Norway: projects/activities

The Norwegian Radiation Protection Authority is responsible for a network of 5 air filter stations. These collect air samples through high density filters which are analyzed weekly by gamma spectroscopy. The network was established in the early 80s and is continuously updated. The purpose of the network is to assess the levels and composition of emissions from incidents and accidents. In addition, with the help of meteorological data, possible sources of release may be identified.

The project EPOPEE is embedded in the international project ASTAR to study direct and indirect climate effects of aerosols and clouds in the Arctic. The particular goals of the project EPOPEE are to experimentally characterize the ice phase in Arctic clouds (including the ice phase) in situ, to study the aerosol-cloud as well as cloud-radiation interactions, and to develop adequate methods to validate remote sensing cloud parameters. In 2004 the project EPOPEE is mainly organized around in situ observations of detailed microphysical and optical cloud properties onboard the Polar-2 aircraft during the transition from polluted Arctic haze (observed especially in late winter, early spring months) to clean summer aerosol conditions. The transition from Arctic haze to clean summer conditions is quite sharp (a large amount of aerosols coming from Eurasian industrial areas accumulate over the Arctic and cover the Arctic by a layer of a smog-like haze of the size of the continent of Africa) due to a radical change in atmospheric transport patterns and is, thus, easy to identify. During Arctic summer, the high latitudes are then more or less “protected” from long-range transport of air masses from lower latitudes. The principal scientific objective of the project EPOPEE in 2004 will focus on studying the aerosol-cloud interactions with particular attention given to the ice phase nucleation in Arctic mixed-phase clouds. The interpretation of the instrumental observations will broadly benefit from a very close cooperation with the LaMP modelling group for theoretically coupling small-scale processes (cloud particle nucleation) with meso-scale dynamics. Furthermore, the project will focus on cloud-radiation interaction and the development of adequate methods to validate cloud parameters retrieved from remote sensing techniques. Therein, we will experimentally answer the question of how the different ice crystal shapes govern the scattering phase function of respective crystals. Moreover, the in situ cloud measurements will allow to develop an adequate strategy for the interpretation of remote sensing data from a depolarisation Lidar onboard the same aircraft (Polar-2).

Observation of proton aurora on the dayside with use of spectrometer operated simultaneous in Longyearbyen and Ny-Ålesund. Absolute calibration of the instrument located at The Sverdrupstation were performed in the period 9-13 January 2003.

Objective 1: Proof of the possibility to estimate temperatures from meteor decay times using co-located, simultaneous meteor observations on two, well separated frequencies (32.55 MHz/SKiYMET radar and 53.5 MHz/ALWIN MST radar) without the assumption of a predetermined temperature gradient. The second method for determining temperature height profiles uses the direct measurement of the ambipolar diffusion coefficient in conjunction with pressure data to estimate temperatures. Pressure data from empirical models are often too unreliable, therefore pressure data derived from rocket-borne falling spheres measurements could be used for a reliable temperature determination. Objective 2: Proof of the method using co-located meteor radar measurements and falling sphere soundings conducted in 2002 at Andenes (69N) during the MaCWAVE campaign. It should be possible to estimate meteor temperature profiles in a height range between 82 km and about 94 km.

Polar stratospheric clouds play a key-role in polar ozone destruction. Cold temperatures in the vortex allow formation of these clouds. Depending on the PSC-type different formation-temperatures have to be reached. Synoptic temperatures do not always fall to these formation-temperatures, but waves in the atmosphere can lead to additional cooling of several 10 K, which allows PSC-formation. Whereas the wave-activity at the ESRANGE is very high due to hilly surrounding area, the orographic wave-activity at ALOMAR is expected to be rather small. Waves with long wavelengths will be present at both stations simultaneously. Coordinated measurements of temperature and aerosols will show both the large-scale wave-part and also the locally induced wave-part. Such measurements should allow identification of the different wavelngth scales and in addition contribute to a better estimate of the importance of wave-induced clouds for PSC-formation.

