| Autor: |
Присяжний, А. І., Підстригач, І. Я., Баран, О. А. |
| Zdroj: |
Journal of Physical Studies; 2024, Vol. 28 Issue 4, p1-9, 9p |
| Abstrakt: |
We propose three methods for calculating the areas of specific structures in the solar atmosphere, which are observed in images obtained within the visible spectral range. These methods allow us to calculate the area of each pixel within the selected region of the image by using correction factors, approximating with the area of two triangles, and through integration. Comparing these methods revealed their close correspondence for the most of the visible hemisphere of the Sun. The correction factors method is the simplest and quickest, so it is sufficient for all practical applications. The sunspot area was calculated based on a set of images from the Solar Dynamics Observatory (SDO) archive - flattened images of the Sun's white-light intensity pictured by HMI instrument. All calculations were performed both for the daily total area of the sunspots observed on the visible hemisphere of the Sun at a particular time and separately for their umbrae and penumbrae. The intensity thresholds for the umbra-penumbra and penumbra-photosphere transitions were determined relative to the average intensity of the quiet photosphere. We tracked the changes in sunspot area from 2012 to 2023, i, e, the period from the peak of solar activity cycle 24 to the approaching maximum of cycle 25, currently in progress. We compared our results with the data from the Solar Monitor project and found a strong correlation between these datasets (Pearson correlation coefficient is 0.91). We analyzed how the ratio of umbra area to the total sunspot area evolves across different phases of the solar cycle. We found that the average value of this parameter remains constant at 20% with no significant variations, except during the minimum phase. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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