Method to Determine PBL Height and Various Layers within Troposphere, as Measured by a Lidar System

The gradient method is applied to the total recorded backscatter signal (including the background) multiplied by squared range and divided by molecular backscatter coefficient and molecular transmission terms (known). Thus, the new function has a linear dependence on squared range divided by molecular backscatter and molecular transmission terms. On a 2 dimensional plot, as a function of time and range (altitude here), for each time stamp, the intercept corresponding to the derivative of the new function is determined. The mean and the standard deviation (STD) of the intercept, calculated from the derivative of the function over the far-end region (12-15km) are computed. Next, the heights where the corresponding intercepts are outside the limits defined by mean +/- 1 STD are selected. Thus, intercepts larger than the mean + 1 STD represent regions of decreasing back-scatter signal and intercepts smaller than mean - 1 STD represent regions of increasing backscatter sig-nal. In the second step of the algorithm, the planetary boundary layer (PBL) height and the delimitation of pollution layers or clouds are determined. For the layers/clouds cases, the layers/clouds can be also quantified in terms of increasing and decreasing regions. Comparisons with the gradient method and wavelet technique, applied to RCS will be shown during conference.JRC.DDG.H.2-Climate chang