Details

Autor(en) / Beteiligte

• Polavarapu, Saroja
• Pulido, Manuel
• Park, Seon Ki
• Xu, Liang

Titel

Stratospheric and Mesospheric Data Assimilation: The Role of Middle Atmospheric Dynamics

Ist Teil von

• Data Assimilation for Atmospheric, Oceanic and Hydrologic Applications (Vol. III), 2017, p.429-454

Ort / Verlag

Switzerland: Springer International Publishing AG

Erscheinungsjahr

2017

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The middle atmosphere refers to the stratosphere and mesosphere and features dynamics and circulations that are fundamentally different from those of the troposphere. The large-scale meridional circulations in the middle atmosphere operate on seasonal and longer time scales and are largely forced by the breaking of upward propagating waves. The winter stratosphere is dominated by large-scale waves and a polar vortex which confines constituents and which is sometimes punctuated by stratospheric sudden warmings. In contrast, the summer stratosphere is quiescent. Meanwhile, the meridional circulation in the mesosphere is mainly driven by the breaking of a broad spectrum of gravity waves that have propagated upward from the troposphere. These facets of middle atmosphere dynamics have implications for, and pose unique challenges to, data assimilation systems whose models encompass this region of the atmosphere. In this work, we provide an overview of middle atmosphere data assimilation in the context of the dynamics of this region. The purpose is to demonstrate how the dynamics can be used to explain the behavior of data assimilation systems in the middle atmosphere, and also to identify challenges in assimilating measurements from this region of the atmosphere. There are two overarching themes. Firstly, we consider the vertical propagation of information through waves, resolved and parameterized, and Background error covariances. Secondly, we delve into the dynamical sources of model errors and techniques for their estimation.