• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >A spatially distributed model of methane emissions from Arctic tundra calculated from remotely sensed images and field data.
【24h】

A spatially distributed model of methane emissions from Arctic tundra calculated from remotely sensed images and field data.

机译：根据遥感图像和现场数据计算得出的北极苔原甲烷排放的空间分布模型。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Atmospheric methane concentration more than doubled over the last 200 years, after varying by less than 30% during the previous 10,000 years. In the past two decades the rate of this increase declined. To understand both the long-term increase in atmospheric methane, and its recent slowdown, more information about sources and sinks of atmospheric methane is required. Arctic tundra is a significant source of atmospheric methane, but the magnitude of this source is uncertain. Much of the uncertainty arises from the extrapolation of methane-emission measurements from field studies to large areas of tundra. For the present study, a spatially distributed approach for modeling methane emission from arctic tundra in the Toolik Lake area was developed. A regression tree that predicted methane-emission rates from values of environmental variables was developed from field measurements. The rules from this tree were used to combine images of environmental variables derived from ERS-1 SAR data, SPOT multispectral data, and a digital elevation model into an image of methane emission typical of the peak of the emission season. The average instantaneous methane-emission rate from the study area was estimated by the model to be 11 mg m{dollar}sp{lcub}-2{rcub}{dollar} d{dollar}sp{lcub}-1{rcub}{dollar}. This estimate is lower than some previous estimates of methane-emission from the North Slope of Alaska. The regression tree and images of environmental variables were also combined with annual methane-emission estimates to generate an image of annual methane emissions. The average annual methane-emission rate from the study area was estimated by the model to be 780 mg m{dollar}sp{lcub}-2{rcub}{dollar} yr{dollar}sp{lcub}-1{rcub}{dollar}. Annual methane emission from global tundra was estimated to be 12.2 Tg yr{dollar}sp{lcub}-1{rcub}{dollar} with uncertainty greater than 1 Tg yr{dollar}sp{lcub}-1{rcub}{dollar}.
机译：在过去的10,000年中，变化不超过30％之后，过去200年中的大气甲烷浓度增加了一倍以上。在过去的二十年中，这种增长的速度下降了。为了了解大气甲烷的长期增加及其最近的放缓，需要更多有关大气甲烷的来源和汇的信息。北极冻原是大气中甲烷的重要来源，但其来源尚不确定。大部分不确定性是由甲烷排放量测量值从实地研究外推到苔原的大面积地区引起的。对于本研究，开发了一种空间分布的方法，用于对Toolik湖地区的北极冻原甲烷排放进行建模。根据现场测量结果，开发出了根据环境变量值预测甲烷排放速率的回归树。使用该树中的规则将来自ERS-1 SAR数据，SPOT多光谱数据和数字高程模型的环境变量图像组合成典型的排放季节峰值的甲烷排放图像。该模型估计研究区域的平均瞬时甲烷排放量为11 mg m {dollar} sp {lcub} -2 {rcub} {dollar} d {dollar} sp {lcub} -1 {rcub} {美元}。该估算值低于阿拉斯加北坡甲烷排放量的先前估算值。回归树和环境变量图像还与年度甲烷排放量估算值结合在一起，以生成年度甲烷排放量图像。该模型估计研究区的年平均甲烷排放速率为780 mg m {dollar} sp {lcub} -2 {rcub} {dollar} yr {dollar} sp {lcub} -1 {rcub} {美元}。全球苔原的年甲烷排放量估计为12.2 Tg yr {dollar} sp {lcub} -1 {rcub} {dollar}，不确定性大于1 Tg yr {dollar} sp {lcub} -1 {rcub} {dollar} 。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号