During the past years, atmospheric research in high latitudes has been focussed on processes causing ozone loss in the polar winter lower stratosphere1). Recent research efforts also dealt with regions up to the lower mesosphere, and studied the effects of charged particle precipitation on NO and ozone2)-5). However, the measurement techniques and hence the database for studying such processes in this altitude range are very limited. The Airborne SUbmillimeter Radiometer ASUR6),7) of the Institute of Environmental Physics of the University of Bremen has recently been equipped with a high-resolution spectrometer that will enable the retrieval of vertical profiles of ozone up to an altitude of about 65 - 70 km. Its measurement capabilities comprise also several other species of interest, especially NO. This makes the measurement technique particularly suitable for upper stratospheric/lower mesospheric studies. The lidar at ALOMAR is capable of measuring highly resolved vertical profiles of ozone up to an altitude of 60 km, thus giving the rare opportunity for intercomparison and validation studies in an altitude range reaching from the lower stratosphere to the lower mesosphere. Therefore we propose to perform simultaneous ozone measurements of the ASUR instrument with the ALOMAR lidar, supported by launches of ozone sondes.

The upper troposphere and lower stratosphere are strongly affected by the appearance of gravity waves with different scales. Due to the exponential decrease of the density with the altitude, the upward propagation of these waves is associated with an increase in their amplitudes. Associated with the wave breaking and with deposit of momentum and energy in the background flow, the dynamical and thermal structure at upper stratospheric and mesospheric heights are essentially influenced. However, their sources and the quantitative aspects of these processes are poorly understood at present. Here we are focussing on the investigation of long periodic gravity waves with periods of several hours and horizontal wavelengths of more than hundred kilometres. In contrast to the pure internal gravity waves, these waves are called inertio-gravity waves due to their influence by the rotation of the Earth, described by the Coriolis effect or by the inertial frequency.

Noctilucent clouds (NLC) remain a fascinating phenomenon of the upper atmosphere to study. The questions about the typical particle density and particle size distribution within a NLC are very prominent ones, to which a number of answers have been given, though some of the answers contradict each other. The parameters of particle size distributions can be derived from groundbased lidar measurements of the spectral dependence of the volume backscatter coefficient of an NLC. Such studies have been performed during a number of NLC events by e.g. the ALOMAR Rayleigh/Mie/Raman (RMR) lidar (von Cossart et al., GRL, 26, 1513, 1999). A drawback of these experiments is the wavelength limitation of the RMR lidar, the shortest wavelength of which is 355 nm. At this wavelength, the sensitivity of the lidar to particles with sizes smaller than, say, 25 nm is minimal. Because a considerable part of the entire particle population may have sizes below that threshold, a lingering question remains whether or not this drawback matters for typical NLC distributions. Using the ALOMAR ozone lidar, a measurement of the NLC volume backscatter coefficient at 308 nm becomes possible. Due to the l-4 -dependence of the backscatter coefficients, the latter are almost a factor of 2 larger at this wavelength than at 355 nm. For this reason and in order to gain a fourth wavelength to the spectral distribution, we aim at using the ozone lidar for the outlined project.

Waves play a major role for the momentum and energy transport in the middle atmosphere [Fritts and van Zandt, 1993] by modifying the local temperature field as well as the general circulation when the waves reach the saturation level and break [Holton, 1983; Fritts, 1984]. The MACWAVE rocket campaign is investigating the wave field in polar latitudes during summer and winter. To learn more about the horizontal structure of the wave field, it is important to measure at more than one station. For the monitoring of the vertical transport by the waves, measurements over a large height range are necessary. The combination of lidars, radiosondes and falling spheres will cover the region from the ground up to approximately 105 km. When comparing data, it is important to take into account the different measurement principles and integration times. The rocket will show small scale variations whereas the lidar permits a continuous monitoring of the temperature and wave situation

The purpose of the CHAOS_A project is to perform measurements under "Antarctic conditions" during the polar vortex period with the new assembled spectrometer in order to perform tasks that cannot be achieved at low latitudes namely OClO detection. Therefore the campaign focus more in technical aspects than scientific ones. The period of observation may be short to achieve results of scientific interest and those will depend on the meteorology of the stratosphere (position of the polar vortex relative to the station, temperatures at the lower stratosphere, etc). The OClO results will be compared with those obtained by the NILU (Andoya) and Heidelberg U.

Monitoring solar wind-magnetosphere-ionosphere coupling processes from the aurora.

The general objective of the proposed project is to increase the understanding of the Mercury Depetion Events occoring in the Arctic sunrise and quntify the input of mercury to polar ecosystems during this events.

Permanent monitoring of basic climate data for the purpose of better understanding the Arctic climate processes and detecting trends.