|
|
Spracklen, D.V.; Arnold, S.R.; Sciare, J.; Carslaw, K.S.; Pio, C. (2008). Globally significant oceanic source of organic carbon aerosol. Geophysical research letters, 35.
Keywords: organic carbon; ocean; aerosol; 0305 Atmospheric Composition and Structure: Aerosols and particles; 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 0312 Atmospheric Composition and Structure: Air/sea constituent fluxes
Programme: 414;415
|
|
|
|
Francia, P.; Lanzerotti, L.J.; Villante, U.; Lepidi, S.; Di Memmo, D. (2005). A statistical analysis of low-frequency magnetic pulsations at cusp and cap latitudes in Antarctica. J. Geophys. Res., 110.
Keywords: polar cap and cusp pulsations; magnetospheric wave guide modes; field line resonances; open/closed field line boundary; 2784 Magnetospheric Physics: Solar wind/magnetosphere interactions; 2740 Magnetospheric Physics: Magnetospheric configuration and dynamics; 2776 Magnetospheric Physics: Polar cap phenomena; 2706 Magnetospheric Physics: Cusp; 2752 Magnetospheric Physics: MHD waves and instabilities
Programme: 1130
|
|
|
|
Ciais, P.; Manning, A.C.; Reichstein, M.; Zaehle, S.; Bopp, L. (2007). Nitrification amplifies the decreasing trends of atmospheric oxygen and implies a larger land carbon uptake. Global biogeochemical cycles, 21.
Keywords: carbon cycle; nitrogen cycle; oxygen; 0330 Atmospheric Composition and Structure: Geochemical cycles
Programme: 439
|
|
|
|
. (2005). On the seasonal asymmetry of the diurnal and semidiurnal geomagnetic variations. J. Geophys. Res., 110.
Abstract: The diurnal and semidiurnal variations of the geomagnetic field are investigated at 18 observatories using long series of hourly values (up to 97 years at Sitka). The seasonal variations of amplitude of the 12-hour and 24-hour lines are obtained for the H and Z components using a 28-day sliding window. The Fourier analysis is performed using either all days within the window or only the five quietest days. At midlatitudes a strong lack of symmetry about the summer solstice is observed for both lines and both components. This effect is enhanced when selecting quiet days. When averaged over the entire series, the sign of this seasonal asymmetry is the same at 9 out of 10 midlatitude observatories for both lines and for a given component; it is opposite for the H and Z components. Such a coherent seasonal asymmetry is not found at low and high latitudes. At high latitudes a strong annual variation is found inside the polar caps, while a strong semiannual variation is found in the auroral zones. When selecting quiet days, these two effects are weaker, and the seasonal asymmetry becomes comparable to that at midlatitudes. At all latitudes the year-to-year variations of the seasonal asymmetry are uncorrelated with solar activity. It is suggested that lower thermospheric winds may have a similar seasonal asymmetry between spring and autumn equinoxes. Such an asymmetry is present in the published literature but has been overlooked. Possible causes for this wind asymmetry are reviewed.
Keywords: daily variation; lower thermospheric winds; ionospheric dynamo; current system; geomagnetic activity; equinoxes; 1555 Geomagnetism and Paleomagnetism: Time variations: diurnal to decadal; 2437 Ionosphere: Ionospheric dynamics; 3369 Atmospheric Processes: Thermospheric dynamics; 3389 Atmospheric Processes: Tides and planetary waves
Programme: 139
|
|
|
|
. (2007). Reviews of geophysics, 45.
Keywords: history; geomagnetism; paleomagnetism; 1599 Geomagnetism and Paleomagnetism: General or miscellaneous; 1714 History of Geophysics: Geomagnetism and paleomagnetism; 5440 Planetary Sciences: Solid Surface Planets: Magnetic fields and magnetism; 7999 Space Weather: General or miscellaneous; 9820 General or Miscellaneous: Techniques applicable in three or more fields
Programme: 139
|
|
|
|
. (2002). High-resolution Holocene N2O ice core record and its relationship with CH4 and CO2. Global biogeochemical cycles, 16.
