Modelling Saharan dust transport into the Mediterranean basin with CMAQ

Abstract

HIGHLIGHTS• A dust emission module has been implemented in the WRF-SMOKE-CMAQ modelling system.• The system has been applied and evaluated for Saharan dust outbreaks into Europe.• Contributions up to 14 ng rrT 3 to 24-h PMio concentration were predicted in Spain.• Global R-value for ground-level PMio increased from 0.33 to 0.48.• Good agreement with satellite products although AOD is underestimated. ABSTRACTThe need for a better quantification of the influence of Saharan dust transport processes on the air quality modelling in the Mediterranean basin led to the formulation of a dust emission module (DEM) integrated into the Air Quality Risk Assessment System for the Iberian Peninsula (SERCA). This paper is focused on the formulation of DEM based on the GOCART aerosol model, along with its integration and execution into the air quality model. It also addresses the testing of the module and its evaluation by contrasting results against satellite products such as MODIS and CALIPSO and ground-level observations of aerosol optical thickness (AOT) and concentration levels of PMio for different periods in July 2007. DEM was found capable of reproducing the spatial (horizontal and vertical) and temporal profiles of Saharan dust outbreaks into the Mediterranean basin and the Atlantic coast of Africa. Moreover, it was observed that its combination with CMAQ increased the correlation degree between observed and modelled PMio concentrations at the selected monitoring locations. DEM also enhanced CMAQ capabilities to reproduce observed AOT, although significant underestimations remain. The implementation of CMAQ + DEM succeeded in capturing Saharan dust transport into the Iberian Peninsula, with contributions up to 25 and 14 ng rrT 3 in 1 h and 24 h average PMio respectively. The general improvement of total PMio predictions in Spain are however moderate. The analysis of model performance for the main PM components points out that remaining PMio underestimation is due to dust local sources missing in the inventories and misrepresentation of organic aerosol processes, which constitutes the main areas for future improvement of CMAQ capabilities to simulate particulate matter within SERCA.

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

“…Information about the vertical structure of the dust episode and vertical behaviors of the atmospheric conditions is provided from attenuated backscatter profiles at 532 nm retrieved from the spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the CALIPSO together with its 60 m and 12 km vertical and horizontal resolutions, respectively. From the literature, numerous studies investigated the vertical structure of the Saharan dust outbreaks by using CALIPSO observations for Mediterranean Basin (e.g., [24][25][26]) and for Turkey [21]. In this study, CALIPSO observations for 23 March.…”

Ozone and aerosol tropospheric concentrations variability analyzed using the ADRIMED measurements and the WRF and CHIMERE models

“…During the MINOS campaign (Mediterranean Intensive Oxidant Study; Lelieveld et al, 2002) over the same region, Roelofs et al (2003) reported ozone concentrations in altitude of about 50 ppb, with peaks reaching 120 ppb. Lidar observations of ozone undertaken during the ESCOMPTE campaign (Expérience sur site pour contraindre les modèles de pollution atmosphérique et de transport d'émissions; Cros et al, 2004), in summer in the western part of the Mediterranean showed that highly concentrated plumes may be formed over a given country and transported for several hundreds of kilometers, before reaching ground levels (Colette et al, 2006). Aerosols are also highly variable in space, time and composition.…”

“…For example, ozone was simulated using the CHIMERE regional CTM during the ESCOMPTE campaign (Menut et al, 2005) and the summertime ozone maximum was analyzed using the TOMCAT global CTM (Richards et al, 2013). Aerosol observations in the Mediterranean area often show large contributions from mineral dust, so that numerous studies were devoted to this species (Pérez et al, 2011;Nabat et al, 2012;Menut et al, 2013b;de la Paz et al, 2013). Their impact on climate via their radiative effect was recently analyzed with the models COSMO (Vogel et al, 2009), RegCM (Santese et al, 2010), SKYRON (Spyrou et al, 2013) and ALADIN-Climate .…”

“…Many experimental research programs were recently conducted to characterize the aerosol properties using surface measurements (Querol et al, 2009), airborne measurements (Dulac and Chazette, 2003), optical depths measured by sunphotometers (Kubilay et al, 2003), lidar measurements including EARLINET (European Aerosol Research LIdar Network to Establish an Aerosol Climatology; Papayannis et al, 2008;Pappalardo et al, 2014) or satellite data (Barnaba and Gobbi, 2004). Remotely sensed surface measurements are also used to better quantify the dust optical properties and direct radiative forcing as in Bergamo et al (2008), Basart et al (2009), Mallet et al (2013), and di Sarra et al (2008). The integrated project EUCAARI (dedicated to the Aerosol Climate Air Quality Interactions; Kulmala et al, 2011) was conducted to better characterize the aerosol life cycle and composition in Europe, integrating many types of aerosol studies, from the nano to the global scales, with a large scientific community.…”

An estimated method of urban PM2.5 concentration distribution for a mobile sensing system

“…WRF-CMAQ has significant improvements especially for suspended particulate matter. D. Paz et al [24] combine dust emission module (DEM) with CMAQ and implements WRF-SMOKE-SMAQ system to increase the correlation degree between observed and modeled PM 10 concentrations. Han et al [25] obtain an in-depth understanding of the relationship between regional low visibility and aerosol particles based on Regional Atmospheric Modeling System (RAMS)-CMAQ.…”