陆地水流以透气为主导的水流
Scott Jasechko1, Zachary D Sharp, John J Gibson
1Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131, USA. jasechko@unm.edu
Nature
|April 5, 2013
概括
透汗是大陆水损失的主要驱动因素,占蒸发透汗的80-90%. 这一发现强调了改善气候模型的必要性.
科学领域:
- 水文学的水文学
- 生态生态学 生态生态学
- 气候科学 气候科学
背景情况:
- 全球淡水供应受到大陆降水,蒸发和透气的影响.
- 目前的气候模型在估计透气时面临着严重的不确定性,原因是不准确的口腔导电数据和缺乏采集区规模测量.
- 现有的全球透气估计差异很大,从20%到65%的总陆地蒸发透气.
研究的目的:
- 为了准确量化透气在陆地蒸发透气中的比例.
- 为了确定陆地植被每年透过的水量.
- 估计全球初级生产率 (GPP) 及其与气候变化的关系.
主要方法:
- 利用透气和蒸发的不同同位素效应来区分这两种水流.
- 分析了大型湖泊和河流的全球数据集,以评估水回收.
- 使用工厂用水效率 (WUE) 比率,与碳同化相关的透气损失.
主要成果:
- 透气构成了地球大陆的主要水流,占地面总蒸发透气的80%至90%.
- 据估计,陆地植被每年回收约62,000±8,000立方公里的水到大气中.
- 这个过程消耗了大约一半的太阳能被陆地表面吸收.
- 全球总初级生产率估计为每年129±32千兆的碳,与之前的估计相一致.
结论:
- 透气是大陆水损失的主要驱动因素,明显超过了蒸发.
- 准确的水资源预测和气候模型开发应该优先考虑对生物流 (透气) 的改进模拟,而不是物理流 (蒸发).
- 这项研究提供了更可靠的全球GPP估计,并强调了透气在全球水和碳循环中的关键作用.
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