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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 aim of the project is to study the properties (radiative effects, composition) of aerosols using FTIR emission spectroscopy. To determine seasonal changes in aerosol properties the measurements will be carried out year round on a weekly schedule.
The main objective is to establish a scientific basis for the detection of the earliest signs of ozone recovery due to Montreal protocol and its amendments. To achieve this we will select the best long-term ozone and meteorological data sets available (by ECMWF and NCEP). Ozone data will be studied by using advanced multiple regression methods developed in this project. Meteorological data would allow to determine the dynamical changes and trends and assess their role in re-distribution of stratospheric ozone in recent decades and in order to force the Chemical Transport Models to assess the relative roles of chemistry and transport in ozone changes. Finally, the synthesis of the key objectives will improve the attribution of observed ozone changes to anthropogenic influences and to the variations in a natural atmosphere.
A dedicated study into the formation of new particles, PARFORCE (New particle formation and fate in the coastal environment), was conducted over a period from 1998-1999 at the Mace Head Atmospheric Research Station on the western coast of Ireland. Continuous measurements of new particle formation were taken over the two-year period while two intensive field campaigns were also conducted, one in September 1998, and the other in June 1999. New particle events were observed on »90% of days and occurred throughout the year and in all air mass types. These events lasted for, typically, a few hours, with some events lasting more than 8 hours, and occurred during daylight hours coinciding with the occurrence of low tide and exposed shorelines. During these events, peak aerosol concentrations often exceeded 10 6 cm -3 under clean air conditions while measured formation rates of detectable particle sizes (i.e. d > 3nm) were of the order of 10 4 -10 5 cm -3 s -1 . Nucleation rates of new particles were estimated to be, at least, of the order of 10 5 -10 6 cm -3 s -1 and occurred for sulphuric acid concentrations above 2 x 10 6 molecules cm -3 ; however, no correlation existed between peak sulphuric acid concentrations, low tide occurrence or nucleation events. Ternary nucleation theory of the H2SO4-H2O-NH3 system predicts that nucleation rates far in excess of 10 6 cm -3 s -1 can readily occur for the given sulphuric acid concentrations; however, aerosol growth modelling studies predict that there is insufficient sulphuric acid to grow new particles (of »1 nm in size) into detectable sizes of 3 nm. Hygroscopic growth factor analysis of recently-formed 8 nm particles illustrate that these particles must comprise some species significantly less soluble than sulphate aerosol. The nucleation-mode hygroscopic data, combined with the lack of detectable VOC emissions from coastal biota, the strong emission of biogenic halocarbon species, and the finger-printing of iodine in recently-formed (7 nm) particles suggest that the most likely species resulting in the growth of new particles to detectable sizes is an iodine oxide as suggested by previous laboratory experiments. It remains an open question whether nucleation is driven by self nucleation of iodine species, a halocarbon derivative, or whether first, stable clusters are formed through ternary nucleation of sulphuric acid, ammonia and water vapour, followed by condensation growth into detectable sizes by condensation of iodine species. Airborne measurements confirm that nucleation occurs all along the coastline and that the coastal biogenic aerosol plume can extend many 100s of km away from the source. During the evolution of the coastal plume, particle growth is observed up to radiatively-active sizes of 100 nm. Modelling studies of the yield of cloud-condensation nuclei suggest that the cloud condensation nuclei population can increase by »100%. Given that the production of new particles from coastal biogenic sources occurs at least all along the western coast of Europe, and possibly many other coastlines, it is suggested that coastal aerosols contribute significantly to the natural background aerosol population.
