Stratospheric Effects on the Lower Thermospheric Semidiurnal Tides (Invited)
Abstract
Vertical coupling is a key factor influencing the lower thermospheric semidiurnal tide, which is a prominent dynamic feature in the region. The stratospheric effect on the semidiurnal tide is complex and also latitude dependent. Therefore, a long term global observation is needed to provide a comprehensive view. The TIMED TIDI lower thermospheric neutral wind observations during the past eight years can provide such a global coverage. Additional ground based optical measurements can cover short term small scale changes. Based on the TIDI and ground based observations, we examine the stratospheric effect on the lower thermospheric semidiurnal tides. We will focus on the QBO and sudden stratospheric warming events (SSW) related changes. TIDI data set is long enough to examine possible QBO related variations and covers several SSW events. During some of the SSW events, we observed an enhancement in the westward zonal wavenumber 2 semidiurnal tide (SW2). That is different from some simulation results, which show an increase in the westward zonal wavenumber 1 semidiurnal tide (SW1). The increase in the SW2 could be due to an increase in the polar stratospheric ozone during SSW. Further study and model simulation are needed to verify this hypothesis.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMSA21B..01W
- Keywords:
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- 3332 ATMOSPHERIC PROCESSES / Mesospheric dynamics;
- 3334 ATMOSPHERIC PROCESSES / Middle atmosphere dynamics;
- 3369 ATMOSPHERIC PROCESSES / Thermospheric dynamics;
- 3389 ATMOSPHERIC PROCESSES / Tides and planetary waves