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In order to get detailed vertical ozone profiles above the range of standard electrochemical ozonesondes (typically 35 km), a radiosonde together with an optical ozonesensor is launchend with a special plastic foliage balloon. The balloon payload consists of a digital radiosonde (DFM 90) using GPS for altitude measurements and a two channel filter spectrometer (optical sensor) to measure the vertical ozone distribution up to more than 40 km altitude. The ozone profiles obtained by the optical sensors will be compared with ground-based microwave and lidar ozone observations as well as with the standard balloon-borne ozone measurements with electrochemical ozone sensors.
The current scientific knowledge does not allow estimating accurately the surface radiative forcing caused by tropospheric aerosols and their influence on the evolution of the Earth climate. The radiative forcing depends on the optical properties of the aerosols at solar and thermal infrared wavelengths. These optical properties depend, in turn, on the chemical composition and size of the aerosols. Remote sensing with passive radiation sensors operating in the above-mentioned spectral ranges allows to measure the optical properties of the aerosols and to characterise their temporal variability. These data are needed for regional climate simulations of the Arctic, particularly for delineating the impact of the Arctic haze phenomenon. In this project, a synergetic effort will be made to obtain information about the radiative and microphysical properties of springtime arctic aerosols. Therefore, a polarisation-spectrometer for the solar spectral range, which is currently developed at the Free University of Berlin as a variant of the FUBISS spectrometer, will be operated from the surface in coincidence with the Fourier Transform InfraRed-spectrometer (FTIR) installed at Ny-Aalesund by the AWI. The former instrument measures the intensity and polarisation of the scattered solar radiation from the visible to the near-infrared. The latter measures the radiation emitted by the Atmosphere itself in the thermal infrared window region. Together, they thus provide a wealth of information about the aerosol optical properties at the interesting wavelengths (spectral optical depth, single-scattering albedo, and asymmetry factor of the phase function), which will allow inferring the aerosol microphysical properties. Complementary measurements of the aerosol microphysical properties will be provided by an aerosol volatility analyser, which is maintained by the University of Leeds and will also be brought to Ny-Aalesund. This instrument comprises a fast response scanning volatility system and an optical particle counter. From the thermal response of the aerosol number and the change in the size distribution conclusions can be inferred about the chemical composition and the state of mixing of aerosols as a function of size.
The aim of the project is to perform solar and lunar absorption measurements of atmospheric trace gases for the valdation of the SCIAMACHY satellite. Besides the routine observations within the NDSC it is planned to perform more intense measurements, especially during the satellite overpasses.
Situated in the Arctic Ocean the planetary boundary layer over Ny Ålesund is dominated by marine aerosols. Hight and time variation of boundary layer aerosols are examined with the tropospheric lidar system in Ny Ålesund. To determine the aerosol and its optical properties more exactly information from more wavelenghts are necessary as the sun-photometer at the Koldewey Station can provide. First combined evaluation of photometer and LIDAR data during the ASTAR-campaign in spring 2000 demonstrated feasibility and advantages of this method for the free troposphere. Furthermore this method is to be applied on boundary layer aerosol to research also its optical properties.
A tropospheric lidar system with a Nd:YAG-Laser was installed at the Koldewey-Station in 1998. It operates at a laser wavelengths of 355, 532, and 1064 nm with detection at 532 nm polarised and depolarised, and at Raman wavelengths like 607nm (nitrogen). It records profiles of aerosol content, aerosol depolarisation and aerosol extinction. During polar night the profils reach from the ground up to the tropopause level, while during polar day background light reduces the altitude range. The main goal of the investigations is to determine the climate impact of arctic aerosol. Analysis of the climate impact will be performed by a high resolution regional model run at the Alfred Wegener Institute (HIRHAM). The lidar system is capable to obtain water vapour profiles in the troposphere. Water vapour profiles are crucial for the understanding of the formation of aerosols. The water vapour profiles are also used for the validation of profiles measured by the CHAMP satellite from 2001 onwards.