Eleni Marinou

Spatiotemporal variability and contribution of different aerosol types to the aerosol optical depth over the Eastern Mediterranean

This study characterizes the spatiotemporal variability and relative contribution of different types of aerosols to the Aerosol Optical Depth (AOD) over the Eastern Mediterranean as derived from MODIS Terra (3/2000-12/2012) and Aqua (7/2002-12/2012) satellite instruments. For this purpose, a 0.1° × 0.1° gridded MODIS dataset was compiled and validated against sunphotometric observations from the AErosol RObotic NETwork (AERONET). The high spatial resolution and long temporal coverage of the dataset allows for the determination of local hot spots like megacities, medium sized cities, industrial zones, and power plant complexes, seasonal variabilities, and decadal averages. The average AOD at 550 nm (AOD550) for the entire region is ~ 0.22 ± 0.19 with maximum values in summer and seasonal variabilities that can be attributed to precipitation, photochemical production of secondary organic aerosols, transport of pollution and smoke from biomass burning in Central and Eastern Europe, and transport of dust from the Sahara Desert and the Middle East. The MODIS data were analyzed together with data from other satellite sensors, reanalysis projects and a chemistry-aerosol-transport model using an optimized algorithm tailored for the region and capable of estimating the contribution of different aerosol types to the total AOD550. The spatial and temporal variability of anthropogenic, dust and fine mode natural aerosols over land and anthropogenic, dust and marine aerosols over the sea is examined. The relative contribution of the different aerosol types to the total AOD550 exhibits a low/high seasonal variability over land/sea areas, respectively. Overall, anthropogenic aerosols, dust and fine mode natural aerosols account for ~ 51 %, ~ 34 % and ~ 15 % of the total AOD550 over land, while, anthropogenic aerosols, dust and marine aerosols account ~ 40 %, ~ 34 % and ~ 26 % of the total AOD550 over the sea, based on MODIS Terra and Aqua observations.

A 3-D Evaluation of the MACC Reanalysis Dust Product Over Europe Using CALIOP/CALIPSO Satellite Observations

This work focuses on the evaluation of the MACC (Monitoring atmospheric composition and climate) reanalysis dust product over Europe. Europe receives significant amounts of dust on an annual basis primarily from the large neighboring area sources (Sahara Desert, Arabian Peninsula) and from smaller local sources. Dust affects a number of processes in the atmosphere modulating weather and climate and exerts an impact on human health and the economy. Hence, the ability of simulating adequately the amount of dust and its optical properties is essential. For the evaluation of the MACC reanalysis, pure dust satellite-based retrievals from CALIOP/CALIPSO are utilized for the period 2007–2012. Specifically, the CALIOP/CALIPSO data used here come from an optimized retrieval scheme that was originally developed within the framework of the LIVAS (Lidar Climatology of Vertical Aerosol Structure for Space-Based LIDAR Simulation Studies) project. The natural aerosol extinction coefficients from MACC and the dust optical depth patterns at 550 nm are validated against dust extinction coefficients and dust optical depth patterns at 532 nm from CALIOP/CALIPSO. Our results highlight the important role that space-based lidars may play in the improvement of the MACC aerosol product.

Evaluation of CALIPSO’s Aerosol Classification Scheme During the ACEMED Experimental Campaign Over Greece: The Case Study of 9th of September 2011

In order to assess the validity of CALIPSO’s aerosol classification scheme, an experimental campaign called ACEMED (Evaluation of CALIPSO’s aerosol classification scheme over Eastern Mediterranean) has been organized over Greece on September 2011. In this study, we concentrate on the characterization of the aerosol load over Greece on 9th of September, using advanced in-situ aircraft instrumentation (onboard the FAAM-Bae146 aircraft of the UK Met Office). The analytical evaluation of CALIPSO’s aerosol-type classification scheme that is performed using synchronous/collocated satellite/airborne measurements, show a qualitatively reasonable performance of the CALIPSO’s aerosol classification scheme in the complex aerosol environment of the case under study, where smoke, continental, urban and dust aerosol components are present.

Aerosol Vertical Profiling Utilizing the Synergy of Lidar, Sunphotometry and In-Situ Measurements in the Framework of the ACTRIS-2 Campaign in Athens

The importance of studying the aerosol vertical distribution is prominent in regional and climate studies. Aerosol profiling can contribute to the estimation of the cloud condensation nuclei (CCN) and ice nuclei (IN) concentrations, thus reducing the uncertainty in describing aerosol/cloud interactions. Aerosol absorption profiling contributes in defining the thermodynamic stability of the atmosphere while single scattering albedo profiling is crucial for radiative transfer calculations and climate modelling. The new Generalized Aerosol Retrieval from Radiometer and Lidar Combined data algorithm (GARRLiC) provides the opportunity to derive vertical profiles of aerosol microphysical properties combining active and passive ground-based remote sensing from lidar and sunphotometer measurements. GARRLiC has been developed in the frame of Aerosols, Clouds, and Trace gases Research InfraStructure Network (ACTRIS) to utilize the capabilities of combined European stations of the AErosol RObotic NETwork (AERONET) and the European Aerosol Research Lidar Network (EARLINET). Here, we utilize GARRLiC with measurements acquired during the Athens ACTRIS-2 campaign held during the winter months on 2016. The campaign focuses on the characterization of the alterations of the man-made aerosol pollution in the urban environment of Athens due to the economic crisis. Along with the remote sensing techniques, in situ measurements are performed providing absorption coefficients employing a micro-Aethalometer on board an Unmanned Aerial Vehicle (UAV). This detailed information is compared with GARRLiC profile products for an effective characterization of the aerosol properties along the atmospheric column.

Development of a Dust Assimilation System for NMM-DREAM Model Based on MSG-SEVIRI Satellite Observations

Initial and boundary conditions of dust are still a missing component in atmospheric modeling. In this context, dust models are usually initialized based on their own previous forecasting cycle. As it is obvious, even at the idealized hypothesis of a perfect model run, this approach implies the propagation of numerical diffusion errors. However, recent improvements in remote sensing retrievals of dust optical depth allow the timely generation of dust fields that can be used for assimilation in forecasting atmospheric modeling systems. In this work we present the methodology and preliminary results for the application of MSG/SEVIRI dust retrievals in the atmospheric model NMME-DREAM. First results of the assimilation method are compared with ground photometers (AERONET) and LIDAR (PollyXT) systems during Charadmexp campaign (15 June–15 July 2014). Significant improvement is found mainly over dust sources in Africa and Arabia deserts. The introduction of satellite assimilation methods in dust models provides an additional tool for the improvement of our understanding on the dust-atmosphere interactions and on their possible implications for climate change.