Analysis of Tec Variation During June 21, 2020 Annular Solar Eclipse Over Addis Ababa and Djibouti
| dc.contributor.advisor | Elfagd, Yitagesu (PhD) | |
| dc.contributor.author | Sete, Shibre | |
| dc.date.accessioned | 2021-11-15T12:13:51Z | |
| dc.date.accessioned | 2023-11-09T11:26:43Z | |
| dc.date.available | 2021-11-15T12:13:51Z | |
| dc.date.available | 2023-11-09T11:26:43Z | |
| dc.date.issued | 2021-10-10 | |
| dc.description.abstract | On June 21, 2020, an annular solar eclipse happened. The annular eclipse's central path passed through parts of Central and Eastern Africa. A partial solar eclipse was visible across much of Africa and it traverses Ethiopia and Djibouti. During a solar eclipse the Moon blocks a portion of the solar radiation from reaching the Earth. Following the eclipse a decrease in the ionization is expected due to the obscuration of solar radiation, and thus a decrease in the amount of ionospheric total electron content (TEC). The e_ect of this partial solar eclipse on the ionospheric TEC was studied using two Global Positioning System (GPS) stations found in Addis Ababa and Djibouti. The objective of this thesis is to study the e_ect of the June 21, 2020 annular eclipse on the ionospheric TEC. Because eclipse geometry varies from eclipse to eclipse, it's not always clear whether a di_erence in ionospheric reaction is due to a change in eclipse time of occurrence, obscuration level, geometry, or background conditions such as: di_erent solar and geomagnetic activities, seasons, latitudes and longitudes. Therefore, individual eclipse studies are signi_cant. TEC data taken from the two GPS stations were used to examine the ionospheric behavior during the eclipse. The partial solar eclipse was observed to cause a signi_cant TEC depletion during the eclipse period at both stations. Which indicates that the amount of TEC in the ionosphere was a_ected by the decrease in solar radiation during the eclipse. The TEC measurements during the eclipse period were compared to two days before, two days after the eclipse period and three years of June 21 to make sure that the cause of the TEC depletion was not due to a daily variation in the ionosphere. A maximum TEC reduction of up to 35% were observed compared to the days after and before the eclipse. A time lag of 45 and 15 minutes were found between the maximum obscuration and a maximum TEC depletion over ADIS and DJIG, respectively. After the eclipse ended, the TEC began to return to normal levels and recovered fully after 1 hr over DJIG and 1 hr and 18 minutes over ADIS stations. The TEC reduction shows the partial solar eclipse a_ects the ionospheric TEC and since the ionosphere is mostly governed by the photoionization, the decrease in solar radiation causes the density of the ionosphere to decrease. The eclipse occurred during a period of low solar and magnetic activity. The reference days TEC data and the magnetic activity indicated the eclipse was the cause of the TEC depletion. Further research is needed to study the e_ect of the eclipse in the low latitude region as it can be a_ected by the equatorial ionization anomaly. | en_US |
| dc.identifier.uri | http://10.90.10.223:4000/handle/123456789/28666 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Solar Eclipse | en_US |
| dc.subject | Total Electron Content | en_US |
| dc.subject | Ionosphere | en_US |
| dc.subject | Equatorial Ionization Anomaly | en_US |
| dc.title | Analysis of Tec Variation During June 21, 2020 Annular Solar Eclipse Over Addis Ababa and Djibouti | en_US |
| dc.type | Thesis | en_US |