Ground-based lidar measurements from Ny-Ålesund during ASTAR 2007

Abstract

Abstract. During the Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) in March and April 2007, measurements obtained at the AWIPEV Arctic Research Base in Ny-Ålesund, Spitsbergen at 78.9° N, 11.9° E (operated by the Alfred Wegener Institute for Polar and Marine Research – AWI and the Institut polaire français Paul-Emile Victor – IPEV), supported the airborne campaign. This included lidar data from the Koldewey Aerosol Raman Lidar (KARL) and the Micro Pulse Lidar (MPL), located in the atmospheric observatory as well as photometer data and the daily launched radiosonde. The MPL features nearly continuous measurements; the KARL was switched on whenever weather conditions allowed observations (145 h in 61 days). From 1 March to 30 April, 71 meteorological balloon soundings were performed and compared with the concurrent MPL measurements; photometer measurements are available from 18 March. For the KARL data, a statistical overview of particle detection based on their optical properties backscatter ratio and volume depolarization can be given. The altitudes of the occurrence of the named features (subvisible and visible ice and water as well as mixed-phase clouds, aerosol layers) as well as their dependence on different air mass origins are analyzed. Although the spring 2007 was characterized by rather clean conditions, diverse case studies of cloud and aerosol occurrence during March and April 2007 are presented in more detail, including temporal development and main optical properties as depolarization, backscatter and extinction coefficients. Links between air mass origins and optical properties can be presumed but need further evidence.

Springtime Arctic aerosol: Smoke versus haze, a case study for March 2008

“…The derived lidar ratios for this case are similar to values which were derived for Arctic Haze cases in 2007 (Hoffmann et al, 2009(Hoffmann, 2011. For the lower free troposphere typically values around 30 sre60 sr for 532 nm and 25e50 sr for 355 nm were found over Spitsbergen.…”

“…The value is around 4.4%. Similar to earlier findings in Ny-Ålesund for Arctic Haze (Ritter et al, 2004;Hoffmann et al, 2009) the aerosol is only slightly depolarizing and can, hence, be described with Mie theory in good approximation.…”

“…In 2008, the lidar consisted of a Spectra Pro 290 laser with 50 Hz and 10 W per color and a 30 cm recording telescope with a field of view (fov) of 0.83 mrad. More technical details and applications of this lidar can be found in Hoffmann et al (2009).…”

“…Ny-Ålesund provides a unique infrastructure for atmospheric research in the European Arctic with different scientific facilities, including lidar, sun and star photometer, a BSRN field and daily radio sounding. Some of the measurements are described in Hoffmann et al (2009).…”

Inclined lidar observations of boundary layer aerosol particles above the Kongsfjord, Svalbard

“…In this paper we present AMALi lidar data in the backscatter ratio quantity, defined as the ratio of the total backscatter coefficient (molecular Rayleigh scattering and aerosol scattering) to the molecular Rayleigh scattering coefficient. Typical values for backscatter ratios at the clean Arctic site Ny-Ålesund are around 1.1 to 1.2 for 532 nm wavelength (Hoffmann et al 2009). The initial evaluation of the lidar data was done with the standard Klett algorithm (Klett 1985).…”