Session
2022 session 6
Location
Space Dynamics Laboratory, Auditorium Rm C
Start Date
5-9-2022 10:50 AM
End Date
5-9-2022 11:00 AM
Description
The morphology and climatology of thermospheric neutral winds play an important role in ionospheric and thermospheric dynamics. Thermospheric neutral winds effect temporal and spatial variations of ionospheric plasma which plays an important role F-region dynamics. However, direct observations of thermospheric neutral winds are historically limited both temporally and spatially [1]. For example, interferometric methods for measuring thermospheric winds are restricted to nighttime observations and cloudless conditions and are limited to relatively few locations. Space-based observations made by cross-track measurements from accelerometers as well as onboard interferometers and spectrometers provide valuable information of thermospheric winds but coverage is inconsistent over a given location for all local times. Radio occultation (RO) measurements obtained from satellites profile the upper atmosphere and provide critical parameters associated with ionospheric dynamics, i.e. hmF2 and NmF2. These observations are abundant and embed information about the underlying thermosphere. Data assimilation is a technique that combines information from observations and a physical model. Observed data are assimilated into the model as a constraint for the physical equations that describe the dynamics of the system, which allows estimates of unobserved driving forces, e.g., the thermospheric neutral wind.
The Global Assimilation of Ionospheric Measurements Full Physics (GAIM-FP) model assimilates global maps of hmF2 and NmF2 from COSMIC radio occultation measurements to estimate magnetic meridional winds at low and mid-latitudes. The Thermospheric Wind Assimilation Model (TWAM) combines these magnetic meridional wind estimates with the equation of motion of neutral gas using a Kalman filter technique to provide climatology of the thermospheric wind components. Comparisons with the thermospheric wind estimates obtained from the update to TWAM were found to be with good agreement with the Horizontal Wind Model (HWM14) and ground- and space-based observations.
Ionosphere/Thermosphere Dynamics Obtained from COSMIC Satellite Observations
Space Dynamics Laboratory, Auditorium Rm C
The morphology and climatology of thermospheric neutral winds play an important role in ionospheric and thermospheric dynamics. Thermospheric neutral winds effect temporal and spatial variations of ionospheric plasma which plays an important role F-region dynamics. However, direct observations of thermospheric neutral winds are historically limited both temporally and spatially [1]. For example, interferometric methods for measuring thermospheric winds are restricted to nighttime observations and cloudless conditions and are limited to relatively few locations. Space-based observations made by cross-track measurements from accelerometers as well as onboard interferometers and spectrometers provide valuable information of thermospheric winds but coverage is inconsistent over a given location for all local times. Radio occultation (RO) measurements obtained from satellites profile the upper atmosphere and provide critical parameters associated with ionospheric dynamics, i.e. hmF2 and NmF2. These observations are abundant and embed information about the underlying thermosphere. Data assimilation is a technique that combines information from observations and a physical model. Observed data are assimilated into the model as a constraint for the physical equations that describe the dynamics of the system, which allows estimates of unobserved driving forces, e.g., the thermospheric neutral wind.
The Global Assimilation of Ionospheric Measurements Full Physics (GAIM-FP) model assimilates global maps of hmF2 and NmF2 from COSMIC radio occultation measurements to estimate magnetic meridional winds at low and mid-latitudes. The Thermospheric Wind Assimilation Model (TWAM) combines these magnetic meridional wind estimates with the equation of motion of neutral gas using a Kalman filter technique to provide climatology of the thermospheric wind components. Comparisons with the thermospheric wind estimates obtained from the update to TWAM were found to be with good agreement with the Horizontal Wind Model (HWM14) and ground- and space-based observations.