient air PM<sub>10</sub> and PM<sub>2. 5</sub> concentrations in southern Europe – implications to compliance with limit values