Investigation of an Intense Dust Outbreak in the Mediterranean Using XMed-Dry Network, Multiplatform Observations, and Numerical Modeling

Abstract

The Weather Research and Forecasting (WRF) model with online coupled chemistry (WRF-Chem) is applied to study an intense Saharan dust outbreak event affecting the Italian peninsula in 15 and 16 April, 2018. According to the MODIS retrievals, this intrusion was characterized by an intense aerosol optical depth (AOD) peak value in the southern Mediterranean. Measurements within the Dry Deposition Network Across the Mediterranean (XMed-Dry) are compared with the output of the WRF-Chem model. XMed-Dry samples from Lecce (Italy), Athens (Greece) and San Lawrenz/Gozo (Malta) were analysed with respect to aerosol particle size distribution, relative dust contribution, and composition. The discrepancy between the model and measured deposition indicate the need to formulate in WRF-Chem more sophisticated deposition schemes, this will need to evaluate the sensitivity of the results to the precise particle size limits chosen for the aerosol model. Moreover, satellite retrievals from MODIS sensors elaborated with the MAIAC algorithm, Aeronet stations, and measurements of at the selected sites were also considered. In a numerical domain that spans the Mediterranean and the northern Saharan desert, two different dust emission schemes, namely Gocart-AFWA and the Shao-2001, were tested and compared with multiplatform observations for simulation period covering the dust outbreak. Actual results indicate that both emission schemes would benefit from replacing the static erodibility map and soil particle distribution with remote sensed and in-situ observational data.

A review of coarse mineral dust in the Earth system

“…The collection of actual aeolian dust for the study of its physical properties and mineralogical-and chemical composition in relation to atmospheric-transported processes was probably described first in Barbados, and many dust-deposition stations have been set up thereafter, such as in French Guyana (Prospero et al, 1981), Mali (Kaly et al, 2015), Senegal (Skonieczny et al, 2013), Tenerife (Prospero, 1996), Gran Canaria (Torres-Padrón et al, 2002), Crete (Guerzoni and Chester, 1996). In addition, larger programs were set up to monitor dust across regions in southeast Australia (Leys et al, 2008), the central north Atlantic Ocean (Korte et al, 2017), and the Mediterranean (XMed-Dry) (Rizza et al, 2021).…”

A review of coarse mineral dust in the Earth system

“…The collection of actual aeolian dust for the study of its physical properties and mineralogical-and chemical composition in relation to atmospheric-transported processes was probably described first in Barbados, and many dust-deposition stations have been set up thereafter, such as in French Guyana (Prospero et al, 1981), Mali (Kaly et al, 2015), Senegal (Skonieczny et al, 2013), Tenerife (Prospero, 1996), Gran Canaria (Torres-Padrón et al, 2002), Crete (Guerzoni and Chester, 1996). In addition, larger programs were set up to monitor dust across regions in southeast Australia (Leys et al, 2008), the central north Atlantic Ocean (Korte et al, 2017), and the Mediterranean (XMed-Dry) (Rizza et al, 2021).…”

Effect of Aerosol Vertical Distribution on the Modeling of Solar Radiation

“…RT simulations were performed assuming typical optical properties for dust-dominated aerosol mixtures (AE = 0.3 and SSA: 0.8, 0.85, 0.95, 0.98 for UVB, UVA, VIS, and NIR, respectively) [17,76] and 550 nm AOD = 1. Extreme dust events where AOD at 550 nm exceeds 1 have been recorded over the Mediterranean Basin (e.g., [77]), but are very rare, while events with AOD of 0.8-1 are more frequent. Thus, AOD = 1 was chosen in order to study the effect of the aerosol extinction profile during strong dust events.…”