SPATIAL-RESOLUTION OF A TRANSPORT INVERSION TECHNIQUE

A spatial calibration for conditional frequency analysis, the inversio n technique applied to routine back trajectories to study the associat ion between geographical regions and conditions at a receptor, is disc ussed for trajectories arriving at Hopi Point, Arizona. Several 0.5 de grees x 0.5 degrees cells were selected at three different distances f rom Hopi Point; These cells were used to mimic sources, with air resid ing over them considered contaminated by imaginary emissions, The dist ribution of back trajectory segment endpoints over a latitude-longitud e grid was then examined as a function of the trajectories sojourn ove r each imaginary source cell on their way to the receptor. The areal e xtent of significant associations, evaluated for different seasons and the various ideal source positions, suggests that this inversion tech nique can resolve the direction of potential sources but has limited r esolution for their radial distance from the receptor.