Lagrangian Methods for Climatological Analysis of Regional Atmospheric Transport

Abstract

A quantitative climatological analysis of regional-scale atmospheric transport in Texas is developed using previously described Lagrangian (kinematic) trajectory methods. The trajectories are computed using resolved winds from 1979 to 2001 from the National Centers for Environmental Prediction?National Center for Atmospheric Research reanalysis project dataset. The wind data do not include small-scale turbulent atmospheric motion. The probability distributions of particle trajectories can be used to estimate the climatological (ensemble mean) Green's function for the mass conservation equation for a passive trace substance. A discrete approximation of the Green's function is computed for low-level summertime atmospheric flow over Texas. Examples are provided of the use of the Green's function to estimate both forward and backward transport properties. The Green's function can be used to evaluate the climatological probability of transport by the resolved flow to or from a given location.