The vertical aerosol type distribution above Israel – 2 years of lidar observations at the coastal city of Haifa

Abstract. For the first time, vertically resolved long-term lidar measurements of the aerosol distribution were taken in Haifa, Israel. The measurements were performed by a PollyXT multi-wavelength Raman and polarization lidar. The lidar was measuring continuously over a 2-year period from March 2017 to May 2019. The resulting data set is a series of manually evaluated lidar optical property profiles. To identify the aerosol types in the observed layers, a novel aerosol typing method developed at TROPOS is used. This method applies optimal estimation to a combination of the lidar-derived intensive aerosol properties to determine the statistically most-likely contribution per aerosol component in terms of relative volume. A case study that shows several elevated aerosol layers illustrates this method and shows e.g. that coarse dust particles are observed up to 5 km height over Israel. From the whole data set, the seasonal distribution of the observed aerosol components over Israel is derived. Throughout all seasons, and with the highest contributions in summer, autumn, and winter, coarse spherical particles like sea salt, due to the coastal site, but also hygroscopic grown continental aerosol that was transported over the Mediterranean Sea was observed. During spring, coarse non-spherical particles attributed to desert dust were the mostly observed particles. This is consistent with the distinct dust season in Spring in Israel. An automated time-height-resolved air mass source attribution method identifies the dust sources in the Saharan and the Arabian deserts. Fine mode spherical particles also contribute significantly to the observed aerosol mixture during the most seasons. These particles originate mainly from the industrial region at the bay of Haifa.