Asymmetric Responses of the End of Growing Season to Daily Maximum and Minimum Temperatures on the Tibetan Plateau

Climate warming has delayed the end of the growing season (EOS) in temperate and cold ecosystems. However, it is unclear whether asymmetric warming (higher warming at night than during the day) has triggered different responses in the timing of EOS. Here we used satellite-observed EOS of alpine vegetation to reveal its asymmetric responses to nighttime and daytime warming on the Tibetan Plateau. Increased preseason minimum temperature could postpone EOS by 7.92 day K⁻¹ (P < 0.01), probably by slowing low-temperature induced leaf senescence, whereas increased preseason maximum temperature could advance EOS by 3.57 day K⁻¹ (P < 0.05), likely due to the confounding effects of water limitations. The delaying effect of nighttime warming was stronger in more arid areas of the plateau, where daytime warming has a stronger advancing effect on EOS. Our results provide new insights into understanding and modeling autumn vegetation phenology on the Tibetan Plateau and grassland ecosystems in other temperate and cold regions.