Primary data of: Spring phenology rather than climate dominates the trends in peak of growing season in the Northern Hemisphere

Shifts in plant phenology regulate ecosystem structure and function, which
feeds back to the climate system. However, drivers for the peak of growing
season (POS) in seasonal dynamics of terrestrial ecosystems remain
unclear. Here, spatial-temporal patterns of POS dynamics were analyzed by
solar-induced chlorophyll fluorescence (SIF) and vegetation index in the
Northern Hemisphere over the past two decades from 2001 to 2020. Overall,
a slow advanced POS was observed in the Northern Hemisphere, while a
delayed POS was distributed mainly in northeastern North America. Trends
of POS were driven by the start of growing season (SOS) rather
than pre-POS climate, both at hemisphere and biome scale. The effect of
SOS on the trends in POS was the strongest in shrublands while the weakest
in evergreen broad-leaved forests. These findings highlight the crucial
role of biological rhythms rather than climatic factors in exploring
seasonal carbon dynamics and global carbon balance.

植物物候的变化调控着生态系统的结构与功能，而这又会反馈至气候系统。然而，陆地生态系统季节动态中生长季峰值（peak of growing season, POS）的驱动因素仍不明确。本研究利用太阳诱导叶绿素荧光（solar-induced chlorophyll fluorescence, SIF）与植被指数，分析了2001至2020年过去二十年间北半球POS动态的时空格局。总体而言，北半球观测到POS缓慢提前的趋势，而POS延迟的区域主要分布在北美东北部。无论是在半球尺度还是生物群落尺度，POS的变化趋势均由生长季始期（start of growing season, SOS）而非POS前期气候驱动。SOS对POS变化趋势的影响在灌丛中最强，而在常绿阔叶林中最弱。这些发现强调，在探究季节碳动态与全球碳平衡时，生物节律而非气候因素扮演着关键角色。