Diagnosing evapotranspiration responses to water deficit across biomes using deep learning
Diagnosing evapotranspiration responses to water deficit across biomes using deep learning
复制标题
使用深度学习诊断跨生物群落缺水的蒸散响应
DOI：
10.1111/nph.19197
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发表时间：
2023
期刊：
影响因子：
9.4
通讯作者：
Stocker, Benjamin D.
中科院分区：
文献类型：
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作者：
Giardina, Francesco;Gentine, Pierre;Konings, Alexandra G.;Seneviratne, Sonia I.;Stocker, Benjamin D.
考虑水分限制是确定植被对干旱敏感性的关键。量化水分限制对蒸散量（ET）的影响受到植被类型、气候带和垂直沿着根系带异质性的挑战。在这里，我们使用通量测量来训练深度神经网络，以研究ET对干旱条件的响应。我们确定了一个水分胁迫因子（fET），隔离ET减少大气干旱和其他协变驱动程序的影响。我们将fET与累积水分亏缺进行回归，揭示了全柱水分有效性的控制。我们发现了各种ET对水分胁迫的响应。反应范围从fET快速下降到几个萨凡纳稀树草原和草原站点的水无限速率的10%，到大多数森林的fET轻度减少，尽管存在大量的水赤字。最敏感的反应被发现在最干旱和温暖的网站。气孔和水力传导的调节和访问地下水库，无论是在地下水或深层土壤水分，可以解释不同的网站观察到的不同行为的组合。标准的陆面模型无法捕捉到这种多样的响应，这可能反映了地下水储存表示的简化。
Accounting for water limitation is key to determining vegetation sensitivity to drought. Quantifying water limitation effects on evapotranspiration (ET) is challenged by the heterogeneity of vegetation types, climate zones and vertically along the rooting zone.Here, we train deep neural networks using flux measurements to study ET responses to progressing drought conditions. We determine a water stress factor (fET) that isolates ET reductions from effects of atmospheric aridity and other covarying drivers. We regress fET against the cumulative water deficit, which reveals the control of whole‐column moisture availability.We find a variety of ET responses to water stress. Responses range from rapid declines of fET to 10% of its water‐unlimited rate at several savannah and grassland sites, to mild fET reductions in most forests, despite substantial water deficits. Most sensitive responses are found at the most arid and warm sites.A combination of regulation of stomatal and hydraulic conductance and access to belowground water reservoirs, whether in groundwater or deep soil moisture, could explain the different behaviors observed across sites. This variety of responses is not captured by a standard land surface model, likely reflecting simplifications in its representation of belowground water storage.