Otto Schrems

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Tower-based measurements of hydrogen peroxide (H2O2) and formaldehyde (HCHO) exchange were performed above the snowpack of the Greenland ice sheet. H2O2 and HCHO fluxes were measured continuously between 16 June and 7 July 2000, at the Summit Environmental Observatory. The fluxes were determined using coil scrubber-aqueous phase fluorometry systems together(More)
Hexachlorocyclohexanes (HCHs) were determined simultaneously in air and seawater during two cruises across the Atlantic Ocean between the Arctic Ocean (Ny-Alesund/ Svalbard, 79 degrees N; 12 degrees E) and the Antarctic Continent (Neumayer Station/ Ekstroem Ice Shelf, 70 degrees S; 8.2 degrees W) in 1999/ 2000. The concentrations of alpha-HCH and gamma-HCH(More)
A unique data set of ship-borne lidar measurements of Saharan dust layers above the Atlantic ocean has been collected aboard the research vessel Polarstern with a mobile Aerosol Raman Lidar (MARL) during the LIMPIDOcampaign in June 2000. Extended Saharan dust layers have been observed in the region between 8.5 N and 34 N in an altitude range between 2 and 6(More)
[1] In the framework of the European Project STAR the Mobile Aerosol Raman Lidar (MARL) of the Alfred Wegener Institute (AWI) was operated in Paramaribo, Suriname (5.8 N, 55.2 W), and carried out extensive observations of tropical cirrus clouds during the local dry season from 28 September 2004 to 16 November 2004. The coverage with ice clouds was very high(More)
Carbonyl sulfide (COS) is considered to be a major source of the stratospheric sulfate aerosol during periods of volcanic quiescence. We measured COS at the tropical tropopause and find mixing ratios to be 20 to 50% larger than are assumed in models. The enhanced COS levels are correlated with high concentrations of biomass-burning pollutants like carbon(More)
[1] We present the first ground-based solar absorption Fourier Transform Infrared (FTIR) spectrometric measurements in the inner tropics over several years. The FTIR observations agree well with satellite data from the MOPITT instrument. MATCH-MPIC model simulations reproduce the mean vertical structure of the FTIR observations. The model is generally not(More)
Ship-borne measurements of spectral as well as biologically effective UV irradiance have been performed on the German research vessel Polarstern during the Atlantic transect from Bremerhaven, Germany (53.5 degrees N, 8.5 degrees E), to Cape Town, South Africa (33.6 degrees S, 18.3 degrees E), from 13 October to 17 November 2005. Such measurements are(More)
Dual wavelength Raman lidar observations of tropical high-altitude cirrus clouds were performed during the ALBATROSS 1996 campaign aboard the German research vessel “POLARSTERN” on the Atlantic ocean in October– November 1996. On the basis of 475 observations bet wecn 23.5”N and 23.5° S we find in 72% of the altitude profiles indications of the presence of(More)
Laboratory-made snow doped with either hydrogen peroxide (H2O2) or formaldehyde (HCHO) was exposed to radiation in the UV and visible range resulting in a decomposition of both compounds. These experiments demonstrate that besides the photolysis of nitrate further photochemical reactions of atmospheric relevant compounds can take place in snow. Under(More)
Column-averaged volume mixing ratios of CO2 have been obtained by ground based high-resolution solar absorption spectrometry at Ny-Alesund (Spitsbergen, 79°N) in 20022003 and during two ship cruises (54°N34°S) on the Atlantic in 2003. Precisions are better than 0.4% at Ny-Alesund and better than 0.6% for the cruises. The observed 11 ppmv (part per million(More)