Evidence of Tropospheric 90 Day Oscillations in the Thermosphere.

Autor: Gasperini, F., Hagan, M. E., Zhao, Y.
Zdroj: Geophysical Research Letters; 10/28/2017, Vol. 44 Issue 20, p10,125-10,133, 9p
Abstrakt: In the last decade evidence demonstrated that terrestrial weather greatly impacts the dynamics and mean state of the thermosphere via small-scale gravity waves and global-scale solar tidal propagation and dissipation effects. While observations have shown significant intraseasonal variability in the upper mesospheric mean winds, relatively little is known about this variability at satellite altitudes (∼250-400 km). Using cross-track wind measurements from the Challenging Minisatellite Payload and Gravity field and steady-state Ocean Circulation Explorer satellites, winds from a Modern-Era Retrospective Analysis for Research and Applications/Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model simulation, and outgoing longwave radiation data, we demonstrate the existence of a prominent and global-scale 90 day oscillation in the thermospheric zonal mean winds and in the diurnal eastward propagating tide with zonal wave number 3 (DE3) during 2009-2010 and present evidence of its connection to variability in tropospheric convective activity. This study suggests that strong coupling between the troposphere and the thermosphere occurs on intraseasonal timescales. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index