Heliophysics spans a wide range of disciplines covering the study of the Sun and the different Solar System bodies, such as Earth and other planets, moons, comets, and asteroids, and their interactions with the Sun, focusing on plasma and atmospheric processes. A grass-roots effort has been recently started toward establishing a European Heliophysics Community (https://www.heliophysics.eu/). This white paper outlines the motivation, priorities, and a future vision of Heliophysics in Europe.

This paper describes new humidity measurements performed with the humidity instruments of the MSL, Mars 2020 and ExoMars missions. Special facilities are needed to create Martian conditions, and a measurement campaign was performed at the German Aerospace Center (DLR) to obtain datasets for REMS-H, MEDA HS and METEO-H instruments. The results from the campaign improved the humidity data we receive from MEDA HS/Perseverance and can further improve the existing Martian relative humidity data.

The 1-D column model has been used extensively in studying the Martian atmosphere. In this study, we investigated the sensitivity of the column model to its initialization. The results of the model were compared with Curiosity rover measurements. The initial value of airborne dust and surface temperature had the greatest influence on the temperature prediction, while the initial atmospheric moisture content and the shape of the initial moisture profile modified the humidity prediction the most.

Combining short-time forecast models, standardized interfaces to a wide range of environment detectors and a flexible user access interface, CITYZER provides decision-making authorities and private citizens with reliable information about the near-future development of critical environmental parameters like air quality and rain. The system can be easily adapted to different areas or different parameters. Alarms for critical situations can be set and used to support authority decisions.

We analysed data from radiation monitors aboard different spacecraft such as Rosetta and Integral. From the data, we extracted the evolution of galactic cosmic rays as a function of time (over a full solar cycle) and position (from 1 to 4.5 AU). In the main results, we confirm the overall evolution (anti-correlation) of the fluxes with respect to the solar activity. We found a surprising result, which is a decrease in the flux of galactic cosmic rays around comet 67P.