Projects/Activities

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Displaying: 41 - 60 of 99 Next
41. SKERRIES - stratospheric climatology by regular balloon-borne

Objective: to collect climatology information on the seasonal and year-to-tear variability of stratospheric CFCs, water vapour and atmospheric electrical parameters.

Atmospheric processes Geophysics Climate variability Spatial trends Climate change Arctic Atmosphere Temporal trends
42. Descartes

Objectives 1. To develop the measurement technique further, providing more accurate measurements and extend the method to a larger number of trace species 2. To monitor the presence of CFC:s and other longlived anthropogenic tracers in the stratosphere 3. To use long-lived anthropogenic species as tracers of atmospheric motion, in particular for comparison with atmospheric models Reserarchers: Descartes is a joint research programme currently involving N.R.P Harris and J.A. Pyle, Centre for Atmospheric Science at the Department of Chemistry, University of Cambridge, U.K., and Hans Nilsson and Johan Arvelius, Swedish Institute of Space Physics, Kiruna, Sweden

Atmospheric processes Ozone Geophysics Chlorofluorocarbons (CFC) Emissions Arctic Atmosphere Temporal trends
43. Fair Weather Atmospheric Electricity

The atmosphere carries a continuous electric current and , even during fair weather, there is a strong electrostatic electric field, up to 200 volts per meter, close to the ground. This electric current is thought to be due to the accumulated effect of thousands of thunderstorms, mostly in the tropical regions of the Earth. These storms feed a current from the ground up to the ionosphere, a highly conducting layer in the atmosphere which lies above about 70 km altitude. The current spreads out around the globe through this layer and returns to Earth through the atmosphere as the 'fair weather current' outside the thunderstorm areas. Objective: Investigation of the part of the Earths global electrical circuit: fair weather current and its interaction with geomagnetic phenomena, such as, for example, a magnetic substorms. We use the data of the air-earth current measured by a long wire antenna installed in Kiruna/Esrange, Sweden. In July 1999 we have installed a new portable antenna at a distance of about 30 km from the old one. This antenna has a length of nearly 50 m, and we are recording the near ground vertical current with a time resolution of 10 seconds. The data from both instruments will be analysed together - for comparison and possible separation of the meteorological effects.

Atmospheric processes Air-Earth current Geophysics Climate variability Arctic
44. Long-Term and Solar Variability effects in the Upper Atmosphere

Objective: to determine how solar activity influences temperatures, winds, electric currents and minor constituents and to allow possible anthropogenic influences to be determined. Uses primarily measurements by the ESRAD and EISCAT radars, plus ground-based and balloon-borne measurements of atmospheric electric fields and currents.

Atmospheric processes Noctilucent clouds Geophysics Climate variability Solar Proton Events Climate Climate change Modelling Emissions Arctic Atmosphere Polar mesospheric summer echoes (PMSE) Temporal trends
45. Protoniks

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.

Atmospheric processes Geophysics Atmosphere
46. Lidar Measurements, valley - mountaintop

documentation and monitoring of the aerosol content of a mountain valley atmosphere and its diurnal changes

Atmospheric processes Climate variability Emissions Atmosphere
47. Aerosol and Trace Gas Measurements at Sonnblick

For a two year period daily samples of selected trace gases (nitric acid, sulfur dioxide and ammonia) and aerosol compounds (sulfate, nitrate, oxalate and ammonium) are determined with filter packs at the Sonnblick Observatory. The measurements will be used to identify the seasonal cycles of the selected trace gases and aerosol compounds at the 3 km level above Central Europe. Especially during the cold season previous measurements showed that samples collected at the Observatory represent free tropospheric air masses. Together with wet deposition measurements carried out at the site scavenging parameters are calculated.

Atmospheric processes Acidification Atmosphere
48. Estimation of temperatures in the upper mesosphere using meteor decay times observed on 32.55 MHz and 53.5 MHz

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.

Radar Atmospheric processes Geophysics Arctic Atmosphere temperature
49. Simultaneous Measurements of Temperatures, Waves, and PSCs in the Polar Winter-Stratosphere on both Sides of the Scandinavian Mountains

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.

PSC Atmospheric processes Ozone Climate variability Climate temperature profiles Atmosphere wave-activity
50. Stratosphere-mesosphere intercomparison of ozone profil

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.

