Analyzing the cloud-induced aerosol modifications by combination of remote sensing techniques (ACI-AMORES)

Abstract

Climate change is one of the most significant challenges that humankind currently faces. Observations show a warming of the planet since preindustrial times that has amplified and accelerated since the 1950s. Greenhouse gases are indeed not the only anthropogenic driver of climate change. It is now widely understood that anthropogenic aerosols have masked a fraction of the warming effect expected from the increase in greenhouse gases, since the beginning of preindustrial times. The possible interaction and modification of cloud properties due to aerosols is one of the most poorly understood mechanisms within climate studies, resulting in the most significant uncertainty as regards radiation budgeting. Hence more research is necessary to better understand how aerosols affect climate change and how climate change affects the distribution of aerosols in our planet's atmosphere. At present, outstanding questions are: To what extent are various measures of aerosol-cloud interaction (ACI) robust and consistent? What are the factors affecting the magnitude of ACI (e.g., cloud type, water phase, dynamics, aerosol composition and size)? Is the variability in metrics of ACI found in the literature due to physical processes, measurement uncertainties, observational approaches, or a combination of all of these? The general objective of this exploratory project is contributing to increasing the knowledge of the role of the atmospheric aerosol in the Earth's climate, thus reducing the uncertainties associated to cloud, aerosol, radiation interaction by three specific objectives: (i) to be familiar with different databases for the study of clouds and atmospheric aerosol particles acquired in the Amazon forest (Manaus, Brazil) and Granada (Spain), as representative of pristine and urban atmospheric conditions, respectively; (ii) to explore different alternatives for the study of the modification of aerosol properties induced by clouds, using different ground based remote sensing techniques, both passive and active; and (iii) to use the combination of different remote sensing techniques to study changes in the optical properties of aerosols in the so-called twilight zone for the areas of Amazon forest (Manaus, Brazil) and Granada (Spain). (AU)