(Table 1) Air-earth current density investigated during Atlantic Expedition 1973 of METEOR

One main point of our atmospheric-electric measurements over the Atlantic Ocean 1973 was the investigation of the air-earth current density above the sea. In addition to direct measurements at the water surface with a floating net, we calculated the air-earth current density from the electric field and the air conductivity measured simultaneously on board of the ship and during particular ascents in the free atmosphere. During all five ascents the air-earth current density did not change with altitude. For pure maritime air-conditions, the mean air-earth current density was found to be 2.9 pA/m**2. The mean hourly air-earth current density over the Atlantic shows nearly the same 24-hour pattern as measured by Cobb (1977) at the South Pole at the same time. When dust-loaden air masses of African origin reached the ship as well as under continental influence the mean air-earth current density was reduced to 2.1 pA/m**2. The global 24-hour pattern was modified by this continental influences. Finally, it is shown that the values of the air conductivity measured on board R. V. "Meteor" during our earlier expeditions have been influenced by the exhaust of the ship and must therefore be corrected. With this correction, our new mean values of the air-earth current density over the Atlantic are 2.6 pA/m**2 in 1965 and 2.0 pA/m**2 in 1969. From all measurements, the global air-earth current is estimated to be about 1250 A.

Mean air temperatures of Greenland

Melt rate and surface temperature on the Greenland ice sheet are parameterized in terms of snow accumulation, mean annual air temperatur and mean July air temperature. Melt rates are calculated using positive degree-days, and firn warming (i.e. the positive deviation of the temperature at 10-15 m depth from the mean annual air temperature) is estimated from the calculated amount of refrozen melt water in the firn. A comparison between observed and calculated melt rates shows that the parameterization provides a reasonable estimate of the present ablation rates in West Greenland between 61°N and 76°N. The average equilibrium line elevation is estimated to be about 1150 m and 1000 m for West and East Greenland respectively, which is several hundred meter lower than previous estimates. However, the total annual ablation from the ice sheet is found to be about 280 km**3 of water per year which agrees well with most other estimates. The melt-rate model predicts significant melting and consequently significant firn warming even at the highest elevations of the South Greenland ice sheet, whereas a large region of central Greenland north of 70° N experiences little or no summer melting. This agrees with the distribution of the dry snow facics as given by BENSON (1962).

Air concentration of polybrominated diphenyl ethers around the Great Lakes and the Arctic

Atmospheric PBDEs were measured on a monthly basis in 2002-2004 at Point Petre, a rural site in the Great Lakes. Average air concentrations were 7.0 ± 13 pg/m**3 for the sum of 14BDE (excluding BDE-209), and 1.8 ± 1.5 pg/m**3 for BDE-209. Concentrations of 3 dominant congeners (i.e., BDE-47, 99, and 209) were comparable to previous measurements at remote/rural sites around the Great Lakes, but much lower than those at urban areas. Weak temperature dependence and strong linear correlations between relatively volatile congeners suggest importance of advective inputs of gaseous species. The significant correlation between BDE-209 and 183 implies their transport inputs associated with particles. Particle-bound percentages were found greater for highly brominated congeners than less brominated ones. These percentages increase with decreasing ambient temperatures. The observed gas/particle partitioning is consistent with laboratory measurements and fits well to the Junge-Pankow model. Using air mass back-trajectories, atmospheric transport to Point Petre was estimated as 76% for BDE-47, 67% for BDE-99, and 70% for BDE-209 from west-northwest and southwest directions. During the same time period, similar congener profiles and concentration levels were found at Alert in the Canadian High Arctic. Different inter-annual variations between Point Petre and Alert indicate that emissions from other regions than North America could also contribute PBDEs in the Arctic. In contrast to weak temperature effect at Point Petre, significant temperature dependence in the summertime implies volatilization emissions of PBDEs at Alert. Meanwhile, episodic observations in the wintertime were likely associated with enhanced inputs through long-range transport during the Arctic Haze period.

Aerosol concentrations measured along the track of METEOR cruise M16

During the third part of the Atlantic Expedition 1969 from 10° S to 60° N along 30° W, measurements of the complete size distribution of atmospheric aeosols over the whole size range from about 10**-7 to 10**-2 cm radius were made. This was possibe by the simultaneous operation of different methods which are critically discussed. The results obtained are the first of its kind and are of general interest despite some methodical shortcomings. North of the equator the ship passed through air masses of west African origin and the influence of Sahara dust on the Marine aerosols could be documented in a unique way. The Sahara dust component was restricted to the size range of 10**-5 to 10**-3 radius. Throughout the voyage particles up to 10**-2 radius were always found to be present, similar to findings over continents. Of special interest is the observation that the size distribution extends to very small particles, suggesting continuous aerosol production over the ocean.

Phytoplankton production, photosynthetic (P vs E) parameters, and particulate organic carbon and nitrogen within distinct water masses of eastern Australian coastal and shelf waters between 29 °S and 36 °S during spring 2010

The present dataset is part of an interdisciplinary project carried out on board the RV Southern Surveyor off New South Wales (Australia) from the 15th to the 31st October 2010. The main objective of the research voyage was to evaluate how the East Australian Current (EAC) affects the optical, chemical, physical, and biological water properties of the continental shelf and slope off the NSW coast.