Measurements of Midlatitude Thermospheric Dynamics and Temperature

Computational Physics Inc, Springfield VA

Investigators

Abstract

This project will continue the measurements of winds and temperatures in the thermosphere (a region of atmosphere between about 80 km to 600 km above sea level) at Arecibo Observatory, Puerto Rico (started in 1980) and at Haystack Observatory, Massachusetts (started in 1989) using a highly sensitive instrument called Fabry-Perot interferometers (FPIs). The two observatories have two powerful radar systems called Incoherent Scatter Radars (ISRs) that can measure the ionized part of the atmosphere in the same region (also called ionosphere). Combination of such measurements are needed for realistic, physics-based modeling of the thermosphere-ionosphere system, and for effective forecasting of Space Weather. This FPIs used at Haystack Observatory and Arecibo Observatory are dual-beam imaging systems sampling the OI 6300Å (red) and 5577Å (green) airglow emissions with spectral resolutions that resolve the Doppler shift associated with the bulk flow of neutral species in the thermosphere. The data products include airglow brightness, temperature, line-of-sight wind velocity, meridional and zonal components of the wind velocity and velocity gradients at the nominal emission altitudes of 240 km and 97 km. 200-300 nights of data will be generated each year during this three-year project. This initiative maintains the FPIs, performs the observations, analyses the data, and posts the data in the public Madrigal data base each morning after data collection stops. New and archived data (since 1980 at Arecibo Observatory and 1989 at Haystack Observatory) will be used to achieve four scientific goals: 1) Test the validity of vertical winds measured with a monostatic FPI by performing a bistatic experiment to unambiguously isolate the vertical wind vector. 2) Gather hundreds of vertical wind measurements each month (past and future) and establish monthly velocity versus local time empirical models from polynomial fits to the data. 3) Investigate whether a long-term rotation of the average F-region wind vector detected in the years 1980-2010 continues from 2011-2023. If so, the long-term migration of the magnetic field orientation will be evaluated as a possible cause. 4) Evaluate a possible correlation between the Midnight Temperature Maximum and strong, upward vertical winds in the F-region thermosphere. A fifth project goal is an operational objective to establish real-time data product reporting for operational Space Weather forecasting. This research enhances infrastructures for research and education. The FPIs are available for community use at the facilities, and users can design and perform independent experiments. In addition, accurate and accessible (even in real-time) neutral wind measurements are an essential data element in responding to the challenge of Space Weather forecasting, which carries significant potential for broad societal benefit in the context of situational awareness for space-based navigation and communication assets. The instruments maintained by this project are also commonly used for projects in the vigorous Research Experience for Undergraduates programs at each facility. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.