Aerosol Distributions and Transport over Southern Morocco from Ground-Based and Satellite Observations (2004–2020)

Millet, Tristan; Benchérif, Hassan; Bounhir, Aziza; Bègue, Nelson; Lamy, Kévin; Ranaivombola, Marion; Benkhaldoun, Z.; Portafaix, Thierry; Duflot, Valentin

doi:10.3390/atmos13060923

Cited by 7 publications

(6 citation statements)

References 44 publications

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“…However, MERRA-2 seems to be in better agreement with the ground-based AERONET observations. These results are consistent with the finding reported by Millet et al [52] in their comparative study for the same region. To determine the type of aerosols during the event, the daily VSD derived from AERONET observations at Saada between 1 and 5 of August were superimposed on Figure 5b.…”

Section: Aeronet Ground-based Datasupporting

confidence: 94%

Aerosol Distributions and Sahara Dust Transport in Southern Morocco, from Ground-Based and Satellite Observations

et al. 2022

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The present study investigates aerosols distributions and a strong Sahara dust-storm event that occurred by early August 2018, in the South of Morocco. We used columnar aerosol optical depth (AOD), Angstrom Exponent (AE) and volume size distributions (VSD) as derived from ground-based observations by 2 AERONET (AErosol RObotic NETwork) sun-photometers at Saada (31.63°N, 8.16°W) and Ouarzazate (30.93°N, 6.91°W) sites, over the periods 2004–2019 and 2012–2015, respectively. The monthly seasonal distributions of AOD, AE, and VSD showed a seasonal trend dominated by the annual cycle, with a maximum aerosol load during summer (July–August) and a minimum in winter (December–January), characterized by a coarse mode near the radius of 2.59 μm and a fine mode at the radius of 0.16 μm, respectively. Indeed, this study showed that aerosol populations in southern Morocco are dominated by Saharan desert dust, especially during the summer season. The latter can sometimes be subject of dust-storm events. The case study presented in this paper reports on one of these events, which happened in early August 2018. The HYSPLIT (HYbrid Single Particle Lagrangian Integrated Trajectory) model was used to simulate air-mass back-trajectories during the event. In agreement with ground-based (AERONET sun-photometers) and satellite (CALIOP, MODIS and AIRS) observations, HYSPLIT back-trajectories showed that the dust air-mass at the 4-km layer, the average height of the dust plume, has crossed southern Morocco over the Saada site, with a westward direction towards the Atlantic Ocean, before it changed northward up to the Portuguese coasts.

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Section: Aeronet Ground-based Datasupporting

confidence: 94%

Aerosol Distributions and Sahara Dust Transport in Southern Morocco, from Ground-Based and Satellite Observations

et al. 2022

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“…We clustered the trajectories using TrajStat, an algorithm developed by Wang et al [54] as a GIS-based program to view, query, and group the trajectories. This program had already been used in the study of Millet et al [55] in the identification and analysis of the observed seasonal aerosol variations over Southern Morocco. The number of clusters can be visually determined by inspecting the total spatial variation (TSV) curve before a net increase in TSV (see Figure A2, in Appendix A).…”

Section: Hysplit Back-trajectoriesmentioning

confidence: 99%

Aerosol Optical Properties and Types over Southern Africa and Reunion Island Determined from Ground-Based and Satellite Observations over a 13-Year Period (2008–2021)

et al. 2023

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Fires occur seasonally in Southern Africa, from June to November, increasing tropospheric aerosol loading and triggering harmful consequences for the environment and human health. This study aims to examine 13 years of aerosol optical characteristics and types over Southern Africa and Reunion Island. Using AERONET sun photometers and MODIS observations, we found that a high aerosol optical depth and Angström exponent are associated with two predominant types of aerosols (biomass burning/urban industrial and mixed type) throughout the spring season. According to CALIOP observations, the major aerosol types with occurrence frequencies above 10% are polluted continental/smoke, polluted dust, and elevated smoke, whereas dust, clean continental, and dusty marine have occurrence frequencies below 1%. In comparison to other seasons, the vertical profiles of elevated smoke have different shapes in spring, with a seasonal shift in the peak altitude (from 3–4 km), when fire activity is at its maximum. At these altitudes, the northern regions presented occurrence frequencies of 32% on average, while lower values were found for the southern or farthest regions (<10–20% on average). The Lagrangian HYSPLIT model back-trajectories demonstrated eastward transport, with air masses from South America and the Atlantic Ocean that recirculate around the study sites. The aerosols are mainly derived from active biomass burning areas near the study sites and, to a lesser extent, from remote sources such as South America.

