Effect of Stratospheric Winds on GPS-TEC Over Turkey

Abstract

The lower ionosphere (50-100 km) is still much less known than the upper ionosphere due to the inability to measure in situ, the predominance of highly complex chemical processes, and the dominance of solar and geomagnetic processes meteorological processes from the lower atmosphere. This study investigates the relationship between total electron content (TEC) and the lower atmosphere (wind speed in the stratosphere). The results were compared by effects of the geomagnetic field and solar parameters on ionospheric TEC over Turkey. Depending on the latitude and longitude, the investigations were made for GPS stations located at Ankara, Pozant & imath;, Samsun, Istanbul and Erzurum in Turkey. The relationship between TEC and wind speed was statistically analyzed for 2015 year using regression analysis. Regression analysis was performed separately for the solar (IMF_Bz and F10.7) and the geomagnetic field (Kp and Dst) conditions. In the regression models established for the geomagnetic situation, it was observed that the explainability rate for the geomagnetic condition was higher than the explainability rate of the models established for the solar condition at all stations except station Erzurum. It was determined that the effect of wind speed on TEC in stations Pozant & imath; and & Idot;stanbul was smaller in geomagnetic conditions than in solar conditions, while it was greater in stations Ankara, Samsun and Erzurum. While the effect of wind speed on the TEC is greater than the effect of the geomagnetic Dst index, it is smaller than the Kp index at all stations except station & Idot;stanbul. It was observed that the effect of IMF_Bz index on TEC was greater than the effect of wind speed at all stations. It is known that the ionosphere is predominantly affected by the lower atmosphere and meteorological processes, especially up to the mesosphere heights. With this study, it has been seen that this effect also exists in the atmosphere of Turkey. For this reason, taking into account the stratospheric winds in the studies to be carried out on TEC will provide clearer results.