Climate model sensitivity to changes in Miocene paleotopography
Climate model sensitivity to changes in Miocene paleotopography
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DOI：
10.1080/08120090903246170
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发表时间：
2009-01-01
影响因子：
1.2
通讯作者：
Seton, M.
中科院分区：
文献类型：
--
作者：
Herold, N.;You, Y.;Seton, M.
中新世中期气候最佳期（MMCO）发生在17 - 15Ma之间，是贯穿新生代的一系列变暖事件中的最后一次，也是自35Ma以来地球最热的一次（比中纬度地区的温度高6摄氏度）。矛盾的是，mmcco期间的CO2浓度报告的值是现今值或更低，对变暖的解释尚未确定。我们使用规定的海面温度测试了群落大气模型（CAM）和群落陆地模型（CLM）的第三版对中中新世古地形变化的敏感性。这种降低的另一个影响是削弱夏季和冬季季风，我们讨论了这种变化可能对耦合的海洋-大气模拟产生的影响。我们得出的结论是，虽然地形变化显著影响当地温度，但它们对调和地质记录得出的温度和二氧化碳测量值之间的差异几乎没有作用。
The Middle Miocene Climatic Optimum (MMCO), which occurred between 17 and 15Ma, was the last of a series of warming events to have punctuated the Cenozoic and is the warmest the planet has been since 35Ma (6 degrees C warmer than present at middle latitudes). Paradoxically, CO2 concentrations during the MMCO are reported at present-day values or less and an explanation for warming has yet to be established. We test the sensitivity of version three of the Community Atmosphere Model (CAM) and Community Land Model (CLM) to changes in Middle Miocene paleotopography using prescribed sea-surface temperatures. We create four separate global paleotopography datasets based on altered Andean and Tibetan Plateau elevations as well as changes to global sea-level. We find that the largest warming is achieved with a lowering of the Tibetan Plateau from 4700 to 2600m, resulting in a local temperature increase of up to 9 degrees Cconsistent with the modern-day lapse rate measured in Chinaand a global mean ground temperature increase of 0.5 degrees C. An additional effect of this lowering is to weaken the summer and winter monsoons, and we discuss implications such changes may have for coupled ocean-atmosphere simulations. We conclude that while changes to topography significantly affect local temperatures, they do little to reconcile the disagreement between temperature and CO2 measurements derived from the geological record.