PALMER STATION FPI
The upper atmosphere and ionosphere over the Antarctica Peninsula have many unique characteristics related to the mesospheric and thermospheric winds due to its unusual geographic and geomagnetic locations. Because of lack of observations, the upper atmosphere in this region is not well understood.
The Antarctica Peninsula is the only part of Antarctica continent that extends into the zone of strong westerly surface wind. The Peninsula blocks the wind. Consequently, the air carried by the wind has to rise up over the land. This interaction between the land and the strong wind generates what are called mountain waves. These mountain waves can propagate upward into the stratosphere and mesosphere. As the waves travel to higher altitudes, they carry with them momentum and energy into the stratosphere and mesosphere changing the dynamics of the upper atmosphere and creating unique regional characteristics. Only in recent years, the effect of these waves are observed and studied extensively. However, there are still many unknowns.
The ionosphere near the Antarctica Peninsula is unusual in the austral summer. Its density is higher at the mid-night than that at the noon; that is opposite to the ionosphere behavior anywhere else around the world. This phenomenon is called the Weddell Sea Anomaly. Past studies have shown that the thermospheric winds may be responsible for this. However, because there have never been any successful thermospheric wind observations in this region, such hypothesis cannot be truly substantiated.
The Antarctica Peninsula region has relatively high geographic latitudes (~64S) compared to its geomagnetic latitude, which is only about ~54 deg. Ionosphere is strongly affected by the geomagnetic latitude; on the other hand, the thermospheric winds depend on the geographic location. The ionosphere is also influenced by the thermospheric winds. Hence, the ionosphere over the Antarctica Peninsula has mid-latitude characteristics because of its geomagnetic location and high latitude qualities due to its high geographic latitude. This unusual combination is the most likely reason the ionosphere behaves differently. The only way to have a better understanding of the ionosphere in this region is have more thermosphere observations.
To further explore the upper atmosphere and ionosphere over the Antarctica Peninsular region, a Fabry-Perot interferometer (FPI) for Doppler remote sensing of the mesosphere and thermosphere was deployed at Palmer station (64S, 64W) in 2010. It is the first successful FPI instrument in the region. Observations from Palmer and other Antarctica locations will provide the necessary data to help unlock many mysteries about the upper atmosphere and ionosphere in this region.
In addition to observations, modeling effort will also be part of the investigation. Both the empirical and first principle models will be used to simulate the upper atmosphere conditions over the Antarctica Peninsular region. Comparison between observations with models can help understand the underlying principle driving the mesosphere and thermosphere dynamics. Conversely, such comparisons can also verify model results and further improve the models.
RESOLUTE BAY FPI
The FPI at Resolute, Canada has the following scientific objectives:
- Establish an observational program to complement the NCAR upper atmosphere modeling program
- Continue Fabry Perot Interferometer observations at Resolute, Canada to support future AMISR project
- Provide mesosphere and thermosphere wind and temperature data
- Support collaborative studies of atmospheric tides and planetary waves
- Support space-based observations (TIDI)