Atmospheric aerosol is a complex and dynamic mixture of solid and liquid particle from natural and anthropogenic sources. Aerosols today play crucial role in global climate effects and according  to IPCC report the understanding of their role in these processes of climate change are still very low. From the hygroscopic point of view we can define two principal types of aerosols: 

Hydrophylic aerosols - Can adsorb water vapor from surroundings and ultimately dissolve. The examples of this aerosol type are sulfate and sea-salt aerosols. These aerosols are the most important for my study because they become larger and more scattered with increasing relative humidity of air. 

Hydrophobic aerosols - Do not adsorb water vapor from surroundings. The example of this type is mineral dust aerosol. The most mineral dust particles are hydrophobic at the time of entrainment. Hydrophobic aerosols do not nucleate droplets in clouds.

Those aerosols that are hygroscopic particles can absorb water from the environment, after this their optical properties change. Also aerosols can be activated as cloud condensation nuclei becoming cloud particles. So as we can see from that classification, humidity is a very important factor of aerosol behavior and growth in the atmosphere, and the reason why we should devote more time to this type of research is low level of understanding how aerosols really affect our climate system indirectly.

The main aim of my work is to asses the correlation between aerosol optical parameters and relative humidity for various types of local and long-range transported aerosols. Also there is a task to set up statistically significant database of aerosol optical properties and database of water vapor mixing ratio and also vertical profiles of relative humidity.

Main data of the work will be derived from Multiwavelength Lidar RALI and HATPRO Microwave Radiometer. Apart of this to simulate aerosol optical properties OPAC direct simulations will be used and to asses the aerosol types and investigate the range variations of their optical properties Backtrajectory HYSPLIT model will be included in work.