The Global NO-Distribution Computed on the Basis of a Dynamic 3D-Model and Implications on the Winter Anomaly of the D-Layer

Abstract The winter anomaly of the electron density of the D-layer is tightly connected with the increase of the NO concentration within the lower thermosphere and upper mesosphere. Beside a general enhancement of the electron density in moderate and higher latitudes, the phases of excessively enhanced electron density are characteristic of the winter anomaly. On the basis of a three-dimensional dynamic model of the photochemistry of the mesosphere and lower thermosphere the global NO distribution has been investigated besides the distribution of the relevant trace and plasma constituents. The model connects the Cologne three-dimensional dynamic grid point model with a photochemical model. 10 constituents and chemical families submitted to transport have been regarded and additionally 15 further chemical and plasma species. The model experiments show that especially the pattern of the vertical wind creates the pattern of the enhanced NO concentration. Results of model runs are presented and discussed.