Correction scheme for experimental biases in differential absorption lidar tropospheric ozone measurements based on the analysis of shot per shot data samples

From lidar signals detected with a shot per shot differential absorption lidar instrument tuned for tropospheric ozone measurements and recording each individual return, we reconstruct histograms of their sampled values fbr each channel of our digitizers. The analysis of their shape permits the correction of our measurements for experimental biases. In particular, a negative correlation is found between the skew of the histograms and the intensity of the backscattered light. The skew comes from a tail at high sampled values, interpreted as due to a raise of the relative contribution to the signal of a signal-induced noise when this intensity diminishes. By fitting a Gaussian function to the histograms without considering their tails, we calculate average signals unbiased by the corresponding noise. This approach allows us to increase the range of our ozone profiles, up to as much as double it in some cases. (C) 1997 Optical Society of America.