Benutzer:Nils Simon/Klimatologie/Gletscher, Eisschilde und Polkappen
Diese Seite dient zur Sammlung von wissenschaftlichen Artikeln, die sich mit dem Zusammenspiel von globaler Erwärmung und den Eisschilden sowie den Polkappen beschäftigen. Hinzu kommt die Frage nach der Gletscherschmelze oder allgemeiner, nach dem Verhalten der Gletscher im Zuge der Erderwärmung.
Schneider et al.[Bearbeiten]
Schneider, D. P., E. J. Steig, T. D. van Ommen, D. A. Dixon, P. A. Mayewski, J. M. Jones, and C. M. Bitz (2006): Antarctic temperatures over the past two centuries from ice cores, in: Geophysical Research Letters, 33, L16707, doi:10.1029/2006GL027057
"We present a reconstruction of Antarctic mean surface temperatures over the past two centuries based on water stable isotope records from high-resolution, precisely dated ice cores. Both instrumental and reconstructed temperatures indicate large interannual to decadal scale variability, with the dominant pattern being anti-phase anomalies between the main Antarctic continent and the Antarctic Peninsula region. Comparative analysis of the instrumental Southern Hemisphere (SH) mean temperature record and the reconstruction suggests that at longer timescales, temperatures over the Antarctic continent vary in phase with the SH mean. Our reconstruction suggests that Antarctic temperatures have increased by about 0.2°C since the late nineteenth century. The variability and the long-term trends are strongly modulated by the SH Annular Mode in the atmospheric circulation."
NASA (2006): Arctic Ice Meltdown Continues With Significantly Reduced Winter Ice Cover, Feature vom 13. September, siehe online
NASA/Grace (2006): NASA Mission Detects Significant Antarctic Ice Mass Loss. News Release, 2. März
Chen et al.[Bearbeiten]
Chen, J.L., C. R. Wilson und B. D. Tapley (2006): Satellite Gravity Measurements Confirm Accelerated Melting of Greenland Ice Sheet, in: Science, online veröffentlicht am 10. August 10, Science doi:10.1126/science.1129007
"Using time-variable gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) satellite mission, we estimate ice mass changes over Greenland during the period April 2002 to November 2005. After correcting for the effects of spatial filtering and limited resolution of GRACE data, the estimated total ice melting rate over Greenland is –239 ± 23 cubic kilometers per year, mostly from East Greenland. This estimate agrees remarkably well with a recent assessment of –224 ± 41 cubic kilometers per year, based on satellite radar interferometry data. GRACE estimates in southeast Greenland suggest accelerated melting since the summer of 2004, consistent with the latest remote sensing measurements."
Bradley et al.[Bearbeiten]
Bradley, Raymond S., Mathias Vuille, Henry F. Diaz und Walter Vergara (2006): Threats to Water Supplies in the Tropical Andes, in: Science, Vol. 312, No. 5781, S. 1755 - 1756, 23. Juni, doi:10.1126/science.1128087
"Climate models predict that greenhouse warming will cause temperatures to rise faster at higher than at lower altitudes. In the tropical Andes, glaciers may soon disappear, with potentially grave consequences for water supplies."
Dyurgerov, Mark B. und Mark F. Meier (2005): Glaciers and the Changing Earth System: A 2004 Snapshot. Institute of Arctic and Alpine Research, Occasional Paper 58 (PDF)
"Glacier changes are having impacts on processes of global importance such as sea-level rise, hydrology of mountain-fed rivers, freshwater balance of oceans, and even the shape and rotation of the Earth. Here we discuss the effects of “small glaciers” — all perennial ice masses other than the Greenland and Antarctic ice sheets. We now estimate that the total area of these glaciers and ice caps to be about 785 ± 100 x 103 km2, somewhat larger than earlier estimates because of improved information on isolated glaciers and ice caps around the periphery of the large ice sheets. We estimate the total volume of this ice to be about 260 ± 65 x 103 km3, equivalent to 0.65 ± 0.16 m of sea-level rise.
Glacier mass balance data (both annual and seasonal) can be used to infer current climatic change in precipitation and temperature, and the spatial distribution of these can assist in the analysis and modeling of climate change. This is especially important in high-mountain and high-latitude areas, where precipitation data are few and biased. Air temperature increase is the major forcing of glacier change. Glacier response to recent climate warming shows a steepening mass balance gradient with altitude due to increasing ice ablation below the equilibrium line altitude, and, to a lesser extent, increasing snow accumulation above that altitude. Observational results also show increasing glacier mass turnover and mass balance sensitivity to air temperature; these changes are not predicted by existing climate/glacier models. Sensitivity and turnover have also decreased in variability starting at the end of the 1980s.
Glacier wastage caused sea level to rise at a rate of 0.51mm yr–1 for the period 1961–2003, but glaciers are now (1994-2003) causing sea level to rise 0.93mm yr–1. This freshwater addition to the oceans may be affecting ocean circulation and ocean ecosystems, and causing socio-economic impacts due to sea-level change. This contribution from glaciers is likely to continue to increase in the future. Acceleration of glacier wastage also affects other global processes, including spatial and temporal changes in the Earth’s gravitational field, Earth oblateness and rotation rate, and regional uplift.
Global acceleration of glacier volume losses has affected the freshwater cycle at many scales, from global to local. The glacier contribution to the freshwater inflow to the Arctic Ocean has been increasing, and this increase will affect many aspects of the arctic climate system. Increasing summer runoff to large Asian rivers and high-elevation glacierized watersheds in both Glacier Americas is important for agriculture and human needs, but this release of water from ice storage may diminish in the future as the relatively small high-mountain glaciers begin to disappear."
Arctic Climate Impact Assessment[Bearbeiten]
WWF (2005): An Overview of Glaciers, Glacier Retreat, and Subsequent Impacts in Nepal, India and China (PDF)
Oerlemans, Johannes Hans (2005): Extracting a Climate Signal from 169 Glacier Records, in: Science Express, 3. März, doi:10.1126/science.1107046
"A temperature history for different parts of the world has been constructed from 169 glacier length records. Using a first-order theory of glacier dynamics, changes in glacier length were related to changes in temperature. The derived temperature histories are fully independent of proxy and instrumental data used in earlier reconstructions. Moderate global warming started in the middle of the 19th century. The reconstructed warming in the first half of the 20th century is 0.5 K. This warming was remarkably coherent over the globe. The warming signals from glaciers at low and high elevations appear to be very similar."