Four-dimensional distribution of the 2010 Eyjafjallajökull volcanic cloud over Europe observed by EARLINET

© Author(s) 2013. This work is distributed under the Creative Commons Attribution 3.0 License.The eruption of the Icelandic volcano Eyjafjallaj ökull in April-May 2010 represents a "natural experiment" to study the impact of volcanic emissions on a continental scale. For the first time, quantitative data about the presence, altitude, and layering of the volcanic cloud, in conjunction with optical information, are available for most parts of Europe derived from the observations by the European Aerosol Research Lidar NETwork (EARLINET). Based on multi-wavelength Raman lidar systems, EARLINET is the only instrument worldwide that is able to provide dense time series of high-quality optical data to be used for aerosol typing and for the retrieval of particle microphysical properties as a function of altitude. In this work we show the four-dimensional (4-D) distribution of the Eyjafjallajökull volcanic cloud in the troposphere over Europe as observed by EARLINET during the entire volcanic event (15 April-26 May 2010). All optical properties directly measured (backscatter, extinction, and particle linear depolarization ratio) are stored in the EARLINET database available at www.earlinet.org. A specific relational database providing the volcanic mask over Europe, realized ad hoc for this specific event, has been developed and is available on request at www.earlinet.org. During the first days after the eruption, volcanic particles were detected over Central Europe within a wide range of altitudes, from the upper troposphere down to the local planetary boundary layer (PBL). After 19 April 2010, volcanic particles were detected over southern and south-eastern Europe. During the first half of May (5-15 May), material emitted by the Eyjafjallajökull volcano was detected over Spain and Portugal and then over the Mediterranean and the Balkans. The last observations of the event were recorded until 25 May in Central Europe and in the Eastern Mediterranean area. The 4-D distribution of volcanic aerosol layering and optical properties on European scale reported here provides an unprecedented data set for evaluating satellite data and aerosol dispersion models for this kind of volcanic events.Peer reviewe

Die Analyse des Verhaltens von Leitern im Problembearbeitungsprozess und ihre methodischen Moeglichkeiten eine Problemstudie

SIGLEUni.Jena, Inst.f.Psychologie - V IIIa 208 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

The 16 April 2010 major volcanic ash plume over central Europe : EARLINET lidar and AERONET photometer observations at Leipzig and Munich, Germany

The optically thickest volcanic ash plume ever measured over Germany was monitored with multiwavelength Raman lidars and Sun photometer at Leipzig and Munich. When this ash layer, originating from the Eyjafjoll eruptions in southern Iceland, crossed Leipzig between 2.5 and 6 km height on 16 April 2010, the total 500 nm aerosol optical depth reached 1.0, and the ash-related optical depth was about 0.7. Volume light-extinction coefficients (40-75-minute mean values) measured over Leipzig and Munich at 355 and 532 nm reached values of 400-600 Mm(-1) and ash mass concentrations were on the order of 1000 +/- 350 mg/m(3) in the center of the main ash layer. Extinction-to-backscatter ratios ranged from 55 +/- 5 sr (Munich) to 60 +/- 5 sr (Leipzig) in the main ash layer, and the particle linear depolarization ratio was close to 0.35 at both wavelengths. Rather low photometer-derived Angstrom exponents (500-1640 nm wavelength range) indicated the presence of a significant amount of large ash particles with diameters >20 mu m. Citation: Ansmann, A., et al. (2010), The 16 April 2010 major volcanic ash plume over central Europe: EARLINET lidar and AERONET photometer observations at Leipzig and Munich, Germany, Geophys. Res. Lett., 37, L13810, doi: 10.1029/2010GL043809.Peer reviewe

Endothelin-1-stimulated InsP₃-induced Ca²+ release is a nexus for hypertrophic signaling in cardiac myocytes

Ca(2+) elevations are fundamental to cardiac physiology-stimulating contraction and regulating the gene transcription that underlies hypertrophy. How Ca(2+) specifically controls gene transcription on the background of the rhythmic Ca(2+) increases required for contraction is not fully understood. Here we identify a hypertrophy-signaling module in cardiac myocytes that explains how Ca(2+) discretely regulates myocyte hypertrophy and contraction. We show that endothelin-1 (ET-1) stimulates InsP(3)-induced Ca(2+) release (IICR) from perinuclear InsP(3)Rs, causing an elevation in nuclear Ca(2+). Significantly, we show that IICR, but not global Ca(2+) elevations associated with myocyte contraction, couple to the calcineurin (CnA)/NFAT pathway to induce hypertrophy. Moreover, we found that activation of the CnA/NFAT pathway and hypertrophy by isoproterenol and BayK8644, which enhance global Ca(2+) fluxes, was also dependent on IICR and nuclear Ca(2+) elevations. The activation of IICR by these activity-enhancing mediators was explained by their ability to stimulate secretion of autocrine/paracrine ET-1