Development of a multiwavelength aerosol and water-vapor lidar at the Jungfraujoch Alpine Station (3580 m above sea level) in Switzerland

Abstract

The Jungfraujoch Research Station (46.55 degrees N, 7.98 degrees E, 3580 m above sea level) for decades has contributed in a significant manner to the systematic observation of the Earth's atmosphere both with in situ measurements and with trace gas column detection. We report on the development of a lidar system that improves the measurement potential of highly resolved atmospheric parameters in both time and space, with the goal of achieving long-term monitoring of atmospheric aerosol optical properties and water-vapor content. From the simultaneously detected elastic-backscatter signals at 355, 532, and 1064 nm, Raman signals from nitrogen at 387 and 607 nm, and water vapor at 408 nm, the aerosol extinction and backscatter coefficients at three wavelengths and a water-vapor mixing ratio are derived. Additional information about particle shape is obtained by depolarization measurements at 532 nm. Water-vapor measurements by use of both nitrogen and water-vapor Raman returns from the 355-nm laser beam are demonstrated with a vertical range resolution of 75 m and an integration time of 2 h. The comparison to the water-vapor profile derived from balloon measurements (Snow White technique) showed excellent agreement. The system design and the results obtained by its operation are reported.