Testing paleogeographic controls on a Neoproterozoic snowball Earth. Geophys

• Main Authors: Christopher J. Poulsen, Robert L. Jacob, Raymond T. Pierrehumbert, Tran T. Huynh
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2002
• Subjects: Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.467.1010; http://www.earth.lsa.umich.edu/paleoclimate/pdfs/Poulsen et al.-GRL-2002.pdf

[1] The distribution of continents during the Neoproterozoic has been hypothesized to play an important role in the initiation of an ice-covered Earth. In this study, the influence of paleogeography on the Neoproterozoic climate is evaluated using a fully coupled ocean-atmosphere general circulation model (FOAM). Three simulations were completed with different continental distributions. Each simulation included a reduced solar luminosity (93 % of present-day) and low atmospheric CO2 (140 ppmv). Model results indicate that a low-latitude concentration of continents leads to lower tropical temperatures, through reduced receipt of shortwave radiation and a smaller tropical greenhouse effect, but does not significantly affect high-latitude temperatures or sea-ice extent. In contrast, the presence of snow-covered, mid- and high-latitude continents increases the sensible heat transport over the ocean, giving rise to sea-surface cooling, deep-water formation, and an advanced sea-ice margin. Nonetheless, an ice-covered Earth is not simulated in these experiments. INDEX TERMS: 3344