Air pollution severely impacts on climate; in particular, GHGs have a positive forcing on the Earth’s energy budget, which is enhanced by the direct radiative effect of black carbon particles. The rest aerosol species tend to counteract this tendency. The effect of the increase of atmospheric aerosol concentrations on the cloud properties is much more complex and highly uncertain. The atmospheric composition has been heavily perturbed by humans and considerable uncertainty also remains in our understanding of their impact on the carbon cycle. Oceans modulate the carbon cycle by contributing to the removal of atmospheric CO2 via physical, chemical, and biological processes. Atmospheric aerosol deposition on the oceans, however, can be an important source of nutrients for the marine environment, which modulates carbon uptake, and thus CO2 atmospheric concentrations.
In this frame, APCG operates in situ instrumentation supporting research on the gaseous and aerosol properties and effects on climatic parameters (e.g. radiation, temperature). In complement, we retrieve and utilize relevant experimental data from existing infrastructure, such as ACTRIS and PANACEA monitoring instrumentation located at remote locations. Our capacity in numerical modeling, includes earth system modeling (ESM) to investigate the potential ocean biogeochemistry perturbations due to changes in atmospheric deposition for the past and future atmosphere. Simulations of the physicochemical atmospheric interactions on the regional scale are systematically performed in order to identify the effects of atmospheric aerosols on radiation, cloud properties and atmospheric temperature.
Source: Myhre et al., 2013
Our activities include:
- Analyzing the physical and optical properties of aerosols to obtain information of the particle number size distribution and light absorption and scattering as well by means of well-established techniques. Understanding secondary atmospheric processes such as the new particle formation (NPF) is important for interpreting aerosol-cloud interactions, since the produced ultrafine particles (UFP; particles with diameter smaller than 100 nm) are important sources of cloud condensation nuclei (CCN). The assessment of the climatic impact of aerosols is supported by the determination of the near surface extensive and intensive properties (i.e., bsca, babs, SAE, AAE, SSA) through systematic in-situ measurements.
- Studying the direct radiative effects of atmospheric aerosols during intense air pollution episodes (e.g. RWB, wildfires, Saharan dust intrusions), as simulated by online-coupled atmospheric modeling.
- Deciphering the interactions between aerosols and clouds through studying the ability of aerosol particles to form cloud condensation nuclei (CCN) and subsequently cloud droplets based on their size and chemical composition, using state-of-the-art measurements and parameterizations. The ability of particles to act as CCN is also related to the indirect radiative effect via altering the number in clouds and thus their ability to scatter/ absorb the incoming solar radiation.
- Investigating the levels of greenhouse gases (GHGs) and their emission sources. By integrating such measurements, the gap for greenhouse observations in the Eastern Mediterranean is filled. The monitoring of CO, CO2, and CH4 provides significant information about the urban emissions and the global trends as well, contributing to the understanding of climate change.
- Developing an online atmospheric chemistry scheme of the main nutrients (i.e., nitrogen, phosphorus, and iron), taking into account dust minerals, bioaerosols and combustion aerosols.
- Studying the effect of state-of-the-art nutrient deposition fields on carbon-cycle via ocean bio-geochemistry calculations.