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“…These datasets have provided data on the characteristics of cloud, various aerosol, and other atmospheric products since 1979. The aerosol products of MERRA-2 are obtained by the assimilation of data from AErosol RObotic NETwork (AERONET) stations, Moderate Resolution Imaging Spectroradiometer MODIS), and many other station data [29]. MERRA-2 datasets include global observable parameters and aerosol diagnostics with different times (1 month, 3 h, and 1 h) at spatial resolutions (0.5 • × 0.625 • ).…”

Section: Modern-era Retrospective Analysis For Research and Applicati...mentioning

confidence: 99%

Exploring the Spatiotemporal Variation in Light-Absorbing Aerosols and Its Relationship with Meteorology over the Hindukush–Himalaya–Karakoram Region

et al. 2023

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Light-absorbing aerosols such as black carbon (BC), organic carbon (OC), and dust can cause the warming and melting of glaciers by absorbing sunlight. Further research is needed to understand the impact of light-absorbing aerosols on the Hindukush–Karakoram–Himalaya region in northern Pakistan. Therefore, spatiotemporal variation in absorbing surface mass concentration retrieved from Modern-Era Retrospective analysis for Research and Applications, optical properties such as aerosol optical depth (AOD) and absorption aerosol optical depth (AAOD) from the ozone monitoring instrument, and meteorological parameters from the European Centre for Medium-Range Weather Forecasts Reanalysis were investigated over northern Pakistan from 2001 to 2021. The BC concentration was lowest in May and highest in November, having a seasonal maximum peak in winter (0.31 ± 0.04 µg/m3) and minimum peak in spring (0.17 ± 0.01 µg/m3). In addition, OC concentration was found to be greater in November and smaller in April, with a seasonal higher peak in autumn (1.32 ± 0.32 µg/m3) and a lower peak in spring (0.73 ± 0.08 µg/m3). The monthly and seasonal variabilities in BC and OC concentrations are attributed to solid fuels, biomass burning, changes in vegetation, agricultural activities, and meteorology. In contrast, the dust concentration was high in July and low in December, with a seasonal average high concentration in summer (44 ± 9 µg/m3) and low concentration in winter (13 ± 2 µg/m3) due to drier conditions, dust activity, long-range transport, and human activities. Moreover, the seasonal variation in AOD and AAOD was identical and higher in the summer and lower in the winter due to dust aerosol loading and frequent dust activities. AOD and AAOD followed a similar pattern of spatial variation over the study area. Meteorological parameters greatly impact light-absorbing aerosols; therefore, low temperatures in winter increase BC and OC concentrations due to shallow boundary layers, while severe precipitation in spring decreases concentrations. During summer, dry conditions cause soil erosion and increase the amount of dust suspended in the atmosphere, leading to higher AOD and AAOD values. Conversely, higher precipitation rates and speedy winds disperse the dust aerosols in winter, resulting in lower AOD and AAOD values.

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Aerosol Distributions and Transport over Southern Morocco from Ground-Based and Satellite Observations (2004–2020)

Cited by 7 publications

References 44 publications

Aerosol Distributions and Sahara Dust Transport in Southern Morocco, from Ground-Based and Satellite Observations

Aerosol Distributions and Sahara Dust Transport in Southern Morocco, from Ground-Based and Satellite Observations

Aerosol Optical Properties and Types over Southern Africa and Reunion Island Determined from Ground-Based and Satellite Observations over a 13-Year Period (2008–2021)

Exploring the Spatiotemporal Variation in Light-Absorbing Aerosols and Its Relationship with Meteorology over the Hindukush–Himalaya–Karakoram Region

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