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Polar Climates, Clouds, and Seasonality in the Paleogene

古近纪的极地气候、云层和季节性

基本信息

批准号：
9312104
负责人：
Lisa Sloan
金额：
$ 7.57万
依托单位：
University of California-Santa Cruz
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1993
资助国家：
美国
起止时间：
1993-05-01 至 1997-04-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9312104&HistoricalAwards=false
关键词：
Polar Climates Clouds Seasonality Paleogene

项目摘要

Climatic records show that polar regions have demonstrated an amplified response to global climate change through geologic time. Additionally, polar regions have significant influence upon global climate processes and conditions. Clouds also have been cited repeatedly as a critical factor in climatic change. The early Eocene appears to have been a time of warm polar conditions, but climate modeling efforts have been unsuccessful in reproducing these conditions. To date, Eocene seasonality characteristics reconstructed from proxy data have been unsatisfactorily explained by model scenarios of high atmospheric pCO2 or by warm high latitude ocean surface temperatures. However, proxy data interpretations may be explained by the presence of warming clouds at high latitudes. We have hypothesized that polar stratospheric ice clouds may have occurred in the early Eocene and produced a dampened seasonal cycle at high latitudes. Here we propose to test this hypothesis by using an atmospheric general circulation model to test the sensitivity of high latitude climates to the presence of such polar clouds. Of paramount interest will be temperature seasonality of polar climates with and without such clouds. We will examine the polar cloud mechanism for both poles, thereby testing the cloud influence on a water-covered pole surrounded by land masses and on a continentally-capped pole surrounded by ocean.

气候记录显示，极地地区已经证明了在地质时期对全球气候变化的反应被放大。此外，极地地区对全球气候变化有重大影响。气候过程和条件。云也被引用作为气候变化的关键因素。早期始新世似乎是一个温暖的极地环境，气候模拟的努力并没有成功地重现了以下条件到目前为止，始新世的季节性特征从代理数据重建的解释并不令人满意高大气pCO2模式情景或暖高纬度海洋表面温度。然而，代理数据解释可能是由于暖云的存在在高纬度地区。我们假设极地平流层冰云可能发生在始新世早期，高纬度地区的季节性周期减弱。在这里，我们建议测试这一假设通过使用大气环流模式来测试高纬度气候对这样的极地云。最重要的是温度有或没有这种云的极地气候的季节性。我们将检查两极的极地云机制，从而测试云层对被水覆盖的极点的影响，大陆块和被海洋包围的大陆覆盖的极点。