Modelo empírico das componentes dos ventos neutros termosféricos no setor americano baseado em dados do satélite UARS-WINDII para períodos geomagneticamente calmos

Abstract

Thermospheric Neutral Winds (TNW) play a crucial role in the dynamics of the ionosphere by acting directly on the plasma drift. The TNW are the main maintenance mechanism of the nocturnal ionosphere. In addition, the TNW influence the behavior of Appleton Anomaly. The componentes of the TNW are usually measured by equipments such as Fabry-Pérot interferometer (FPI), Incoherent Scatter Radar (ISR), and science payloads onboard in rockets. However, these measurements are localized and offer low spatial coverage. With the advance of satellite observations, it was possible to obtain better spatial and temporal data coverage of the TNW’s components. On the other hand, TNW models have become an important tool for understanding the behavior of the dynamics of the neutral and ionized atmosphere above the mesopause. However, some models disagree about the behavior of the TNW at the altitudes of the thermosphere, especially in the South American Sector, mostly due to the lack of in situ measures for calibration. This work presents the TNW model “Empirical Averaged Thermospheric Wind Model (EArTh Wind)” that is based on a statistical study of the records obtained by the UARS satellite, using the onboard Wind Imaging Interferometer (WINDII) equipment from 1992 to 1997. The EArTh Wind represents the longitudinal average of TNW at the altitude of 250 km, within ±50o of geographic latitude for solar and geomagnetic conditions of Φ10,7m = 87,83 SFU and kpm = 2- (1,58), respectively. The EArTh Wind describe the seasonal (day of the year) and local time variability of these mean TNW evaluated by Fourier series. The behavior of the simulations obtained by the EArTh Wind show a good agreement with the climatology of the TNW components observed by the UARS satellite at different periods of the year. The statistical parameters used to evaluate the EArTh Wind presented good agreement whith the dataset for both TNW’s components, especially during the equinoxes. Particullary, a better agreement between the dataset and the zonal component was observed for all periods of the year. The statistical tests indicated that the latitudinal model EArTh Wind resembles the 2014 version of the Horizontal Wind Model, (HWM14), especially for the meridional component. In the localized comparison between the EArTh Wind FPI data from in Arecibo (18.35o N and 66.75o W), the meridional component showed good agreement, also comfirmed by the comparative statistical parameters obtained.