Abstract: Nitrous oxide (N2O) concentration records exist for the last 1000 years and for time periods of rapid climatic changes like the transition from the last glacial to today's interglacial and for one of the fast climate variations during the last ice age. Little is known, however, about possible N2O variations during the more stable climate of the present interglacial (Holocene) spanning the last 11 thousand years. Here we fill this gap with a high-resolution N2O record measured along the European Project for Ice Coring in Antarctica (EPICA) Dome C Antarctic ice core. On the same ice we obtained high-resolution methane and carbon dioxide records. This provides the unique opportunity to compare variations of the three most important greenhouse gases (after water vapor) without any uncertainty in their relative timing. The CO2 and CH4 records are in good agreement with previous measurements on other ice cores. The N2O concentration started to decrease in the early Holocene and reached minimum values around 8 ka (<260 ppbv) before a slow increase to its preindustrial concentration of ?265 ppbv.
Programme: 960
|
|
|
|
. (2008). Ground-based measurements of spatial and temporal variability of snow accumulation in East Antarctica. Reviews of geophysics, 46.
Abstract: The East Antarctic Ice Sheet is the largest, highest, coldest, driest, and windiest ice sheet on Earth. Understanding of the surface mass balance (SMB) of Antarctica is necessary to determine the present state of the ice sheet, to make predictions of its potential contribution to sea level rise, and to determine its past history for paleoclimatic reconstructions. However, SMB values are poorly known because of logistic constraints in extreme polar environments, and they represent one of the biggest challenges of Antarctic science. Snow accumulation is the most important parameter for the SMB of ice sheets. SMB varies on a number of scales, from small-scale features (sastrugi) to ice-sheet-scale SMB patterns determined mainly by temperature, elevation, distance from the coast, and wind-driven processes. In situ measurements of SMB are performed at single points by stakes, ultrasonic sounders, snow pits, and firn and ice cores and laterally by continuous measurements using ground-penetrating radar. SMB for large regions can only be achieved practically by using remote sensing and/or numerical climate modeling. However, these techniques rely on ground truthing to improve the resolution and accuracy. The separation of spatial and temporal variations of SMB in transient regimes is necessary for accurate interpretation of ice core records. In this review we provide an overview of the various measurement techniques, related difficulties, and limitations of data interpretation; describe spatial characteristics of East Antarctic SMB and issues related to the spatial and temporal representativity of measurements; and provide recommendations on how to perform in situ measurements.
Keywords: surface mass balance; East Antarctica; measurements; ground-truthing; 0762 Cryosphere: Mass balance; 0726 Cryosphere: Ice sheets; 0794 Cryosphere: Instruments and techniques; 9310 Geographic Location: Antarctica; 1621 Global Change: Cryospheric change
Programme: 411;454
|
|
|
|
Garcia, S.; Angelier, J.; Bergerat, F.; Homberg, C.; Dauteuil, O. (2008). Influence of rift jump and excess loading on the structural evolution of northern Iceland. Tectonics, 27.
Keywords: rift jump; structural evolution; lava dip; dyke; fault; flexure zone; Iceland; 8010 Structural Geology: Fractures and faults; 8036 Structural Geology: Paleoseismology; 8178 Tectonophysics: Tectonics and magmatism; 8137 Tectonophysics: Hotspots, large igneous provinces, and flood basalt volcanism; 9325 Geographic Location: Atlantic Ocean
Programme: 316
|
|
|
|
Magand, O.; Genthon, C.; Fily, M.; Krinner, G.; Picard, G.; Frezzotti, M.; Ekaykin, A.A. (2007). J. Geophys. Res., 112.
Keywords: surface mass balance; East Antarctica; data quality; 0762 Cryosphere: Mass balance; 9310 Geographic Location: Antarctica; 0736 Cryosphere: Snow; 0776 Cryosphere: Glaciology; 0794 Cryosphere: Instruments and techniques
Programme: 411;454
|
|
|
|
. (2007). Mantle upwellings and convective instabilities revealed by seismic tomography and helium isotope geochemistry beneath eastern Africa. Geophysical research letters, 34.
Keywords: anisotropy tomography; helium isotope data; Africa; 8121 Tectonophysics: Dynamics: convection currents, and mantle plumes; 7270 Seismology: Tomography; 1040 Geochemistry: Radiogenic isotope geochemistry; 7208 Seismology: Mantle; 9305 Geographic Location: Africa
Programme: 133;906
|
|
