NSF Award
2411430
The stratospheric polar vortex is a belt of westerly winds in the midlatitudes that occurs during the winter months. The Arctic polar vortex is highly variable; sometimes it is weak and distorted while other times it is strong. Vortex strength is known to impact weather in the troposphere and variability in the mesosphere, thermosphere, and ionosphere. The state of the polar vortex is predictable up to two weeks in advance, so knowledge of the vortex state may increase predictability in other regions of the atmosphere, including the ionosphere. The ionosphere is critical for both communication and navigational signals; when the ionosphere is disturbed these signals are disrupted. In this work, the investigators will use the state of the polar vortex to explain thermospheric neutral winds, composition, and the state of the ionosphere at northern midlatitudes. The proposal work will support two early career scientists and three female scientists. Training of a high-school student at University of Colorado, Boulder and several undergraduates through Research Experience for Undergraduate (REU) program at MIT, Haystack Observatory is envisioned.<br/><br/>It is known that polar vortex impacts on the thermosphere and ionosphere are modulated by vortex strength. At one extreme, the polar vortex is weak and is associated with Sudden Stratospheric Warmings (SSWs). Extensive observational and modeling studies of weak vortex states have elucidated the changes in thermospheric temperature, wind, wave amplitudes, composition, and ionospheric Total Electron Content (TEC), along with the mechanisms driving these changes. In contrast, relatively little is known about thermospheric and ionospheric impacts during strong polar vortices. The work seeks to address the impacts of strong polar vortex on ionospheric electron densities, thermospheric composition, and winds. The team will also explore if ionospheric electron density changes are driven primarily by composition, neutral winds, or electric fields during such events. This study will use superposed epoch analysis, empirical models, and case studies of moderate and strong vortex states, leveraging observations of winds from Fabry Perot interferometers, ionospheric parameters from GNSS TEC, incoherent scatter radars, and ionosondes, and satellite observations of thermospheric composition. Whole atmosphere modeling results will be compared to the observations.<br/><br/>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.
