Long-term Variations in the Intensity of Plages and Networks as Observed in Kodaikanal Ca-K Digitized Data
| Autor: | Jagdev Singh, Somasundaram Kameshwaran Rathina, Ravindra Belur, Muthu Priyal |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Physics
Plage Sunspot 010504 meteorology & atmospheric sciences FOS: Physical sciences Astronomy and Astrophysics Atmospheric sciences 01 natural sciences Intensity (physics) Solar cycle Solar cycle 19 Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Observatory Temporal resolution 0103 physical sciences 010303 astronomy & astrophysics Chromosphere Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences |
| Popis: | In our previous article (Priyal et al. in Solar Phys. 289, 127, 2014) we have discussed the details of observations and methodology adopted to analyze the Ca-K spectroheliograms obtained at the Kodaikanal Observatory (KO) to study the variation of Ca-K plage areas, enhanced network (EN), and active network (AN) for Solar Cycles, namely 19, 20, and 21. Now, we have derived the areas of chromospheric features using KO Ca-K spectroheliograms to study the long-term variations of Solar Cycles 14 to 21. The comparison of the derived plage areas from the data obtained at the KO observatory for the period 1906-1985 with that of MWO, NSO for the period 1965-2002, earlier measurements made by Tlatov, Pevtsov, and Singh (Solar Phys. 255, 239, 2009) for KO data, and the SIDC sunspot numbers shows a good correlation. The uniformity of the data obtained with the same instrument remaining with the same specifications provided a unique opportunity to study long-term intensity variations in plages and network regions. Therefore, we have investigated the variation of the intensity contrast of these features with time at a temporal resolution of six months assuming that the quiet-background chromosphere remains unchanged during the period 1906-2005 and found that the average intensity of the AN, representing the changes in small-scale activity over solar surface, varies with solar cycle being less during the minimum phase. In addition, the average intensity of plages and EN varies with a very long period having a maximum value during Solar Cycle 19, which was the strongest solar cycle of twentieth century. 21 pages, 11 Figures |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|