zonnevlekactiviteit
Zonnevlekactiviteit refers to the variation in the frequency and characteristics of sunspots observed on the solar photosphere. Sunspots are regions of intense magnetic field that appear darker than the surrounding photosphere because they are cooler. Their formation and evolution reflect the Sun’s magnetic dynamo processes, with the magnetic field reversing polarity approximately every 11 years. This period, called the solar cycle, is monitored through the international sunspot number, a long‑term index that counts both the number of individual spots and groups of spots.
During the ascending phase of a cycle the sunspot number rises, leading to increased solar magnetic activity,
Sunspot activity directly influences the Sun’s radiative output. The total solar irradiance (TSI) fluctuates by about
The study of zonnevlekactiviteit combines observations from ground‑based sunspot archives, spacecraft missions such as SOHO, SDO,