Injection height of biomass burning aerosols as seen from a spaceborne lidar

This paper analyzes new lidar measurements from space over regions of biomass burning activity. The height of the aerosol layers deduced from the lidar observations is compared to the mixing layer top diagnosed from numerical weather forecasts, to identify whether or not the aerosols are directly injected in the free troposphere. During July and August 2006, the best cases ( limited cloudiness, high density of fires) are found over South Africa and Northern Australia. Over these regions, the top of the aerosol layer is close to the mixing layer height, which is a strong indication that the aerosols are injected within the mixing layer. Other tropical areas with biomass burning activity are more difficult to interpret but the valid data support the same conclusion. For higher latitudes regions with biomass burning activity, although several aerosol plumes are identified above the mixing layer, most of the load is within the mixing layer. These observations made over a limited period and set of regions indicate that cases with pyro-convection and/or direct injection to the free troposphere are not frequent.