School of Earth and Sustainability, Northern Arizona University, P.O. Box 4099, Flagstaff, AZ, 86011-5694, USA.
Woods Hole Research Center, Falmouth, MA, 02540, USA.
Sci Rep. 2019 Feb 26;9(1):2758. doi: 10.1038/s41598-019-39373-1.
The ability to accurately predict ecosystem drought response and recovery is necessary to produce reliable forecasts of land carbon uptake and future climate. Using a suite of models from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we assessed modeled net primary productivity (NPP) response to, and recovery from, drought events against a benchmark derived from tree ring observations between 1948 and 2008 across forested regions of the US and Europe. We find short lag times (0-6 months) between climate anomalies and modeled NPP response. Although models accurately simulate the direction of drought legacy effects (i.e. NPP decreases), projected effects are approximately four times shorter and four times weaker than observations suggest. This discrepancy between observed and simulated vegetation recovery from drought reveals a potential critical model deficiency. Since productivity is a crucial component of the land carbon balance, models that underestimate drought recovery time could overestimate predictions of future land carbon sink strength and, consequently, underestimate forecasts of atmospheric CO.
准确预测生态系统对干旱的响应和恢复能力对于预测陆地碳吸收和未来气候至关重要。本研究使用多尺度综合与陆地模型比较计划（MsTMIP）的一整套模型，根据美国和欧洲森林地区 1948 年至 2008 年的树木年轮观测结果，评估了模型模拟的净初级生产力（NPP）对干旱事件的响应以及对干旱事件的恢复情况。我们发现气候异常与模型模拟的 NPP 响应之间的滞后时间很短（0-6 个月）。尽管模型能够准确模拟干旱遗留效应的方向（即 NPP 下降），但预测的效应比观测结果显示的要短四倍且弱四倍。这种观测到的和模拟的植被从干旱中恢复之间的差异表明模型存在潜在的关键缺陷。由于生产力是陆地碳平衡的关键组成部分，因此低估干旱恢复时间的模型可能会高估未来陆地碳汇强度的预测，并因此低估大气 CO 的预测。
