Case study on complex sporadic E layers observed by GPS radio occultations

Abstract. The occurrence of sporadic E (E_s) layers has been a hot scientific topic for a long time. The GNSS (global navigation satellite system)-based radio occultation (RO) has proven to be a powerful technique for detecting the global Es layers. In this paper, we focus on some cases of complex E_s layers based on the RO data from multiple missions processed in UCAR/CDAAC (University Corporation for Atmospheric Research (UCAR) the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Data Analysis and Archive Center (CDAAC)). We first show some examples of multiple E_s layers occurred in one RO event. Based on the evaluations between colocated simultaneous RO events and between RO and lidar observations, it could be concluded that some of these do manifest the multiple E_s layer structures. We then show a case of the occurrence of E_s in a broad region during a certain time interval. The result is then validated by independent ionosondes observations. It is possible to explain these complex E_s structures using the popular wind shear theory. We could map the global E_s occurrence routinely in the near future, given that more RO data will be available. Further statistical studies will enhance our understanding of the E_s mechanism. The understanding of E_s should benefit both E_s-based long-distance communication and accurate neutral RO retrievals.