The dramatic retreat of Mount Kenya’s glaciers between 1963 and 1987: greenhouse forcing

Author:

Hastenrath Stefan,Kruss Phillip D.

Abstract

The retreat of the glaciers on Mount Kenya is quantitatively well documented for the intervals 1899–1963 and 1963–1987. The ice recession between 1899 and 1963 was strongly dependent on solar radiation geometry. By contrast, the ice thinning between 1963 and 1987 amounted to about 15 m for all glaciers regardless of topographic location. This suggests that climatic forcings other than solar radiation have become more prominent. Sensitivity analyses indicate that the energy supply of about 5 W m−2, required to produce the observed ice thinning through melting, can be accounted for by a combination of climatic forcings. The direct effect of changing atmospheric composition (“greenhouse effect”) on the net longwave radiation could have contributed less than 1 W m−2. A warming of 0.0 to 0.2°C would translate into an additional downward-directed sensible heat transfer of 0.0 to 1.4 W m−2. A 0.1 to 0.2 g kg−1 increase in specific humidity would, through savings in the latent heat transfer, contribute 2 to 4 W m−2. Long-term station records show little warming trend for East Africa itself. However, mid-tropospheric specific humidity trends of about 0.6 g kg−1 over the past two decades in the equatorial belt have been reported in the literature, and considered to be consequences of “global warming” and the “greenhouse effect”. Viewed in perspective, the ice wastage on Mount Kenya between 1963 and 1987 appears to have been driven primarily by three climatic forcings, conceivably all steered by the “greenhouse effect”: a direct forcing through the net longwave radiation; an indirect forcing through warming and therefore enhanced sensible heat transfer; and another indirect forcing through warming (not necessarily in the region itself), leading to increased (advected) atmospheric moisture, and hence to reduced latent heat transfer, this last line of control being the most important.

Publisher

International Glaciological Society

Subject

Earth-Surface Processes

Cited by 56 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3