The International Panel on Climate Change (IPCC) has very recently revised the prediction of global average temperature increase during the next century from 1.0-3.5 to 1.4-5.8 K. The increase in the upper limit of the prediction is largely due to the role of aerosols in the climate of the Earth: it is believed that reduction of pollution will result in reduced direct and indirect (via clouds) scattering of sunlight back to the space. However, as can be seen from the large uncertainty of the estimated temperature increase, not enough is known about the role of natural and anthropogenic aerosols in climate processes. This is also reflected in the Key Action 2, under the RTD priority 2.1.1, calling for ”… quantification and prediction of … concentration of … aerosols, in particular the fine fraction of particles and their precursors”. The concentration of aerosols is controlled by their sources and sinks, and thus the prediction of particle concentration requires the quantification of aerosol source terms. The main objective of QUEST is to quantify the number of new secondary aerosol particles formed through homogeneous nucleation in the European boundary layer, and the relative contributions of natural and anthropogenic sources. The role of homogeneous nucleation in the formation of new atmospheric particles was realized in the 1990s, and considerable effort has been devoted to studies of aerosol formation in various parts of the Globe. The longest continuous data series of nucleation events has been obtained at a forest field station in Finland, where aerosol size distributions between 3 and 150 nm in diameter have been recorded in 10 minute intervals since the beginning of 1996 . Nucleation events occur in this rather clean Boreal area roughly 50-60 times per year, the highest event frequency taking place in the spring months (March-May). The concentration of new particles per cc of air formed during one event varies between roughly 100-10 000. Taking the average number to be one thousand, and assuming that the nucleation takes place in a well mixed boundary layer having a height of 1000 m, it can be estimated that the aerosol source term in the Boreal forest area is on the order of 51013 m-2 per year. This is on the same order as the global aerosol yield estimated from primary emissions . The number given here is very crude as we can at present only guess the vertical extent of the nucleation zone; however, it clearly shows that homogeneous nucleation events influence atmospheric particle concentrations at least at regional scales, and possibly also globally. Many features of the Boreal nucleation events have been revealed thus far. Necessary (but not sufficient) conditions include sunny weather, vertical mixing of air in the morning (prior to the detection of the event) , and a treshold value of a quantity that depends on radiation intensity (vapor source) and pre-existing aerosol size distribution (vapor sink) . The springtime events always seem to take place in Polar or Arctic air masses , but so far it is unclear whether the meteorology is similar during other seasons. Aerosol flux measurements  indicate that the particles are formed aloft, but the vertical extent of the nucleation layer is unknown. However, there is clear evidence from simultaneous measurements at various locations, that the horizontal extent of the areas in which the nucleation takes place can be hundreds and in some cases even thousands of kilometers . No direct correlation of nucleation events with SO2 concentrations has been found; however the product of SO2 concentration, ammonia concentration, and calculated OH concentration correlates with the events (personal communication). These results hint that the recently suggested ternary sulfuric acid-ammonia-water nucleation mechanism of small clusters, followed by the growth of the clusters due to condensation of other (possibly organic) vapors , may be operational in the Boreal forest area. Furthermore, there is experimental evidence that nucleation event particles in the 4-5 nm range are soluble in butanol (working fluid of condensation particle counters), which indicates organic composition. However, the confirmation of the ternary nucleation hypothesis requires simultaneous measurements of sulfuric acid vapor and ammonia, and further studies of the composition of the nucleated particles. Furthermore, to facilitate large-scale modelling studies, the vertical extent of the nucleation events, as well as the meteorological conditions during non-springtime events have to be investigated. Measurements of nucleation events at a more Central European location indicate that SO2 levels increase during the majority of nucleation events . It can be hypothesized that a part of observed nucleation events (minority in Central Europe, majority in the Boreal area) are ”natural” and a part are affected (or even caused) by pollution (majority in Central Europe, minority in the Boreal area). The confirmation of this hypothesis and implementation of the pollution type nucleation mechanism into a large-scale model requires carefully designed measurements from a location which is preferably Southern European as there is very little available nucleation data from this area. One of the few observations of new particles in Southern Europe  is from the Italian site where we plan to study the frequency, meteorology, vertical extent, and chemical precursors of nucleation events. Another type of nucleation events has been observed all along the western coast of Europe and have been studied more particularly at the west coast of Ireland . These events, which have a duration of the order of 4 hours and up to 8 hours, occur almost daily around low tide and under conditions of solar radiation, indicating photochemical source. Incredibly, the peak new particle concentrations often exceed 106 cm-3, making this the strongest natural source region of atmospheric particles. The exact chemical mechanisms leading to the production of coastal particles still remains an open question. As in other environments, there appears to be sufficient sulphuric acid vapour to participate in ternary nucleation with ammonia and water, however, there is insufficient sulphuric acid to grow these particles to detectable sizes . The most probable chemical species involved in the production or growth of these particles is Iodine, or an Iodine Oxide, produced photochemically from biogenic halocarbon emissions . The production of particles from the photolysis of CH2I2 in the presence of ozone has been confirmed by recent smog chamber experiments . While the concentration of new particles in this environment is extraordinarily high, its impact on background particle and CCN contribution remains unclear and needs to be quantified. A limited single study  has shown that the coastal aerosol plume is detectable up to several hunderds of km downwind and that the new coastal particles readily grow into CCN sizes (larger than 100 nm). An intensive campaign at the coast of Ireland will quantify the flux of both biogenic halocarbon precursor gases and the yield of new, and radiatively-active particles in the European coastal boundary layer. The objective of QUEST is to determine the source strength of new particle formation in the three above mentioned cases. The specific objectives are: 1) To fill in gaps that exist in the understanding of chemical and physical pathways leading to homogeneous nucleation of new aerosol particles; 2) To understand the meteorological conditions required for the events to take place and to be able to predict the horizontal and vertical extent of the events; 3) To implement parametrized representations of the nucleation mechanisms, based on the information from 1) and 2), to an European scale model in order to determine the source strength of homogeneous nucleation of aerosol particles in the European boundary layer.
