A Statistical Analysis of Global Ionospheric E‐Layer Scintillation During 2007–2014

Abstract

AbstractThis paper presents the global three‐dimensional morphology and seasonal variation of the scintillation index at E‐layer altitudes varying from 70 to 140 km. An attempt is conducted to analyze the scintillation distribution in different latitude bins and to explore solar and geomagnetic activity‐dependent characteristic of E‐layer scintillations. The scintillation index is derived from the signal‐to‐noise ratio intensity fluctuations of L1 channels in GPS radio occultation (RO) using the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) during 2007–2014. The results show that the summer scintillation index has the greatest values, followed by the winter, autumn, and spring months. The summer scintillation is in close connection with the solar radiation intensity and sunshine duration, but it exhibits seasonal asymmetry whereby the summer scintillation in the northern hemisphere is more intense than in the southern hemisphere. Meanwhile, the scintillation in the autumn hemisphere is slightly more intense than in the spring hemisphere in approximately midlatitude regions during most daytimes. The conspicuous scintillation activity in the middle and low latitudes starts post‐sunrise and often persists until post‐midnight. Some observed results show that the greatest scintillation occurrence rate of the latitude profile occurs at approximately sunset and at an altitude range of 100–120 km in the middle‐low latitudes. Additionally, the enhanced solar activity possibly can result in the slight decrease of scintillation occurrence, and geomagnetic activity has slight effect on E‐layer scintillation in most cases.