Capabilities and Benefits of Coherent Doppler LIDARs for Future Weather Observing Networks

The number and quality of atmospheric observations used by numerical weather prediction modelers, meteorologists and forecasters is increasing year after year and yet, the ability to consistently achieve statistically significant increases in forecast skill remains challenging, even within the most resolved numerical models. While numbers of contributing factors involving these challenges have been identified including the difficulty in accurately establishing initial conditions, improving the observations at regional and local scales is required for maintaining skillful high resolution numerical models (below 2km) which require observations of non-synoptic winds. Above the uncertainty of weather forecasts, the goal is also to improve the detection of severe and extreme weather events (severe thunderstorms, tornadoes and other mesoscale phenomena) that can adversely affect life, property and commerce, primarily in densely populated urban centers. This paper will study the potential use of Coherent Doppler LIDARs as profilers or as scanning sensors, to cover regional and local areas of interest. Firstly, the intrinsic performances of Doppler LIDARs will be presented: data availability within various weather conditions, measurement range, and accuracy of wind measurements. As shown in Figure 1, the measurement range of a Coherent Doppler LIDAR varies with weather conditions, primarily visibility (atmospheric attenuation of light) and rain rate. In addition, the technical siting constraints of LIDARs will be presented in the case of the building of a network of LIDARs, as well as the operational use of LIDAR data. Considering a particular region, the paper will propose a methodology of establishing a network of LIDARs given the current uncertainty of numerical forecasts, and regional and local effects (orography, meteorological events linked to the localization, exposure).The paper will subsequently describe the use of Scanning LIDARs during a series of trials to better monitor severe storms and wind hazards. As a final perspective, the paper will highlight the benefits of Scanning LIDARs for operational and local weather observing networks for use in numerical weather prediction modelling techniques, in situ observation or forecasting initiatives. Figure1. Permanent installation of a WINDCUBE400S LIDAR on a roof in the suburbs of Paris (left) and Unfiltered (line) and filtered (dash line) statistical ranges obtained (right).