Projects/Activities

FT-IR spectrometers are capable to quantifiy the total column amounts of many important trace gases in the troposphere and stratosphere. At present the following species are retrieved from the Kiruna data: O3 (ozone), ClONO2, HNO3, HCl, CFC-11, CFC-12, CFC-22, NO2, N2O, NO, HF, C2H2, C2H4, C2H6, CH4, CO, COF2, H2O, HCN, HO2NO2, NH3, N2, and OCS Selected research topics and activities: chemical ozone depletion by observation of key species (O3, ClONO2, HNO3, HCl, ..) details of the ozone formation process by isotopic studies in ozone profile retrieval to detect dynamical changes transport studies of chemical tracers and tropospheric pollutants satellite validation

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

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

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.

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.

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.

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.

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

These investigations confirm the fact that in the stratosphere the ozone is considerably influenced by dynamical processes and it is a good indicator of them. In this context the main objectives of the proposed study are: 1) to investigate the possible relationship between stratospheric ozone perturbations and the temperature enhancement in the upper mesosphere, observed by Shepherd et al. (2001); 2) to examine whether changes in ozone, concomitant with the phenomenon, take place and how and when they would be manifested; and 3) to investigate the stratospheric ozone behaviour during the equinox atmospheric transition in the North Hemisphere, for better understanding of the middle atmosphere dynamics.

A high precise GPS-receiver with high time resolution is operated together with the Norwegian Mapping Authority in Ny Ålesund since 1999. Datasets are transmitted continuously and automatically via Internet to the GFZ in Potsdam where they are evaluated for two purposes. Firstly to determine station coordinates, ephemerides for all GPS-satellites and high temporal resolved vertical integrated water vapor for the International GPS Service (IGS). Secondly they are used as reference for the CHAMP-satellite to determine its exact orbit and to calculate water vapor profiles from on board GPS-receiver-data.

CHAMP (CHAllenging Minisatellite Payload) is a German small satellite mission for geoscientific and atmospheric research and applications, managed by GFZ. With its highly precise, multifunctional and complementary payload elements (magnetometer, accelerometer, star sensor, GPS receiver, laser retro reflector, ion drift meter) and its orbit characteristics (near polar,low altitude, long duration) CHAMP will generate for the first time simultaneously highly precise gravity and magnetic field measurements over a 5 years period. This will allow to detect besides the spatial variations of both fields also their variability with time. The CHAMP mission will open a new era in geopotential research and will become a significant contributor to the Decade of Geopotentials.

Project Description: - Landform mapping of the periglacial and glacial structures using remote sensing / aerial photography and field observation - Genetic studies of ground ice using geochemical and stable isotope techniques - Studies of microbial life in extreme periglacial environment

Study of the energy exchange between atmosphere, sea ice and ocean during freezing and melting conditions; within that, measurements of solar radiation (visible and UV) and optical properties, snow and sea ice characteristics, vertical heat and salt fluxes, oceanographic parameters.

Changes in surface reflection at the arctic tundra at Ny-Ålesund, Svalbard (79 N) were monitored during the melting season 2002 using a low cost multispectral digital camera with spectral channels similar to channels 2, 3, and 4 of the Landsat Thematic Mapper satellite sensor. The camera was placed 474 m above sea level at the Zeppelin Mountain Research Station and was programmed to take an image automatically every day at solar noon. To achieve areal consistency in the images (which is necessary for mapping purposes) the images were geometrically rectified into multispectral digital orthophotos. In contrast to satellite images with high spatial resolution the orthophotos provide data with high spatial and high temporal resolution at low cost. The study area covers approximately 2 km2 and when free of snow, it mainly consists of typical high arctic tundra with patchy vegetation and bare soil in between. The spectral information in the images was used to divide the rectified images into maps representing different surface classes (including three subclasses of snow). By combining classified image data and ground measurements of surface reflectance, a model to produce daily maps of surface albedo was developed. The model takes into account that snow-albedo decreases as the snow pack ages; and that the albedo decreases very rapidly when the snow pack is shallow enough (20-30 cm) to let surface reflectance get influenced by the underlying ground. Maps representing days with no image data (due to bad weather conditions) were derived using interpolation between pixels with equal geographical coordinates. The time series of modeled albedo-maps shows that the time it takes for the albedo to get from 80% to bare ground levels varies from less than 10 days in areas near the coast or in the Ny-Ålesund settlement till more than 70 days in areas with large snow accumulations. For the entire study area the mean length of the 2002 melting period was 28.3 days with a standard deviation of 15.1 days. Finally, the duration of the snowmelt season at a location where it is measured routinely, was calculated to 23 days, which is very close to what is the average for the last two decades.

3-D GPR (ground penetrating radar) profiling of permafrost deposits and examination of their geocryologic and sediment properties for verification of GPR profiles. The scientific project has the following aims: To improve the understanding of how GPR (ground penetrating radar) reflections are generated in frozen ground; to reveal the main factors (geophysical and sedimentary) controlling electromagnetic reflection characteristics and their spatial continuity as examplarily studied along a continuous permafrost section, i.e. to distinguish between physical (dielectricity, conductivity and density) and sedimentary (ice/water content, grain size distribution, content of organic matter, texture) properties and estimate their proportionate quantity on the origin of the wave reflections.

The active layer, the annually freezing and thawing upper ground in permafrost areas, is of pivotal importance. The moisture and heat transfer characteristics of this layer also determine the boundary layer interactions of the underlying permafrost and the atmosphere and are therefore important parameters input for geothermal or climate modeling. Finally, changes in the characteristics of the permafrost and permafrost related processes may be used as indicators of global ecological change provided the system permafrost-active layer-atmosphere is understood sufficiently well. The dynamics of permafrost soils is measured with high accuracy and high temporal resolution at our two sites close to Ny-Ålesund, Svalbard. Using these continuous data we quantify energy balance components and deduce heat transfer processes such as conductive heat flux, generation of heat from phase transitions, and migration of water vapor.