Atmospheric processes Ozone Geophysics radiometer Climate Arctic Atmosphere lidar
51. Investigation of long periodic gravity waves and their possible sources in the vicinity of the Scandinavian mountain ridge

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.

Atmospheric processes Geophysics ozon-profile Modelling Arctic temperature-profiles Atmosphere wind
52. Ground-based observations of noctilucent clouds With the shortest possible wavelength (308 nm)

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.

Atmospheric processes Climate NLC Arctic Atmosphere lidar
53. Simultaneous multi-instrumental measurements of temperatures, waves and PSCs in the polar winter atmosphere on both sides of the Scandinavian mountains

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

Atmospheric processes Ozone Geophysics Climate change Arctic Atmosphere
54. CHAracterisation of OClO Spectrometer for Antarctica: Evaluation measurements inside the Arctic Polar Vortex (CHAOS_A)

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.

PSC Atmospheric processes BrO UV radiation UV-Vis spectrometer NO2 Arctic Temperature profiles. Atmosphere OClO
55. stratospheric balloon soundings

In situ measurements in the stratosphere shall be carried out by means of different balloon soundings. The main goal is the investigation of aerosols in the tropopause-region and in the stratosphere during wintertime. Because generation of aerosols strongly depends on water vapour content, also water vapour will be measured.

Atmospheric processes Pollution sources Arctic balloon soundings Atmosphere
56. Enhanced deposition of atmospheric mercury during Arctic sunrice _ International campain/intercompariosn

The general objective of the project is to increase the understanding of the Mercury Depletion Events occuring at Arctic sunrise and to quantify the input of mercury to polar ecosystems during this events.

Atmospheric processes Long-range transport
57. Dayside Aurora

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

Atmospheric processes Atmosphere Aurora. Space Physics.
58. Mercury Measurements in Ny-Ålesund

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.

Atmospheric processes Atmosphere
59. ASTAR 2000

ASTAR, Arctic Study of Tropospheric Aerosol and Radiation is a a joint German (AWI Potsdam) - Japanese (NIPR Tokyo) campaign with participation from NASA LaRC Hampton, VA (USA). In addition to AWI, NIPR, and NASA LaRC the following institutions contributed to the project: Hokkaido University (Japan), Nagoya University (Japan), Norwegian Polar Institute Tromsoe/ Longyearbyen (Norway), NILU Kjeller (Norway), MISU Stockholm (Sweden), NOAA-CMDL Boulder, CO (USA) and Max Planck Institute for Aeronomy Katlenburg-Lindau (Germany). The campaign is based on simultaneous airborne measurements from the German research aircraft POLAR 4 and ground-based measurements in Ny-Ålesund. The main goals of the project are - to measure aerosol parameters of climate relevance, like extinction coefficient, absoprtion coefficients and phase function. - to create an Arctic Aerosol Data Set for climate impact investigation by using the regional climate model HIRHAM. - to carry out comparison measurements with the SAGE II (Stratospheric Aerosol and Gas Experiment) and the ground based Raman-Lidar.

Radiation Atmospheric processes Phase function Absoprtion coefficients HIRAM Climate variability Climate Climate change Aerosol Arctic Raman-Lidar Atmosphere Extinction coefficient SAGE II
60. SOLVE: SAGE III Ozone Loss and Validation Experiment

In preparation to the launch of the SAGE III experiment in March 2001, NASA and the European Union performed the SOLVE / THESEO-2000 campaign, which had three components: (i) an aircraft campaign using the NASA DC-8 and ER-2 airplanes out of Kiruna/Sweden, (ii) launches of large stratospheric research balloons from Kiruna, (iii) validation excercises for the commissioning phase of SAGE III. The German Arctic research station Koldewey in Ny-Ålesund/Spitsbergen contributes to (i), (ii), and (iii) by performing measurements of stratospheric components like ozone, trace gases, aerosols (PSCs), temperature and winds. The measurement results were transmitted quasi online to the flight planning center in Kiruna, in order to allow a better directing of the air plane flights. In addition the Koldewey-Station has been designated a validation anchor site for the SAGE III validation. The activities are organized within a NASA accepted proposal of ground-based validation support by the NDSC Primary Station at Ny-Ålesund, Spitsbergen and by a SAGE III validation working group for Ny-Ålesund. The main observation periods are from December 1999 to March 2000.

Atmospheric processes Ozone UV radiation trace gases Climate variability Climate SAGE III Climate change aerosol THESEO-2000 PSCs Atmosphere satellite validation