Enhanced synergetic retrieval of Aerosols, Clouds and Water Vapor properties in Arctic and Antarctic Regions (ePOLAAR)

The determination of aerosol, water vapor and cloud properties in Polar Regions is a key task to increase our knowledge about climate change and its impact in these areas. In the previous POLARMOON project, special emphasis was made on the new generation of photometers, able to provide time series of aerosol and water vapor data that are not interrupted during the polar night, establishing these measurements at the stations of ALOMAR-Andenes (Norway), Ny-Ålesund (Svalbard) and Marambio (Antarctica). The installation of sky cameras with new features allows, together with complementary instrumentation existing in those stations, the study of clouds. Long time series are the only way we have to provide data from which trends and climatologies can be extracted, a necessary step for the understanding of certain phenomena. In the Arctic, studies on aerosols reveal their strong seasonality, as well as the fact that high turbidity events are due to long-range transported air masses. In
Antarctica, the low aerosol concentration and the environmental conditions in the polar night constitute a huge challenge at the experimental level. Within this framework, we consider for this proposal:

• To continue with the measurements and generation of data on the properties of atmospheric aerosols, clouds and water vapor for the construction of long data sets, polar night included, at the stations of ALOMAR-Andenes, Ny-Ålesund and Marambio, as well as expand them to the Spanish base Juan Carlos I.
• The determination and characterization of a wide number of physicochemical and radiative properties of these three atmospheric components, through the application and optimization of new algorithms that suppose a methodological innovation. An example is the inversion algorithm for aerosol studies GRASP (Generalized Retrieval of Aerosol and Surface Properties), which allows combining and enhancing the synergy between data obtained by different instruments (photometer, all-sky camera, ceilometer, lidar, radiometer, satellite sensors).
• The evaluation of the radiative balance at ground level and the radiative forcing of these three components, which require experimental measurements and three-dimensional radiative transfer models, in order to better model the cloud field and to account for the earth-ocean interaction in the surface albedo.

In short, thanks to the installation of new radiometric instrumentation of the POLARMOON project in polar areas and the data generated, this new proposal intends to continue expanding these databases and apply new methodologies to advance the joint characterization of a large number of aerosols, clouds and water vapor properties, all of which are necessary for the study of climate change. This constitutes an innovative and ambitious proposal, which contributes to fulfilling the obligation to create high level science in the polar areas, based on multidisciplinarity and collaboration with other research groups. All this represents a challenge in which Spain is committed, both for its membership in the Antarctic Treaty and for its status as Observer Member of the Arctic Council, with presence in different Working Groups of the International Arctic Science Committee.