School of Biological Sciences, University of Utah, Salt Lake City, UT 84112;
School of Biological Sciences, University of Utah, Salt Lake City, UT 84112.
Proc Natl Acad Sci U S A. 2019 Jul 9;116(28):14071-14076. doi: 10.1073/pnas.1904747116. Epub 2019 Jun 24.
The fluxes of energy, water, and carbon from terrestrial ecosystems influence the atmosphere. Land-atmosphere feedbacks can intensify extreme climate events like severe droughts and heatwaves because low soil moisture decreases both evaporation and plant transpiration and increases local temperature. Here, we combine data from a network of temperate and boreal eddy covariance towers, satellite data, plant trait datasets, and a mechanistic vegetation model to diagnose the controls of soil moisture feedbacks to drought. We find that climate and plant functional traits, particularly those related to maximum leaf gas exchange rate and water transport through the plant hydraulic continuum, jointly affect drought intensification. Our results reveal that plant physiological traits directly affect drought intensification and indicate that inclusion of plant hydraulic transport mechanisms in models may be critical for accurately simulating land-atmosphere feedbacks and climate extremes under climate change.
陆地生态系统的能量、水和碳通量会对大气产生影响。陆地-大气反馈会加剧严重干旱和热浪等极端气候事件，因为土壤湿度降低会减少蒸发和植物蒸腾作用，同时会增加局部温度。在这里，我们结合了温带和北方地区涡度协方差塔网络、卫星数据、植物特征数据集和一个机械植被模型的数据，来诊断土壤湿度对干旱的反馈控制。我们发现，气候和植物功能特征，特别是与最大叶片气体交换率和植物水力连续体中水分传输相关的特征，共同影响干旱的加剧。我们的结果表明，植物生理特征直接影响干旱的加剧，并表明在模型中纳入植物水力传输机制对于准确模拟气候变化下的陆地-大气反馈和气候极端事件可能是至关重要的。
