The effect of radial velocity gridding artifacts on variationally retrieved vertical velocities

Scott Collis (1) , Alain Protat (1, 2) , Kao-Shen Chung (3)

1 CAWCR - Centre for Australian Weather and Climate Research
2 SPACE - LATMOS
3 Department of Atmospheric and Oceanic Sciences [Montréal]

This article investigates the source and impact of artifacts produced by ordered linear interpolation techniques on variationally retrieved updraft intensities. Qualitative reasoning for the generation of periodic perturbations in gridded products is presented and a simple analytical investigation into the impact of gridding artifacts on updraft retrieval is carried out. By projecting a non-convergent flow typical of Darwin, Australia, onto the viewing geometry of a scanning radar a numerical assessment of the impact of gridding artifacts is carried out. A simple enhancement to ordered linear interpolation, Mixed ordered linear interpolation, is proposed to reduce gridding artifacts. Radial velocity grids produced using both techniques are used to investigate the generation of spurious updrafts with the simple ordered linear interpolation technique producing erroneous updrafts on the order of 2 ms−1. To investigate the impact on vertical velocities retrieved from a real weather event radar derived measurements taken during the active monsoon phase of Tropical Warm Pool International Cloud Experiment are gridded using both techniques and vertical velocities are retrieved and contrasted.

Domaines: Météorologie; Traitement du signal et de l'image [eess.SP]; Traitement du signal et de l'image [eess.SP]

Scott Collis, Alain Protat, Kao-Shen Chung. The effect of radial velocity gridding artifacts on variationally retrieved vertical velocities. Journal of Atmospheric and Oceanic Technology, 2010, 27 (7), pp.1239-1246. ⟨10.1175/2010JTECHA1402.1⟩. ⟨hal-00477211⟩