The German Aerospace Center (DLR) Bi-spectral Infrared Detection (BIRD) small satellite is a technology demonstrator of new infrared push-broom sensors dedicated to recognition and quantitative characterisation of thermal processes on the Earth surface. BIRD was successfully piggy-back launched on October 22, 2001 with an Indian Polar Satellite Launch Vehicle (PSLV-C3) into a circular sun-synchronous orbit with an altitude of 572 km and a North - South local equator crossing time at 10:30 h. Besides cameras working in the visible and near infrared spectral range there are two cameras working in the middle infrared (MIR, 3.4 – 4.2 µm) and in the thermal spectral range (TIR, 8.5 – 9.3 µm) respectively. The objective is to validate these two cameras in cooperation with the Koldewey-Station in Ny-Ålesund. Therefore meteorological and aerological data as well as radiation measuring data will be used.
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.
Aim of the project is to develop a cost-effective long-term European observation system for halocarbons and to predict and assess impacts of the halocarbons on the climate and on the ozone layer. Beside the routine observations within the NDSC it is planned to perform with FTIR (Fourier Transform Infrared Spectroscopy) absorption measurements of CFCs (e.g. SF6, CCl2F2, CHF2Cl) and related species on much more observation days.
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.
The subject is to determine the horizontal distribution of aerosol and trace gases by airborne measurements with the Gulfstream III (transarctic flight), ground based measurements in Ny Ålesund (Koldewey Station, Rabben) and satellite measurements with SAGE II / SAGE III. Objective is to get vertical and horizontal aerosol profiles, to research the trace gase variations in the Arctic and to compare remote sensing und in situ measurements.
In situ measurements of the tropospheric and tropopause and if possible lower stratospheric water vapour content will be carried out with different balloon sondes. Start of up to three balloons with Snow White Sensor-Package prepared by a team from the University of Nagoya and University of Kyoto. Possibly water vapour sondes from NOAA (S. Oltmans) will be started within the scope of an EU-project. This may happen earliest in autumn.
By launching several hundred ozonesondes and by ozone lidar measurements at many Arctic and sub-Arctic stations, one of them Ny-Ålesund, the stratospheric chemical ozone loss will be determined. The launches of all stations will be coordinated by analysis of trajectory calculations based on analysis and forecast wind fields. The aim is to get as many ozone sounding pairs as possible, each of them linked by trajectories in space and time. A statistical description of the ozone differencies given by the first and the second measurement of individual sonde pairs will yield the chemical ozone loss with spatial and time resolution. Four similar campaigns took place in the Arctic and in the mid-latitudes covering the time period of Januar to March in each of the last four winters. In the first three winters high ozone depletion rates (20 - 50 ppbv per day) were determined in some height levels within the polar vortex. In the height level of the ozone maximum an integrated ozone loss (during the winter) in the order of 60 % have been found. These are record ozone losses for the Arctic polar region. In the last winter the ozone depletion rates had been much lower due to moderate temperatures in the stratosphere.
