Climate-Driven Variability and Trends in Plant Productivity Over Recent Decades Based on Three Global Products.
Climate-Driven Variability and Trends in Plant Productivity Over Recent Decades Based on Three Global Products.
复制标题
DOI：
10.1029/2020gb006613
复制
发表时间：
2020-12
影响因子：
5.2
通讯作者：
Buermann W
中科院分区：
文献类型：
--
作者：
O'Sullivan M;Smith WK;Sitch S;Friedlingstein P;Arora VK;Haverd V;Jain AK;Kato E;Kautz M;Lombardozzi D;Nabel JEMS;Tian H;Vuichard N;Wiltshire A;Zhu D;Buermann W
气候变化对植被生产力(总初级生产力；GPP)有很大影响，因此对土地碳汇有很大影响。然而，不存在对全球GPP的直接观测，估计依赖于在不同空间和时间尺度上受观测约束的模型。在这里，我们评估了持续30多年的全球产品的GPP一致性；两种基于观测的方法，即FLUXNET站点观测(FLUXCOM)和遥感派生的光利用效率模型(RS-LUE)的放大尺度，以及一套陆地生物圈模型(TRENDYv6)。在地方尺度上，我们发现这些产品之间的年度GPP具有很高的相关性，热带和高北纬地区除外。在更长的时间尺度上，这些产品在58%的土地上就趋势的方向达成了一致，在变暖趋势的推动下，北纬地区的趋势出现了大幅增长。此外，热带地区GPP的年际变化最大，热带雨林和热带稀树草原都有很大的贡献。稀树草原GPP的可变性可能主要是由水的可获得性驱动的，尽管温度可能通过土壤水分-大气反馈发挥作用。然而，对于热带森林的规模和可变性的驱动因素没有达成共识，这表明过程表述和基本观测中的不确定性仍然存在。这些结果强调，有必要对全球初级生产力进行更直接的长期观测，并在代表性不足的区域(例如热带森林)扩大现场网络。这种能力将有助于更好地验证模型中的相关过程，更准确地估计全球生产总值。1982-2016年期间的气候变化增加了全球范围内的全球生产总值，北纬热带大草原和热带森林是全球生产总值中全球气候变化的热点，尽管在评估的产品中，主要的气候驱动因素并不一致，DGVMS系统地低估了热带森林中全球生产总值的IAV，突出了改进参数/公式的必要性
Variability in climate exerts a strong influence on vegetation productivity (gross primary productivity; GPP), and therefore has a large impact on the land carbon sink. However, no direct observations of global GPP exist, and estimates rely on models that are constrained by observations at various spatial and temporal scales. Here, we assess the consistency in GPP from global products which extend for more than three decades; two observation‐based approaches, the upscaling of FLUXNET site observations (FLUXCOM) and a remote sensing derived light use efficiency model (RS‐LUE), and from a suite of terrestrial biosphere models (TRENDYv6). At local scales, we find high correlations in annual GPP among the products, with exceptions in tropical and high northern latitudes. On longer time scales, the products agree on the direction of trends over 58% of the land, with large increases across northern latitudes driven by warming trends. Further, tropical regions exhibit the largest interannual variability in GPP, with both rainforests and savannas contributing substantially. Variability in savanna GPP is likely predominantly driven by water availability, although temperature could play a role via soil moisture‐atmosphere feedbacks. There is, however, no consensus on the magnitude and driver of variability of tropical forests, which suggest uncertainties in process representations and underlying observations remain. These results emphasize the need for more direct long‐term observations of GPP along with an extension of in situ networks in underrepresented regions (e.g., tropical forests). Such capabilities would support efforts to better validate relevant processes in models, to more accurately estimate GPP. Changes in climate over the period 1982–2016 have increased GPP at a global scale and across northern latitudes Savannas and tropical forests are hotspots for IAV in GPP, although the dominant climate drivers are not consistent among the assessed products DGVMs systematically underestimate the IAV of GPP in tropical forests, highlighting the need for improved parameterizations/formulations