Dynamics and Coupling Processes (Feb-2017)

 

DC1: Investigations on Horizontal and Vertical Couplings of Earth’s Atmosphere

Supervisors: Fazlul Laskar, Maosheng He, Prof. Jorge L. Chau

The primary energy to Earth comes from the incoming solar radiation. This solar input generates secondary processes like heating, cooling, circulation, etc., which produce oscillations in measurable atmospheric parameters. Such oscillations are often known as atmospheric waves. Depending on background conditions these waves can couple the atmosphere even from bottom to top and also from pole to pole. We shall investigate these couplings during different seasons and geophysical variability, as well as at different latitudes and longitudes. Special emphasis will be devoted to Sudden Stratospheric Warming events and Summer/Winter Winter/Summer transition periods. The investigation will be carried out primarily with the use of mesospheric winds obtained with radars, complemented with other ground-based systems, satellite measurements, reanalysis data, and whole atmosphere models.

 

DC2: Atmospheric tides and their impact on MLT-ionosphere coupling

Supervisors: Dimitry Pokhotelov, Maosheng He, Prof. Jorge L. Chau

Atmospheric tides are caused by a combination of solar heating and gravitational effects from the Sun and Moon. Propagating upwards, tides produce some of the most prominent perturbations in the mesosphere and lower thermosphere (MLT) region. . Interacting with the mean atmospheric flow and/or with shorter gravity waves, the tides can be amplified, impacting the MLT region on a global scale and affecting the ionosphere via an electromagnetic dynamo effect. To quantify the parameters of tides, the selected candidate will gain expertise in the analysis of high-performance computer simulations using global atmospheric circulation models and will perform the comparison with existing ground datasets from radars, lidars, airglow imagers, etc., as well as from satellite-based measurements. The work will involve extensive collaborations within IAP and with international partners, namely, the US National Center for Atmospheric Research. Further analyses will be done using ground and spaced-born observations of the ionospheric electron content and the thermospheric neutral density. The project is expected to lead to improved capabilities in understanding/forecasting the ionospheric space weather.

 

DC3: Gravity waves in the troposphere and mesosphere

Supervisors: Gunter Stober, Ralph Latteck, Prof. Jorge L. Chau

Gravity waves (GW) play an important role for the energy balance of the whole atmosphere because they carry energy and momentum from their source regions to the places where they dissipate. One source of GWs is the tropospheric synoptic weather pattern (e.g., tropospheric jets, convective clouds, etc.). The Middle Atmosphere Alomar Radar System (MAARSY) observes tropospheric winds with high spatial and temporal resolution in the altitude range of 3-22 km. The suitable candidate will investigate the excitation of GW due to tropospheric jets and the resulting momentum flux. Similar gravity wave analyses can be extended to the summer mesosphere where strong echoes are present which can be used as tracers.