Development of the GRUAN Lidar Programme: Proposed Guidelines, Recommendations and Integrated Framework for the Creation of GRUAN Lidar Products

The GCOS Reference Upper Air Network (GRUAN) has been producing temperature and water vapor profiles from RS92 Vaisala radiosondes measurements for several years with an improved and standardized characterization of the conditions of measurements and their uncertainty. Such datasets are essential to capture with improved confidence the long-term trends associated with climate change. Using the same philosophy, the GRUAN Task Team on Ancillary Measurements has been working towards the production of similar, well-characterized climate variable datasets using techniques other than radiosonde, namely lidar, microwave radiometry and Fourier Transform spectroscopy. The present work reviews the various incentives made in 2012/2013 for the development of a GRUAN Lidar Product. It reviews the proposed framework, tools, and standard operating procedures necessary for the production of lidar data compliant with GRUAN requirements and recommendations. Focus is made on the design of a so-called “GRUAN Lidar Programme”, which provides an integrated framework with the main components including: 1/ recommendations on instrumental design and standard operating procedures, 2/ a network-wide, standardized and comprehensive metadata recording system, and 3/ the centralized and consistent processing of the raw lidar data. The GRUAN lidar water vapor, temperature and ozone products will be optimized for multiple applications such as the detection of long-term variability and trends in the troposphere and stratosphere, the validation of other GRUAN and non-GRUAN sensors, case studies of various meteorological events (e.g., boundary layer changes, cold fronts, tropopause folds, troposphere/stratosphere exchanges, etc.), and the assimilation of the GRUAN lidar profiles by mechanistic, mesoscale, or operational models.