Holocene land-cover reconstructions for studies on land cover-climate feedbacks
Holocene land-cover reconstructions for studies on land cover-climate feedbacks
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DOI：
10.5194/cp-6-483-2010
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发表时间：
2010-01-01
影响因子：
4.3
通讯作者：
Seppa, H.
中科院分区：
文献类型：
--
作者：
Gaillard, M. -J.;Sugita, S.;Seppa, H.
本文的主要目的是：(1)回顾过去十年来人类土地覆盖变化（ALCC）情景的优缺点，(2)讨论基于花粉的过去土地覆盖重建的相关问题，并介绍一种新的方法，揭示（区域估计植被丰度）从花粉数据推断过去土地覆盖的长期记录，(3)提出一个新的项目（LANDCLIM）：(4)讨论气候和植被/土地覆盖模式的意义和未来发展方向，以及通过改变反馈评估人类活动引起的土地覆盖变化对区域气候的影响。现有的ALCC情景显示它们之间存在很大差异，很少涵盖公元800年以前的时间段。当这些情景用于评估人类土地利用对气候的影响时，得到了截然不同的结果。它强调需要诸如基于reveal模型的土地覆盖重建等方法。它们可能有助于微调对过去土地覆盖的描述，并有助于更好地了解ALCC的长期变化如何影响气候。研究表明，与传统的花粉百分比方法相比，reveal模型能够更好地估算区域植被/土地覆盖的变化。这将在整个全新世的区域到大陆空间尺度上实现对土地覆盖的可靠评估。我们绘制了10种植物功能类型（PFTs）在200 BP和6000 BP的覆盖率估算图，以及从6000 BP到最近的5个时间窗的两个露天PFTs“草地”和“农业用地”的覆盖率估算图。LANDCLIM的结果有望为重新评估ALCC估计提供关键数据，以便更好地了解陆地表面-大气相互作用。
The major objectives of this paper are: (1) to review the pros and cons of the scenarios of past anthropogenic land cover change (ALCC) developed during the last ten years, (2) to discuss issues related to pollen-based reconstruction of the past land-cover and introduce a new method, REVEALS (Regional Estimates of VEgetation Abundance from Large Sites), to infer long-term records of past land-cover from pollen data, (3) to present a new project (LANDCLIM: LAND cover - CLIMate interactions in NW Europe during the Holocene) currently underway, and show preliminary results of REVEALS reconstructions of the regional land-cover in the Czech Republic for five selected time windows of the Holocene, and (4) to discuss the implications and future directions in climate and vegetation/land-cover modeling, and in the assessment of the effects of human-induced changes in land-cover on the regional climate through altered feedbacks. The existing ALCC scenarios show large discrepancies between them, and few cover time periods older than AD 800. When these scenarios are used to assess the impact of human land-use on climate, contrasting results are obtained. It emphasizes the need for methods such as the REVEALS model-based land-cover reconstructions. They might help to fine-tune descriptions of past land-cover and lead to a better understanding of how long-term changes in ALCC might have influenced climate. The REVEALS model is demonstrated to provide better estimates of the regional vegetation/land-cover changes than the traditional use of pollen percentages. This will achieve a robust assessment of land cover at regional- to continental-spatial scale throughout the Holocene. We present maps of REVEALS estimates for the percentage cover of 10 plant functional types (PFTs) at 200 BP and 6000 BP, and of the two open-land PFTs 'grassland' and 'agricultural land' at five time-windows from 6000 BP to recent time. The LANDCLIM results are expected to provide crucial data to reassess ALCC estimates for a better understanding of the land suface-atmosphere interactions.