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全球临界土壤湿度值的植物水应激
Zheng Fu1,2, Philippe Ciais3, Jean-Pierre Wigneron4
1Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China. fuzheng@igsnrr.ac.cn.
Nature communications
|June 6, 2024
概括
科学家在全球范围内绘制了关键土壤湿度值 (θcrit),发现它的平均值为0.19 m3/m3. 这一门表明植物何时经历水压,这对于气候和粮食安全预测至关重要.
科学领域:
- 环境科学环境科学
- 生态生态学 生态生态学
- 气候科学是气候科学.
背景情况:
- 在干旱期间降低土壤水分 (SM) 会导致植物水应激,因为它限制了蒸发转化.
- 临界SM值 (θcrit) 定义了水应力开始的点.
- 准确的θcrit量化对于气候,水资源,粮食生产和生态系统脆弱性预测至关重要.
研究的目的:
- 为了生成一个基于观察的全球地图的关键土壤湿度值 (θcrit).
- 评估地球系统模型在模拟 θcrit 的性能.
- 确定影响 θcrit 的关键驱动因素,并分析水应激天的趋势.
主要方法:
- 在干旱期间对陆地表面温度,日间振幅 (dLST) 和SM的综合卫星观测.
- 经过验证的卫星数据与来自流量塔的现场测量.
- 利用可解释的机器学习来识别 θcrit 的驱动因素.
主要成果:
- 确定了全球平均0.19米/米的度,其变化范围从0.12米/米 (干旱) 到0.26米/米 (潮湿) 的生态系统.
- 地球系统模型倾向于在干旱地区高估 θcrit,在潮湿地区低估它.
- 在过去的40年里,每年缺水日数量有所增加.
- 干旱度指数,叶面积和土壤质地被确定为 θcrit 的最有影响力的驱动因素.
结论:
- 观察到的全球 θcrit 模式反映了植物适应水的可用性和大气需求的情况.
- 这些发现凸显了改善地球系统模型中水应激开始的必要性.
- 该研究为确定土壤湿度临界点和了解生态系统脆弱性提供了关键数据集.
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