Ensemble filtering using a 3d chemical-dynamical middle atmosphere model

Tomoko Matsuo, GSP post doc

The mesosphere and lower thermosphere (MLT) region is a transition region where wave energy originating from the troposphere and stratosphere dissipates and is absorbed via dynamical, chemical, and radiative processes, and its energetics and dynamics further affects the upper thermosphere where the interactions between plasma and neutral species become important. Recently launched Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) spacecraft, together with a network of ground-based observation sites, provides an unprecedented set of comprehensive global measurements of the region.

With the NCAR Data Assimilation Research Testbed (DART) facility, a prototype ensemble filter assimilation system for synthetic observations using a 3-d chemical dynamical middle atmosphere model is being constructed. Compared to the synoptic meteorological system in the troposphere, the MLT region is significantly more dissipative and strongly forced. We will discuss how an ensemble data assimilation problem can be formulated in such a system especially when the model does not exhibit natural error growth.

*(in collaboration with Jeffrey Anderson, Dan Marsh, and Anne Smith)