Derivation of wind fields from stratospheric trace gas observations

Kurzfassung

Within the ARISE project (Atmospheric dynamics Research InfraStructure in Europe), an inversion method for chemical tracers was developed based on the adjoint version of the SACADA-CTM (Synoptic Analysis of Chemical constituents by Advanced Data Assimilation - Chemical Transport Model). The method derives initial wind fields based on stratospheric trace gas observations. It is hoped that results can help to improve weather forecasting via chemical data assimilation. The SACADA-CTM is coupled to the German Weather Service GME global forecast system. SACADA-GME consists of a state-of-the-art chemical assimilation system covering stratospheric chemistry and dynamics. Using the adjoint of the tracer advection scheme with respect to observation-model increments (e.g., from satellite data) new initial wind fields can be derived. We investigate the system performance via twin experiments. With respect to real-world applications, we present results based on 6h inversions using realistic initial winds and MIPAS trace gas observations of O3, H2O, CH4 and N2O covering March 2003. The impact of trace gas selection and meteo conditions on results are discussed. Analyzed winds are evaluated by comparisons to independent data (e.g. LIDAR observations).