Item

Abstract

The depletion of plasma in the nighttime F region ionosphere is called the mid-latitude ionospheric trough (MIT). The objective of this study is to identify and describe the mid-latitude ionospheric trough by using new satellite data and expanding our understanding of the MIT phenomenon. To evaluate the MIT, we used electron density in-situ data derived from GRACE satellite K-Band Ranging system (KBR) measurements. The trough was examined using data collected between 2002 and 2015, including high and low solar activity periods. We analyze the characteristics of the mid-latitude ionospheric trough (MIT) in both the Northern and Southern Hemispheres. The MIT is characterized by its trough’s minimum position, width, depth, and probability. We investigated how MIT parameters were affected by the magnetic local time, geographic distribution, seasons, and solar and geomagnetic activity conditions, including solar wind plasma speed, interplanetary magnetic field components, and high-resolution geomagnetic indices SYM-H and Hp30. In this study, we demonstrate the elliptical distribution of the mean location of the trough minimum over three seasons for the Northern and Southern hemispheres and the MIT parameter dependency on high-resolution geomagnetic indices. Our findings confirm and extend earlier research on MIT. The obtained dependencies related to MIT climatology and occurrence probability can be used to validate existing MIT models and create new MIT models since it has not yet been represented in commonly used 3D electron density models, such as IRI, NeQuick, NEDM2020, etc. The integration of an MIT model may improve the performance of the 3D electron density models.