The FTIR (Fourier Transform Infrared Spectroscopy) has been established as a powerful tool for measurements of atmospheric trace gases. Using the sun or moon as light source, between 20-30 trace gases of the tropo- and stratosphere can be detected by their absorption features. The analysis of the spectra allow to retrieve the total zenith columns of the trace gases. The aim of the SAMMOA project is to study the stratospheric ozon depletion during the summer time period. While the processes during winter/spring are investigated in detail the summertime ozone loss has not been studied so far. Therefore FTIR solar absorption measurements of ozone and related species are to be done on much more observation days beside the routine observations within the NDSC
Quasi-continuous observation of several atmospheric species are performed by measuring the absorption of visible and near ultraviolet sunlight scattered from the sky or in direct moonlight. Column abundance of molecules such as ozone, NO2, OClO, NO3, BrO, HCHO and IO are derived by means of a Differential Optical Absorption (DOAS) algorithm and a radiative transfer model. These activities are part of calibration and validation studies of different satellite experiments (GOME, SAGE III, SCIAMACHY). Since 1999 the instrument is part of the Network of the Detection of Stratospheric Change (NDSC). The instrument has been installed in 1995 as the second UV/vis instrument from the Institute of Environmental Physics. One similar setup in Bremen is continuously running with the exception of short maintenance breaks since 1993.
The FTIR (Fourier Transform Infrared Spectroscopy) has been established as a powerful tool for measurements of atmospheric trace gases. Using the sun or moon as light source, between 20-30 trace gases of the tropo- and stratosphere can be detected by their absorption features. The analysis of the spectra allows to retrieve the total zenith columns of the trace gases. For a few trace gases the pressure broadening of the lines allows to get additionally some information on the vertical concentration profiles. Some important trace gases cannot be detected in the IR but in the UV/VIS. This makes it useful to record the whole spectral region from the IR from about 700/cm (14 µm) to the UV at 33000/cm (300 nm).
Microwave radiometers are part of the standard instrumentation at primary NDSC stations and are due to their long-term stability and self calibrating technique especially useful for monitoring purposes. Altitude profiles are retrieved from the shape of the pressure broadened thermally induced emission line of the observed species. The instruments for the observation of stratospheric ozone, chlorine monoxide and water vapour at the Koldewey Station in Ny-Ålesund were developed at the University of Bremen and upgrades and improvements are regularly carried out. The instruments have been automated during recent years and ozone and water vapour observation on Spitsbergen are carried out all year round. Chlorine monoxide is only observed in late winter and early spring, when enhanced concentrations in the lower stratosphere are to be expected. Routine operation and maintenance are done by the station engineer. Data analysis is carried out at the University of Bremen.
In recent years, much attention has been directed towards understandig the effects of aerosols on a variety of processes in the earth atmosphere. Aerosols play an integral role in limiting visibility, they serve as nuclei for the formation of fog and cloud droplets, they affect the earth radiative budget, and thus climate, both directly and indirectly, and they inhibit the propagation of electromagnetic radiation. The Arctic aerosols, especially Arctic Haze and tropospheric ice crystals possible have important climatic and ecological and global change implications. Since 1991 Sun photometer observations of the polar atmopheric aerosol have been performed at the Koldewey Station in Ny-Aalesund, Spitzbergen. In order to complete the coverage and quality of measurements during the polar night a high sensitive Star photometer is installed since January 1996. Both measurements, the daylight Sun photometer measurements and night Star photometer measurements will be continued.
The Baseline Surface Radiation Network (BSRN) is a cooperative network of surface radiation budget. Measurement stations operated by various national agencies and universities under the guiding principle set out by the World Climate Research Programme (WCRP). Presently about 15 stations have been established, one of them is Ny-Ålesund. The concept for a Baseline Surface Radiation Network has developed from the needs of both the climate change and satellite validation communities. The aims of the programme are the monitoring of long-term trends in radiation fluxes at the surface and the providing validation data for satellite determinations of the surface radiation budget. The BSRN station Ny-Aalesund was installed in summer 1992 and is regularly operating since August 1992.
Permanent monitoring of basic climate data for the purpose of better understanding the Arctic climate processes and detecting trends.