Ashique Vellalasserey (IAP) Long-term trends and solar cycle response of Noctilucent Clouds

Ashique Vellalasserey (IAP) wird auf unserem IAP-Kolloquium einen Vortrag zum Thema "Long-term trends and solar cycle response of Noctilucent Clouds" halten.

Zusammenfassung:

Noctilucent clouds (NLCs) consist of ice particles and are the highest clouds in the Earth's atmosphere, occurring 80-85 km above the Earth's surface in the extremely cold (~130K) summer mesopause region at mid and high latitudes. The formation of NLCs requires extremely cold background temperatures and the presence of water vapor (H2O). Due to their high sensitivity to temperature and water vapour concentration, NLCs have been proposed as important tracers for background atmospheric conditions in the summer mesopause region. In this research, the influence and effects of the 11-year solar cycle on NLCs, background water vapor, and temperatures are investigated using model simulations. The effects of increasing greenhouse gases on the long-term trends in the response of NLCs and the background atmosphere to the 11-year solar cycle, which spans 170 years (from 1849 to 2019) and covers 15 solar cycles, are also investigated. One of the main findings is that, in the presence of NLCs, the solar cycle response of water vapour strongly depends on altitude. The results show that the background H2O exhibit an apparent response to the solar cycle that increases after 1960 due to increased greenhouse gas concentrations.