Detection of Mesoscale Pressure Perturbations with Five Minute Gridded Analyses

Large magnitude short-term pressure perturbations are produced by atmospheric phenomena such as gravity waves and mesoscale convective systems. The large spatial gradients produced by these perturbations may result in enhanced, sometimes damaging, surface winds. While much progress has been made to improve numerical guidance to better assess mesoscale features, numerical forecasts often imperfectly capture their location and strength. This work improves on the conventional hourly temporal resolution of most gridded numerical data sets by utilizing high frequency pressure observations to better assess the detection and translation of mesoscale features.

Hourly Real Time Mesoscale Analysis (RTMA) surface pressure grids were acquired for the 1 March – 31 August 2011 period. During this period, the USArray Transportable Array (TA) suite of pressure sensor platforms was deployed in a Cartesian-like grid (about 70 km spacing) across the central United States. Atmospheric pressure data, at 1 Hz temporal resolution, was collected for each station. The RTMA grids and TA observations were blended using two dimensional variational techniques to produce gridded surface pressure analyses every 5 minutes for the period examined. Prominent mesoscale pressure perturbations were determined through temporal band-pass filtering (10 min - 12 h) of the analysis grids and prominent pressure perturbations are detected and tracked. Examples of case events are shown as well as statistics for all detected perturbations.