The MACC-II 2007–2008 reanalysis: atmospheric dust evaluation and characterization over northern Africa and the Middle East

Abstract

Abstract. In the present work, atmospheric mineral dust from a MACC-II short reanalysis run for 2 years (2007–2008) has been evaluated over northern Africa and the Middle East using satellite aerosol products (from MISR, MODIS and OMI satellite sensors), ground-based AERONET data, in situ PM10 concentrations from AMMA, and extinction vertical profiles from two ground-based lidars and CALIOP satellite-based lidar. The MACC-II aerosol optical depth (AOD) spatial and temporal (seasonal and interannual) variability shows good agreement with those provided by satellite sensors. The capability of the model to reproduce the AOD, Ångström exponent (AE) and dust optical depth (DOD) from daily to seasonal time-scale is quantified over 26 AERONET stations located in eight geographically distinct regions by using statistical parameters. Overall DOD seasonal variation is fairly well simulated by MACC-II in all regions, although the correlation is significantly higher in dust transport regions than in dust source regions. The ability of MACC-II in reproducing dust vertical profiles has been assessed by comparing seasonal averaged extinction vertical profiles simulated by MACC-II under dust conditions with corresponding extinction profiles obtained with lidar instruments at M'Bour and Santa Cruz de Tenerife, and with CALIOP. We find a good agreement in dust layers structures and averaged extinction vertical profiles between MACC-II, the lidars and CALIOP above the marine boundary layer from 1 to 6 km. Surface dust daily mean concentrations from MACC-II reanalysis has been evaluated with daily averaged PM10 at three monitoring stations of the Sahelian Dust Transect. MACC-II correctly reproduces daily to interannual surface dust concentration variability, although it underestimates daily and monthly means all year long, especially in winter and early spring (dry season). MACC-II reproduces well the dust variability recorded along the station transect which reflects the variability in dust emission by different Saharan sources, but fails in reproducing the sporadic and very strong dust events associated to mesoscale convective systems during the wet season.

Saharan dust long-range transport across the Atlantic studied by an airborne Doppler wind lidar and the MACC model

“…These values are similar to those presented in Groß et al (2016), where the average lidar ratio observed in the ABL was 26 ± 5 sr, with values ranging from 22 ± 5 sr in the case of pure marine aerosol to 35 ± 3 sr for the case of a dust-dominated ABL. These results, corresponding to June-July 2013, are in agreement with the CALIOP retrievals presented in Cuevas et al (2015), where a similar difference in the ABL extinction in the west African region (M'Bour) was also observed during the summer seasons of 2007 and 2008.…”

“…A detailed description of the model and parameterizations is given in Morcrette et al (2009), while the assimilation process is explained in Benedetti et al (2009) and a companion paper by Mangold et al (2011) provides a first validation of the model results. Additional validation of the aerosol MACC products in northern Africa and the Middle East can be found in the work by Cuevas et al (2015).…”

Aerosol optical depth retrievals at the Izaña Atmospheric Observatory from 1941 to 2013 by using artificial neural networks

“…The typical background free troposphere conditions at IZO are only significantly modified in summer, mainly in July and August, when the most intense and relatively frequent Saharan air mass outbreaks in the subtropical free troposphere reach the observatory (Cuevas, 1996;Rodríguez et al, 2011;Cuevas et al, 2013Cuevas et al, , 2015bBarreto et al, 2014;Rodríguez et al, 2015). During these months, Saharan dust long-range transport over the Atlantic that can reach the Caribbean is driven by incursions of the so-called Saharan air layer (SAL) over the North Atlantic (Prospero et al, 2002, and references therein).…”

Validation of reactive gases and aerosols in the MACC global analysis and forecast system

“…More detailed validation results have been (and will be) described in several scientific papers from the individual partners of VAL Cuevas et al, 2015;Wagner et al, 2015;Langerock et al, 2015;Katragkou et al, 2015) or contributions to papers led by partners from other sub-projects of MACC Flemming et al, 2015;Pérez García-Pando et al, 2014;Stein et al, 2014;Cesnulyte et al, 2014). Several of these papers are submitted to the MACC special issue of the EGU Copernicus journals Atmospheric Chemistry and …”