As part of this network, about thirty groundbased Lidar (Light Detection And Ranging) instruments deployed worldwide from Pole to Pole are monitoring atmospheric ozone, temperature, aerosols, water vapour, and polar stratospheric clouds. This laser-based active remote sensing technique has been used widely for several decades in environmental science and chemistry, and has contributed significantly to the validation of space-based measurements.
While the NDACC remains committed to monitoring changes in the stratosphere with an emphasis on the long-term evolution of the ozone layer, its priorities have broadened considerably to encompass issues such as the detection of trends in overall atmospheric composition and understanding their impacts on the stratosphere and troposphere, and establishing links between climate change and atmospheric composition.
To ensure quality and consistency of the NDACC lidars operation and products, a number of protocols have been formulated covering such topics as validation, measurements and instruments intercomparisons, and theory and analysis. The members of the NDACC Lidar Working Group (LWG) are committed to follow the principles of these protocols, and the LWG meets every two years to review and coordinate the activities necessary to the valuable contribution of the lidars to NDACC.