报告题目: Disentangling natural and anthropogenic controls on terrestrial evapotranspiration and

                  vegetation growth trends

报 告 人:  Dr. Jiafu MAO

单       位: Environmental Sciences Division and Climate Change Science Institute, Oak Ridge

                  National Laboratory, Oak Ridge, TN, USA

时       间: 2016年6月30日（周四）14:30

地       点: 大气所40号楼319会议室

Two recent studies on how natural and anthropogenic forcings influenced the global land evapotranspiration

(ET) and the northern-extratropical latitudes (NEL) vegetation growth will be presented.

During 1982-2011, the climate impacts were characterized to determine the spatiotemporal variations in ET.

Globally, rising CO₂ ranked second after the predominant climatic influences, and yielded decreasing trends

in canopy transpiration and ET, especially for tropical forests and high-latitude shrub land. Increasing

nitrogen deposition slightly amplified global ET via enhanced plant growth. Land-use-induced ET responses,

albeit with substantial uncertainties across the factorial analysis, were minor globally, but pronounced locally,

particularly over regions with intensive land-cover changes. This ET study highlights the importance of

employing multi-stream ET and ET-component estimates to quantify the strengthening anthropogenic

fingerprint in the global hydrologic cycle.

We have used multiple estimates from remote sensing-based datasets and simulations from earth system

models, and one statistical framework to attribute the enhanced NEL vegetation growth during the past three

decades. Our findings reveal that the observed vegetation activity is consistent with the simulations with

anthropogenic forcings, where the greenhouse gase forcing plays a dominant role, but not with that expected

from internal climate variability and natural forcings only. This study provides clear evidence of a discernible

 human fingerprint on large-scale terrestrial vegetation dynamics.

                欢迎大家踊跃参加和讨论!