Abstract. Spectral measurements of the aerosol optical depth (AOD) and the Angstrom coefficient were conducted at Thessaloniki, Greece (40.5° N, 22.9° E) between January 1997 and December 2005 with a Brewer MKIII double-monochromator spectroradiometer. The dataset was compared with collocated measurements of a second spectroradiometer (Brewer MKII) and a CIMEL sun-photometer, showing correlations of 0.93 and 0.98 respectively. A seasonal variation of the AOD was observed at Thessaloniki, with AOD values at 340 nm of 0.52 and 0.28 for August and December respectively. Back trajectories of air masses for up to 4 days were used to assess the influence of long-range transport from various regions to the aerosol load over Thessaloniki. It is shown that part of the observed seasonality can be attributed to air masses with high AOD originating from North-Eastern and Eastern directions during summertime. The analysis of the long-term record (9 years) of AOD showed a downward tendency. A similar decreasing tendency was found in the record of the PM-10 aerosol measurements, which are conducted near the surface at 4 air-quality monitoring stations in the area of the city of Thessaloniki.

Abstract. Spectral measurements of the aerosol optical depth (AOD) and theÅngström coefficient were conducted at Thessaloniki, Greece (40.5 • N, 22.9 • E) between January 1997 and December 2005 with a Brewer MKIII doublemonochromator spectroradiometer. The dataset was compared with collocated measurements of a second spectroradiometer (Brewer MKII) and a CIMEL sun-photometer, showing correlations of 0.93 and 0.98, respectively. A seasonal variation of the AOD was observed at Thessaloniki, with AOD values at 340 nm of 0.52 and 0.28 for August and December respectively. Back trajectories of air masses for up to 4 days were used to assess the influence of long-range transport from various regions to the aerosol load over Thessaloniki. It is shown that part of the observed seasonality can be attributed to air masses with high AOD originating from North-Eastern and Eastern directions during summertime. The analysis of the long-term record (9 years) of AOD showed a downward tendency. A similar decreasing tendency was found in the record of the PM 10 aerosol measurements, which are conducted near the surface at 4 air-quality monitoring stations in the area of the city of Thessaloniki.

An experimental campaign was held at Thessaloniki, Greece (40.6°N, 22.9°E), in July 2006, in the framework of the integrated project Stratosphere‐Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere (SCOUT‐O3). One of the main objectives of the campaign was to determine the local aerosol properties and their impact on the UV irradiance at the Earth's surface. In this article, we present vertically resolved microphysical aerosol properties retrieved from the inversion of optical data that were obtained from a combined one‐wavelength Raman/two‐wavelength backscatter lidar system and a CIMEL Sun photometer. A number of assumptions were undertaken to overcome the limitations of the existing optical input data needed for the retrieval of microphysical properties. We found acceptable agreement with Aerosol Robotic Network retrievals for the fine‐mode particle effective radius, which ranged between 0.11 and 0.19 for the campaign period. It is shown that under complex layering of the aerosols, general assumptions may result in unrealistic retrievals, especially in the presence of aged smoke aerosols. Furthermore, with this instrument setup, the inversion algorithm can also be applied successfully for the complex refractive index in cases of vertically homogeneous layers of continental polluted aerosols. For these inversion cases, the vertically resolved retrievals for the single‐scattering albedo resulted in values around 0.9 at 532 nm, which were in very good agreement with estimates from airborne in situ observations obtained in the vicinity of the lidar site.

As the demand for the reduction of global emissions of carbon dioxide (CO2) increases, the need for anthropogenic CO2 emission reductions becomes urgent. One promising technology to this end, is carbon capture and storage (CCS). This paper aims to provide the current state-of-the-art of CO2 capure, transport, and storage and focuses on mineral carbonation, a novel method for safe and permanent CO2 sequestration which is based on the reaction of CO2 with calcium or magnesium oxides or hydroxides to form stable carbonate materials. Current commercial scale projects of CCS around Europe are outlined, demonstrating that only three of them are in operation, and twenty-one of them are in pilot phase, including the only one case of mineral carbonation in Europe the case of CarbFix in Iceland. This paper considers the necessity of CO2 sequestration in Greece as emissions of about 64.6 million tons of CO2 annually, originate from the lignite fired power plants. A real case study concerning the mineral storage of CO2 in Greece has been conducted, demonstrating the applicability of several geological forms around Greece for mineral carbonation. The study indicates that Mount Pindos ophiolite and Vourinos ophiolite complex could be a promising means of CO2 sequestration with mineral carbonation. Further studies are needed in order to confirm this aspect.

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