On new two-dimensional UHF radar observations of equatorial spread F at the Jicamarca Radio Observatory

We describe a mode for two-dimensional UHF (445 MHz) radar observations of F -region irregularities using the 14-panel version of the advanced modular incoherent scatter radar (AMISR-14). We also present and discuss examples of observations made by this mode. AMISR-14 is installed at the Jicamarca Radio Observatory (JRO, 11.95°S, 76.87°W, ~ 0.5° dip latitude) in Peru and, therefore, allows studies of ionospheric irregularities at the magnetic equator. The new mode takes advantage of the electronic beam-steering capability of the system to scan the equatorial F -region in the east–west direction. Therefore, it produces two-dimensional views of the spatial distribution of sub-meter field-aligned density irregularities in the magnetic equatorial plane. The scans have a temporal resolution of 20 s and allow observations over a zonal distance of approximately 400 km at main F -region heights. While the system has a lower angular and range resolution than interferometric in-beam VHF radar imaging observations available at Jicamarca, it allows a wider field-of-view than that allowed with the VHF system. Here, we describe the mode, and present and discuss examples of observations made with the system. We also discuss implications of these observations for studies of ESF at the JRO. Graphical abstract Keypoints A new mode for two dimensional observations of F-region irregularities in the magnetic equatorial plane using AMISR-14 is described. Examples of observations are presented and illustrate the ability of the system to capture the genesis, evolution, and decay of sub-meter ESF irregularities. The benefits of the new mode are highlighted and implications of the new observations for studies and better understanding of ESF are discussed.