Articles | Volume 8, issue 3
Atmos. Meas. Tech., 8, 1073–1087, 2015
Atmos. Meas. Tech., 8, 1073–1087, 2015
Research article
04 Mar 2015
Research article | 04 Mar 2015

Field-deployable diode-laser-based differential absorption lidar (DIAL) for profiling water vapor

S. M. Spuler1, K. S. Repasky2, B. Morley1, D. Moen2, M. Hayman1, and A. R. Nehrir3 S. M. Spuler et al.
  • 1National Center for Atmospheric Research, Earth Observing Lab, Boulder, CO 80307, USA
  • 2Montana State University, Electrical and Computer Engineering, Bozeman, MT 59717, USA
  • 3NASA Langley Research Center, Hampton, VA 23681, USA

Abstract. A field-deployable water vapor profiling instrument that builds on the foundation of the preceding generations of diode-laser-based differential absorption lidar (DIAL) laboratory prototypes was constructed and tested. Significant advances are discussed, including a unique shared telescope design that allows expansion of the outgoing beam for eye-safe operation with optomechanical and thermal stability; multistage optical filtering enabling measurement during daytime bright-cloud conditions; rapid spectral switching between the online and offline wavelengths enabling measurements during changing atmospheric conditions; and enhanced performance at lower ranges by the introduction of a new filter design and the addition of a wide field-of-view channel. Performance modeling, testing, and intercomparisons are performed and discussed. In general, the instrument has a 150 m range resolution with a 10 min temporal resolution; 1 min temporal resolution in the lowest 2 km of the atmosphere is demonstrated. The instrument is shown capable of autonomous long-term field operation – 50 days with a > 95% uptime – under a broad set of atmospheric conditions and potentially forms the basis for a ground-based network of eye-safe autonomous instruments needed for the atmospheric sciences research and forecasting communities.

Short summary
A water vapor lidar has been designed and tested which has the potential to enable a national-scale network. The system is low-maintenance, low-cost, eye-safe, and provides continuous profiles of water vapor with complete coverage, including periods of daytime bright clouds, from 300m above ground level to 4km with 150m nominal vertical resolution and 1 min temporal resolution. The sensor may be useful in improving our understanding of the distribution of atmospheric water vapor.