Effects of January 2010 stratospheric sudden warming in the low-latitude ionosphere

The winter of 2009-2010 was marked by a significant stratospheric warming event peaking in the end of January 2010. Although this warming was not as strong as SSW events of 2008 and 2009, it presents a perfect opportunity to study the coupling between different atmospheric regions under less extreme circumstances. Peak stratospheric temperature at 90N and 10hPa level was reached on 22 January, and temperature remained above the long-term mean for over two-week period. Strong abatement in the zonal mean zonal wind at 60N was observed starting around January 10 and continuing well into March 2010, though wind changed the direction only for brief periods of time. The stratospheric circulation was determined mostly by a planetary wave 1, while the activity of planetary wave 2 remained close to the long-term mean level. We use GPS TEC and Jicamarca ISR data to study effects of this SSW event on low-latitude ionosphere. Our results indicate that disturbances in the upper atmosphere during the SSW event of 2010 are consistent with disturbances reported for other SSW cases. In particular, at 70W longitude tidal variation in TEC becomes prominent on January 25-26, 2010, after the peak in stratospheric temperature, and lasts for several days. The phase of this variation shifts to later local time, in agreement with other SSW events, but the amplitude is smaller, likely due to the weaker SSW event. We discuss different properties of the observed phenomena and demonstrate unique features of this time interval.