CLAVEL: CLimate-relevant clouds and aerosols: A holistic Vertically-rEsoLved anaLysis of cirrus clouds and particles in dusty and marine environments concerning their radiative impact on Climate Change

CLAVEL is a Project funded by the Agencia Estatal de Investigación (AEI), Ministerio de Ciencia, Innovación y Universidades (PID2023-151666NB-I00). Period: 01/09/2024 – 31/08/2027. PI: Carmen Córdoba Jabonero (cordobajc@inta.es), Atmospheric Research and Instrumentation Branch/Área de Investigación e Instrumentación Atmosférica (AIIA).

Description

The impact of aerosol particles and clouds, and their interactions, on climate is one of the most challenging fields of study in atmospheric research, mainly due to its implications on the radiative balance of the Earth-atmosphere system. The 2021 Intergovernmental Panel on Climate Change (IPCC) highlighted that cloud representation and aerosol-cloud interactions (ACI) present significant uncertainties when refining the prediction of future climate scenarios. Indeed, ACIs represent one of the main nucleation mechanisms involved in cloud formation. Thus, aerosols can act as cloud condensation nuclei (CCN), promoting the formation of cloud droplets, and as ice-nucleating particles (INP), giving rise to ice clouds. Among those, dust, widely studied in relation to ACI, but less so regarding its role in extreme cases (e.g. heatwaves-HW), and marine aerosols, which are much less investigated, even though they also serve as a good reservoir of particles for CCN/INP. Furthermore, in contrast to heterogeneous nucleation, the degree of understanding of the climatological implications of pure ice clouds (e.g. cirrus; homogeneous nucleation) is rather low. The starting hypothesis is based on the need to improve our knowledge of their properties and impact on climate, either separately or combined in terms of ACI. Therefore, the overall objective is to carry out a comprehensive study, with vertical resolution, of those aerosols (e.g. dust and marine particles) and ice clouds (cirrus) relevant to climate, as well as their ACI potential. For this purpose, an advanced methodology based on the synergistic combination of the use of active (lidar) and passive (solar/lunar photometry) remote sensing from ground and satellite together with validated CCN/INP parameterizations, plus meteorological data, will be implemented to perform: (1) advanced study of aerosol particles in representative environments (dust, marine) by retrieving their properties under different atmospheric conditions, including extreme events (intense dust intrusions and associated HW); (2) statistical analysis of ice cloud properties under homogeneous nucleation conditions (e.g. cirrus clouds), including estimation of the most relevant parameters for clouds associated with their radiative effect (ice content and effective radius); (3) in relation to (2), estimation of the radiative effect of cirrus clouds by adapting radiative transfer models; and (4) determination of the predicted concentration of aerosol-induced CCN and INP, with relevance in meteorological and climate models.

This proposal represents a collaborative project between INTA, which leads it from its station in El Arenosillo/Huelva (frequently exposed to the arrival of Saharan dust intrusions), and researchers from two international institutions, the University of Évora-Institute of Earth Sciences (UE-ICT, Portugal) and the University of La Réunion (UR, France), that have, in addition to stations frequently affected by Saharan dust intrusions (Évora) and Sahel biomass burning (La Réunion Island), marine remote sensing facilities, respectively, in the Azores Islands (Atlantic Ocean) and La Réunion Island (Indian Ocean). These stations are within the framework of ACTRIS/EARLINET and NASA MPLNET and AERONET. In addition, this project is important for the recent ESA/JAXA EarthCARE mission (May 2024), whose main objective is focused on aerosol-cloud-radiation interactions. In fact, INTA together with UE-ICT and UR is already participating in its calibration/validation activities. Additionally, results expected in this project are directly related to other INTA projects involved in planetary missions, such as the development of a miniaturized lidar system (MiLi) for application to the study of dust particles and ice clouds on Mars.

CLAVEL project is within the framework of the AIIA research line: Vertical impact of aerosol particles and clouds on the atmosphere and climate by using active (lidar) and passive (photometry) remote sensing techniques from space and ground-based platforms. Extrapolation to planetary missions.