Remote sensing aerosol observations from AREAD ship campaign in the Mediterranean and Middle East

Atmospheric Research Expedition to Abu Dhabi (AREAD) is a ship campaign that sailed from Vigo, Spain to Abu Dhabi, UAE between 26/11/2022 and 19/12/2022, aimed at the characterization of the atmospheric composition and at identifying pollutants transport over the Mediterranean, Red Sea and Arabian Sea. In this study, we present preliminary results from the remote sensing observations acquired during the cruise. The area of interest, surrounded by deserts and anthropogenic sources, has been recognized as a climate change hotspot due to extreme temperature increases and an important contribution to greenhouse gas emissions. Limited studies focus on the area because of limited and few observational data are available.

AREAD’s main objective was to contribute to the knowledge of trace gases and aerosol concentrations in the region and to complement with wintertime observations the AQABA campaign (24/06/2017-03/09/2017) performed in the same region during the summer season. The research vessel’s voyage included observations in the Suez Canal, one of the most heavily used navigational hubs in global trade routes. The on-board instrumentation included in-situ observations for trace gases (NO, NO2, O3, SO2, CO2, CH4) and aerosol optical, physical and chemical properties (PM1, PM10, particle sizes, aerosol spectral absorption and scattering). In addition, remote sensing of aerosol, clouds and boundary layer height (BL) was obtained with a VAISALA CL51 ceilometer and an automatic ship-photometer (CIMEL CE318T, modified for marine applications) included in AERONET.

The preliminary results suggest a change of regime between the Mediterranean and the Suez Canal. AOD levels remained below 0.1 for the first part of the cruise and increased to more than 0.2 after the entrance of the ship into the Suez Canal. Even though there was no significant variation in BL height which remained below 1km for most of the cruise, increased particle backscatter is observed within the BL and in elevated layers after the Suez Canal. Desert dust, trade ship emissions and pollution from Middle East fossil energy production plants could be some of the species contributing to the higher aerosol loading observed in the latter leg of the cruise.

 

Acknowledgment: The datasets presented in this research were acquired during the Atmospheric Research Expedition to Abu Dhabi (AREAD) on-board research vessel Jaywun, operated by the Environment Agency of Abu Dhabi (EAD), which is gratefully acknowledged. The ship-photometer is developed in the frame of AGORA-Lab joint laboratory (Laboratoire d’Optique Atmospherique from CNRS/University of Lille and CIMEL Electronique company).