CEDAR: Optical Measurements of Daytime Thermospheric Dynamics and Nighttime Mesospheric and Thermospheric Dynamics at the Magnetic Equator

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The investigators will operate a Second-generation Optimized Fabry-Perot Doppler Imager (SOFDI) at the Huancayo Geophysical Observatory in Peru to measure mesospheric and thermospheric winds. The main objective is to determine the way in which zonal wind direction is linked to the occurrence of equatorial spread-F and scintillations at the magnetic equator. A problem in understanding the complex electrodynamics of the equatorial region has been to explain the day-to-day variability of the effects of the disturbed ionosphere, represented by the phenomena of bubbles, scintillations, bottomside spread F, and equatorial spread F. While other factors play a role in these phenomena, the change in the semi-diurnal thermospheric tidal activity that modulates the speed of the zonal wind across the evening twilight terminator may be a key factor. Such variations of the zonal wind speed may affect the timing for the development of the F-region dynamo and modify the likelihood of the development of plasma instabilities. The SOFDI instrument is designed for both nighttime and dayglow measurements of airglow intensities and atmospheric winds and temperatures at remote locations. The observations will be made in coordination with an all-sky imager and the Jicamarca incoherent scatter radar. The investigators will also investigate the possible effects of atmospheric gravity waves on irregularity growth. Irregularities in the equatorial ionosphere produce scintillations that affect the operation of navigation and communications systems. This study will help develop models that can forecast the occurrence of scintillations to protect these systems from deleterious space weather effects.