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.

Environmental context of selected samples from the Tara Oceans Expedition (2009-2013)

The present data set provides contextual environmental data for samples from the Tara Oceans Expedition (2009-2013) that were selected for publication in a special issue of the SCIENCE journal (see related references below). The data set provides calculated averages of mesaurements made at the sampling location and depth, calculated averages from climatologies (AMODIS, VGPM) and satellite products.

Mass balance and acceleration of the Greenland ice sheet

Within the last decade, the Greenland ice sheet (GrIS) and its surroundings have experienced record high surface temperatures (Mote, 2007, doi:10.1029/2007GL031976; Box et al., 2010), ice sheet melt extent (Fettweis et al., 2011, doi:10.5194/tc-5-359-2011) and record-low summer sea-ice extent (Nghiem et al., 2007, doi:10.1029/2007GL031138). Using three independent data sets, we derive, for the first time, consistent ice-mass trends and temporal variations within seven major drainage basins from gravity fields from the Gravity Recovery and Climate Experiment (GRACE; Tapley et al., 2004, doi:10.1029/2004GL019920), surface-ice velocities from Inteferometric Synthetic Aperture Radar (InSAR; Rignot and Kanagaratnam, 2006, doi:10.1126/science.1121381) together with output of the regional atmospheric climate modelling (RACMO2/ GR; Ettema et al., 2009, doi:10.1029/2009GL038110), and surface-elevation changes from the Ice, cloud and land elevation satellite (ICESat; Sorensen et al., 2011, doi:10.5194/tc-5-173-2011). We show that changing ice discharge (D), surface melting and subsequent run-off (M/R) and precipitation (P) all contribute, in a complex and regionally variable interplay, to the increasingly negative mass balance of the GrIS observed within the last decade. Interannual variability in P along the northwest and west coasts of the GrIS largely explains the apparent regional mass loss increase during 2002-2010, and obscures increasing M/R and D since the 1990s. In winter 2002/2003 and 2008/2009, accumulation anomalies in the east and southeast temporarily outweighed the losses by M/R and D that prevailed during 2003-2008, and after summer 2010. Overall, for all basins of the GrIS, the decadal variability of anomalies in P, M/R and D between 1958 and 2010 (w.r.t. 1961-1990) was significantly exceeded by the regional trends observed during the GRACE period (2002-2011).