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An inclined lidar with vertical resolution of 0.4 m was used for detailed boundary layer studies and to link observations at Zeppelin Mountain (474 m) and Ny-Ålesund, Svalbard. We report on the observation of aerosol layers directly above the Kongsfjord. On 29 April 2007, a layer of enhanced backscatter was observed in the lowest 25 m above the open water surface. The low depolarization ratio indicated spherical particles. In the afternoon, this layer disappeared. The ultrafine particle concentration at Zeppelin and Corbel station (close to the Kongsfjord) was low. On 1 May 2007, a drying process in the boundary layer was observed. In the morning, the atmosphere up to Zeppelin Mountain showed enhanced values of the backscatter coefficient. Around noon, the top of the highly reflecting boundary layer decreased from 350 to 250 m. The top of the boundary layer observed by lidar was confirmed by radiosonde data. [ABSTRACT FROM AUTHOR]

We present data from two eddy covariance systems for determining the sensible and latent heat flux and the shear stress near the earth's surface. One measures continuously since September 2010 close to the village Ny-A° lesund, Svalbard, the other one was located on Kongsvegen glacier for a short period in April 2011. Two examples for small-scale variability are discussed: near surface external gravity waves associated with katabatic wind from the Broggerbreen glacier located a few kilometres southwestern of Ny-A° lesund, and an episode when the two eddy systems at the different measurement sites captured very different conditions at the same time. In case of gravity wave motion the eddy covariance method results in fictitious positive fluxes due to the strong correlation between temperature and vertical wind, which has to be considered carefully. The comparison between the two sites showed that generally the dynamical processes near the Earth's surface for Ny-A° lesund and the Kongsvegen glacier are different and local. But there are also cases of synchronization due to synoptic influences, and then the same processes are visible at the two measurement sites. Both examples show that the boundary layer in Ny-A° lesund is not only affected by the main glaciers in the east of the village, but also by other orographical characteristics and synoptic issues. Therefore, the only meaningful way to deal with point measurements is to consider them in context with the surrounding orography and the general meteorological conditions. [ABSTRACT FROM AUTHOR]

The potential of a new improved version of micropulse lidar (MPL-4) on polar stratospheric cloud (PSC) detection is evaluated in the Arctic over Ny-Ålesund (79°N, 12°E), Norway. The campaign took place from January to February 2007 in the frame of the International Polar Year (IPY) activities. Collocated Alfred Wegener Institute (AWI) Koldewey Aerosol Raman Lidar (KARL) devoted to long-term Arctic PSC monitoring is used for validation purposes. PSC detection is based on lidar retrievals of both backscattering ratio R and volume depolarization ratio δV. Two episodes were unequivocally attributed to PSCs: 21–22 January and 5–6 February 2007, showing a good correlation between MPL-4 and KARL backscattering ratio datasets (mean correlation coefficient = 0.92 ± 0.03). PSC layered structures were characterized for four observational periods coincident with KARL measurements. Also, PSC type classification was determined depending on the retrieved R and δV values as compared with those obtained by KARL long-term Arctic PSC measurements. Tropospheric cloud cover from lidar observations and both ECMWF potential vorticity and temperature at 475 K, in addition to temperature profiles from AWI daily radiosoundings, are also reported. Height-resolved and temporal evolution of both PSC episodes obtained from MPL-4 measurements clearly show that MPL-4 is a suitable instrument to provide long-term PSC statistic monitoring in polar regions. These results are the first reported on PSC detection in the Arctic by using a low-energy and highly pulsed lidar operating on autonomous and full-time continuous mode MPL-4. [ABSTRACT FROM AUTHOR]