Sudden stratospheric warming effects on the mesospheric tides and 2-day wave dynamics at 7°S

Abstract

The dynamics of the equatorial mesosphere have been investigated during austral summers of 2004–2005, 2005–2006 and 2006–2007 from meteor radar measurements obtained at São João do Cariri, Brazil (7.4°S, 36.5°W), together with stratospheric northern hemisphere polar parameters. Some recent studies have demonstrated coupling between high latitude northern hemisphere major Sudden Stratospheric Warming (SSW) events and mesospheric–ionospheric disturbances, including the equatorial region. Here we have analyzed the tides, quasi-two-day planetary wave and local mean zonal wind variability in the equatorial upper Mesosphere and Lower Thermosphere (MLT) region during three austral summers and found that upper mesospheric dynamics at 7°S has been affected when a remarkable major SSW event took place in January 2006. The more intense tides and quasi-two-day wave amplitudes during the major SSW event are suggestive of an association between them and high planetary wave activity in the northern stratospheric winter.