Vegetation Productivity Slowdown on the Tibetan Plateau Around the Late 1990s

Abstract

AbstractTibetan Plateau (TP) has experienced a slowdown of the vegetation greening since the late 1990s. This structural change (i.e., greening) along with canopy physiology (i.e., potential photosynthetic productivity) regulates vegetation gross primary productivity (GPP). However, it remains unclear how the joint regulation influences the trend of alpine GPP under climate change. Here, we validate a universal productivity model against flux‐based and satellite‐derived observations at TP and diagnose the long‐term climatic impacts on GPP via canopy physiology and structure. We found an increasing but weakening trend of GPP after 1998. About 3/4 of this slowdown was attributed to the slowing greening after 1998, which was caused by the fact that the stress of atmospheric aridity and reduced benefits of warming overwhelmed the positive effects of CO2 fertilization and radiation enhancement. This study highlights the coupling between canopy structure and productivity for the long‐term period.