Simple indices of global climate variability and change Part II: attribution of climate change during the twentieth century

Five simple indices of surface temperature are used to investigate the influence of anthropogenic and natural (solar irradiance and volcanic aerosol) forcing on observed climate change during the twentieth century. These indices are based on spatial fingerprints of climate change and include the global-mean surface temperature, the land-ocean temperature contrast, the magnitude of the annual cycle in surface temperature over land, the Northern Hemisphere meridional temperature gradient and the hemispheric temperature contrast. The indices contain information independent of variations in global-mean temperature for unforced climate variations and hence, considered collectively, they are more useful in an attribution study than global mean surface temperature alone. Observed linear trends over 1950–1999 in all the indices except the hemispheric temperature contrast are significantly larger than simulated changes due to internal variability or natural (solar and volcanic aerosol) forcings and are consistent with simulated changes due to anthropogenic (greenhouse gas and sulfate aerosol) forcing. The combined, relative influence of these different forcings on observed trends during the twentieth century is investigated using linear regression of the observed and simulated responses of the indices. It is found that anthropogenic forcing accounts for almost all of the observed changes in surface temperature during 1946–1995. We found that early twentieth century changes (1896–1945) in global mean temperature can be explained by a combination of anthropogenic and natural forcing, as well as internal climate variability. Estimates of scaling factors that weight the amplitude of model simulated signals to corresponding observed changes using a combined normalized index are similar to those calculated using more complex, optimal fingerprint techniques.     

Geologie des Gebietes zwischen Yünnanfu und dem Yangtse-Kiang (Nord-Yünnan,China)

Ohne ZusammenfassungDie Arbeit erscheint im Ann. Rep. Geol. Surv. Kwangtung & Kwangsi, Canton, China.     

Die Tektonik der Scholle von Kudowa

Zusammenfassung Die jungsaxonischen Störungen der Kudowaer Kreidescholle, insbesondere ihre tektonischen Ränder, sind durch Querverwerfungen stellenweise gegliederte Flexuren. Sie folgen zum Teil nachweislich, zum Teil wahrscheinlich jungvariscischen Verwerfungen, deren Verlauf durch Strukturzüge der kaledonischen Gebirgsbildung und der variscischen Intrusion vorgezeichnet ist. Der Bewegungssinn der vertikalen Schollenverschiebungen verkehrte sich in der südlichen Randfuge der Innersudetischen Mulde schon in variscischer Zeit, im Bereich der Kudowaer Scholle erst mit Einsetzen der jungsaxonischen Tektonik. Bei deren Ablauf war ein tangentialer Schub von NNW und ihm zugeordnet ein Ausweichen in östlicher bis südöstlicher Richtung wirksam. Damit lebte der Gebirgsdruck der kaledonischen Zeit im gleichen Sinne aber in sehr abgeschwächter Form wieder auf, während in der variscischen Tektonik lokal bedingte vertikale Ausgleichsbewegungen vorherrschten.     

Fortschritte der Ölgeologie

Ohne Zusammenfassung     

Alaska in den Jahren 1911, 1912

Ohne Zusammenfassung     

Ein Hilfsmittel zur Einführung in das Studium der Geologie

Ohne Zusammenfassung     

Der Geologische Atlas der Vereinigten Staaten von Nord-Amerika

Ohne Zusammenfassung     

V p/V s-ratios from the central Kolbeinsey Ridge to the Jan Mayen Basin,North Atlantic; implications for lithology,porosity and present-day stress field

The horizontal components from twenty Ocean Bottom Seismometers deployed along three profiles near the Kolbeinsey Ridge, North Atlantic, have been modelled with regard to S-waves, based on P-wave models obtained earlier. Two profiles were acquired parallel to the ridge, and the third profile extended eastwards across the continental Jan Mayen Basin. The modelling requires a thin (few 100 m) layer with very high V _p/V _s-ratio (3.5–9.5) at the sea-floor in the area lacking sedimentary cover. The obtained V _p/V _s-ratios for the remaining part of layer 2A, 2B, 3 and upper mantle, correspond to the following lithologies: pillow lavas, sheeted dykes, gabbro and peridotite, respectively. All crustal layers exhibit a decreasing trend in V _p/V _s-ratio away-from-the-axis, interpreted as decreasing porosity and/or crack density in that direction. A significant S-wave azimuthal anisotropy is observed within the thin uppermost layer of basalt near the ridge. The anisotropy is interpreted as being caused by fluid-filled microcracks aligned along the direction of present-day maximum compressive stress, and indicates crustal extension at the ridge itself and perpendicular-to-the-ridge compression 12 km off axis. Spreading along the Kolbeinsey Ridge has most likely been continuous since its initiation ca. 25 Ma: The data do not suggest the presence of an extinct spreading axis between the Kolbeinsey Ridge and the Aegir Ridge as has been proposed earlier. The V _p/V _s-ratios found in the Jan Mayen Basin are compatible with continental crust, overlain by a sedimentary section dominated by shale.