The ILRC conferences are the internationally recognized forum for discussing all aspects of laser remote sensing. The program committee invites the traditional participants and all others from related fields to submit papers on recent advancements in lidar technologies and methods, and on applications for the understanding and modeling of the atmosphere, oceans, earth issues, and space exploration. Although ILRC21 will make ample room for reporting the latest innovations in the lidar science, the program committee wishes to emphasize the benefits that we can now reap from applications.

Long-term and wide-area measurement projects have begun to produce results of increasing relevance for measuring and modeling the natural atmosphere and the influence of human activities on our environment. To foster future developments in this direction, ILRC21 wants to hear about those projects, their achievements to date and the promises of the on-going research. Another important initiative of recent years has been the formation of national and international lidar networks to enhance our knowledge of transport processes and seasonal evolution of many atmospheric parameters. ILRC21 wishes to be the forum for discussing the results obtained thus far and for planning or coordinating future cooperation. Furthermore, spaceborne global lidar observations are becoming a reality and, interestingly, it is accomplished with a high degree of international collaboration. The ILRC21 program committee solicits papers that will describe what has been accomplished thus far, and expose the science and application aspects of these programs to encourage sharing by the entire community of the results, the challenges and the search for solutions. Finally, all these coordinated long-term applications are the result of numerous past contributions by individual groups. The ILRCs have played a unique role in disseminating their work. This ILRC remains committed to this goal and is, therefore, inviting papers on innovative lidar technologies and methods, on new retrieval techniques and applications, and on the development of turnkey friendly miniature systems.