Geographical variations in the vertical structure of geo- potential height fluctuations.

Abstract

Temporal (but nonseasonal) fluctuations in the geopotential height field exhibit large regional contrasts in vertical structure, as manifested in the geographical distributions of the correlation between 1000 and 500 mb height, and the ratio of the amplitudes of the fluctuations at those levels. This geographical variability is investigated in order to ascertain its seasonal, frequency and zonal wavenumber dependence and its relation to other indicators of vertical structure: statistics involving the 1000-500 mb thickness, and the structure of the dominant mode in an eigenvector analysis expansion of geopotential height in the vertical. Results are based on operational analyses by the US National Meteorological Center over a 15 year period. The implications of these results on the design of observing networks and objective analysis procedures are discussed. -from Authors