Research
The term middle atmosphere refers to the region of Earth’s atmosphere between the tropopause (∼10-18 km) and turbopause (∼100-110 km). Before the satellite era, the middle atmosphere was a difficult region to study because it was out of reach of most observing techniques. Satellites with modern instruments and measurement techniques have revealed a highly intertwined and intricate world—the middle atmosphere is sensitive to variations in input from above and below, both natural and anthropogenic, and it in turn affects the atmosphere above and below.
The figure below illustrates some of the phenomena most relevant to the research we conduct. Energetic particles from the Sun stream into the atmosphere in the polar regions and light up the aurorae. Thin ice clouds called polar mesospheric clouds form near the cold summer mesopause and shimmer against the fading twilight. The polar vortex dances with the anti-cyclones around the winter pole, growing larger with increasing altitude, sometimes disappearing in a matter of days in a dramatic sudden stratospheric warming. In the last decade sudden stratospheric warming events have been the strongest ever observed, and in the aftermath the stratopause reforms at an altitude characteristic of the mesopause. All of these seemingly unrelated phenomena are in fact coupled through various processes in the middle atmosphere. For example, air that has enhanced nitric oxide from energetic particle precipitation can be transported from the mesosphere and lower thermosphere down through the polar vortex to the stratosphere, where it can interfere with ozone catalytic cycles. The changes in ozone have the potential to impact the circulation in ways that could even be felt in the opposite hemisphere, which has implications for polar mesospheric clouds. These connections and teleconnections form an integral part of our research. For a more in depth discussion, explore the individual topics through the links on the left. Thank you for your interest in our research—we hope you enjoy learning something new and fascinating about the world around you!
Acknowledgments
Funding for this research has been provided by NSF and NASA. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the funding agencies.
Specific grants include:
JPL1350080, NNG04GF39G
