Weather and Sunlight

The Sun is the primary source of energy for the Earth system. Weather results from the interaction between incoming solar radiation, the atmosphere, the oceans, and the surface of the planet.

Rather than creating energy, weather redistributes and transforms it, influencing how much energy is available locally, when it arrives, and in which form.

Before reaching the ground, sunlight passes through the atmosphere, where it is partially absorbed, scattered, or reflected.

• Cloud cover affects the balance between direct and diffuse radiation.
• Aerosols and dust reduce overall irradiance.
• Humidity influences heat retention and infrared radiation.

Even under cloudy conditions, significant amounts of energy can still reach the surface, though in a more diffuse form.

Solar radiation is transformed into multiple forms of energy once it reaches the Earth. These transformations occur both naturally and through human technologies.

• Electrical energy: produced by photovoltaic cells.
• Thermal energy: captured by solar collectors or stored in materials.
• Chemical energy: generated by photosynthesis and emerging solar-fuel technologies.
• Mechanical energy: driven by temperature and pressure differences, producing wind.

Research projects explore how these pathways can be combined or optimised, for example by harvesting sunlight simultaneously for electricity and chemical production.

Several weather parameters directly influence how much usable energy is available:

• Irradiance: the primary driver of solar energy production.
• Temperature: affects efficiency of photovoltaic and thermal systems.
• Cloud cover: modulates variability and predictability.
• Wind: contributes to cooling and mechanical energy generation.
• Precipitation: influences surface conditions and long-term climate patterns.