Analysis of Lidar Fields using Local Polynomial Regression

Torgny Lindström, Ulla Holst and Petter Weibring

Abstract:: Lidar (LIght Detection And Ranging) is a laser based tool for remote measurement of several atmospheric species of importance. We consider the analysis of a field, consisting of several consecutive measurements, in which the concentrations are proportional to the derivatives in the directions of the light paths. Inference is based on local polynomial kernel regression, both for estimation of the derivatives of the mean-function and for estimation of the variance-function. Bivariate bandwidth matrices are selected using the empirical-bias bandwidth selector (EBBS) adapted to allow for dependent data and to support selection of bivariate bandwidths. The estimation procedure is demonstrated on measurements of atomic mercury from the Solvay industries mercury cell chlor-alkali plant in Rosignano Solvay, Italy.

Key words:: Air pollution; heteroscedastic observations; local bandwidth selection; nonparametric; spatial dependence; variance-function estimation.