Study on Interaction between Global Warming and Permafrost Thawing

全球变暖与多年冻土融化相互作用的研究

基本信息

批准号：
14102008
负责人：
FUKUDA Masami
金额：
$ 36.61万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (S)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2006
项目状态：
已结题

项目摘要

In the Mid of Siberian Taiga, long term field measurements at disturbed and control sites on Carbon budget, heat and mass transfers were conducted. As to investigation, two observation towers were installed. Before disturbance intact Taiga forest absorbed carbon dioxide by 86mg/m^2.day, but after disturbance carbon dioxide was emitted from the ground by 140 mg/m2.day due to the loss of vegetation and increase of soil respiration. Loss of surface vegetation resulted in the increase of flux heat to the ground by 20% and it caused the large scale thawing of upper permafrost. The long term filed measurements of soil respiration by the method of open top camber indicated that the degree of soil respiration is proportional to soil temperature as well as soil moisture. The new empirical equations of these two factors were obtained. The highly concentrated methane as much as 2000 ppm was stored in the permafrost. After disturbance an additional thawing of upper permafrost resulted in the emission of stored methane to the atmosphere. Impact of permafrost disturbance under the global warming may the source of carbon dioxide and methane in Siberian permafrost area. There are three sources of green house gases induced by fire disturbance. 1) direct emission of carbon dioxide during combustion 2) at the burned site soil respiration was forced to increase by the increased soil temperature 3) in the process of permafrost thawing, stored methane was emitted to atmosphere. It may cause to the positive feedback of future global warming.

在西伯利亚Taiga中部，进行了碳预算，热和质量转移的干扰和控制位点的长期测量。至于调查，安装了两个观察塔。在干扰完整的Taiga森林之前，将二氧化碳吸收为86mg/m^2.天，但是在干扰二氧化碳后，二氧化碳在地面上散发出140 mg/m2。由于植被丧失和土壤呼吸的增加，二氧化碳。表面植被的损失导致地面的通量加热增加了20％，并导致上层冻土的大规模融化。长期通过开放顶室的方法对土壤呼吸进行了测量表明，土壤呼吸程度与土壤温度和土壤水分成正比。获得了这两个因素的新经验方程。高度浓缩的甲烷高达2000 ppm，存储在多年冻土中。干扰后，多年冻土上的额外融化导致将甲烷储存到大气中。在全球变暖下，多年冻土干扰的影响可能会在西伯利亚永久冻土区域二氧化碳和甲烷的来源。火灾干扰引起的温室气体有三种来源。 1）燃烧过程中二氧化碳的直接排放2）在燃烧的现场，土壤呼吸被迫升高土壤温度3）在多年冻结解冻的过程中，将储存的甲烷散发到大气中。这可能会导致未来全球变暖的积极反馈。