Probing Aerosol Layers over the Santiago Valley in Central Chile with Fixed and Moving Ceilometers

Lidar ceilometers have become very useful instruments to characterize aerosol layers present in the atmospheric boundary layer (ABL) under polluted conditions. As such, they not only provide information on pollution relative levels, but they also inform on the dynamics of the ABL. The Santiago valley in central Chile, provides an ideal case for such applications due to its high load of aerosols, especially during air pollution episodes occurring in the cold season. A CL31 ceilometer operating in downtown Santiago since 2007 has been used in the past to derive a climatology of daytime ABL depths (Muñoz and Undurraga, 2010) and to describe the complex dynamics of the evening transition of the Santiago ABL (Muñoz and Alcafuz, 2012). Recently, four additional ceilometers have been installed in the valley. Additionally, during short-term campaigns in 2023, a ceilometer was mounted on the pickup of a truck, and several transects were performed over the city. These new measurements provide new information on the horizontal variability of aerosol layers in the valley, which is presented in this work.