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©2010 Elsevier, Inc. 1 Chapter 13 Cuffey & Paterson.

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Presentation on theme: "©2010 Elsevier, Inc. 1 Chapter 13 Cuffey & Paterson."— Presentation transcript:

1 ©2010 Elsevier, Inc. 1 Chapter 13 Cuffey & Paterson

2 ©2010 Elsevier, Inc. 2 FIGURE 13.1 Relation between estimated atmospheric CO2 concentration and the ice contribution to sea level, indicated by geological archives. From highest to lowest sea levels, the four points are: older than 35Myr ago (a time of no permanent ice); about 32Myr ago (after an ice sheet formed on Antarctica); the preindustrial modern world; and the Last Glacial Maximum (21 kyr ago). Adapted from Alley et al. (2005).

3 ©2010 Elsevier, Inc. 3 FIGURE 13.2 Theoretical calculation of atmospheric stationary waves and temperature anomalies generated by a northern hemisphere ice sheet (location shown in gray). Top panel: Variations of pressure at about 5 km altitude (given as equivalent height). Wind directions are approximately parallel to these contours. Bottom panel: Temperature anomaly at elevation of 1 km; southward flow causes cooling, northward flow causes warming. Adapted from Roe and Lindzen (2001).

4 ©2010 Elsevier, Inc. 4 FIGURE 13.3 Variations of ice volume over the last two million years. (a) The marine δ18O record (heavy line); low values correspond to greater ice volumes. For each major deglaciation, a thin vertical line shows the timing relative to the obliquity variations, shown along the bottom. Note the larger and longer-period fluctuations of δ18O in the second million years compared to the first. Adapted from Huybers (2007). (b) Power spectra of variability from 2 Myr to 1 Myr ago. Thin line is for rate of change of δ18O, a proxy for rate of ice volume change. Thick line is the spectrum for insolation integrated over the summer. Both show strong peaks at a 41-kyr period (frequency 0.024 kyr−1). Adapted from Huybers (2006). (c) Same as (b), but for the most recent 1Myr. The 41-kyr period remains clear, but the ice volume changes strongly at a 100-kyr period with no corresponding insolation change. Higher-frequency variations also appear in both spectra. Adapted from Huybers (2006).

5 ©2010 Elsevier, Inc. 5 FIGURE 13.4 Variation of sea level over the last 140 kyr, estimated from two independent proxies. Adapted from Chappell et al. (1996).

6 ©2010 Elsevier, Inc. 6 FIGURE 13.5 Snapshots of ice sheet evolution over the last glacial cycle, according to the model of Huybrechts (2002). (a) The Antarctic Ice Sheet. (b) The Greenland Ice Sheet. Numbers for each panel indicate the contribution to global sea-level change. Adapted from Huybrechts (2002).

7 ©2010 Elsevier, Inc. 7 FIGURE 13.6 A model hypothesis for the configuration of the Laurentide Ice Sheet at the Last Glacial Maximum. Contour labels give elevations in meters above sea level. Adapted from Tarasov and Peltier (2004). (Refer to the insert for a color version of this figure)


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