Diverging Northern Hemisphere Trends in Meteorological Versus Ecological Indicators of Spring Onset in CMIP6
Diverging Northern Hemisphere Trends in Meteorological Versus Ecological Indicators of Spring Onset in CMIP6
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DOI：
10.1029/2023gl102833
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发表时间：
2023-04
影响因子：
5.2
通讯作者：
Xiaolu Li;T. Ault;Colin P. Evans;F. Lehner;C. Carrillo;Alison Donnelly;T. Crimmins;Amanda S. Gallinat;M. D. Schwartz
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作者：
Xiaolu Li;T. Ault;Colin P. Evans;F. Lehner;C. Carrillo;Alison Donnelly;T. Crimmins;Amanda S. Gallinat;M. D. Schwartz
植物物候学调控着碳循环和陆气耦合。目前，气候模型经常与植被生长的季节性周期观测结果不一致，部分原因是衡量和模拟春季到来的方式。在这里，我们使用基于温度和叶面积指数(LAI)的指标来表征CMIP6模型中的春季开始。尽管不同模型的历史时间差异很大，但大多数人都认为，近几十年来，春天已经提前了，而且随着未来变暖，春天将继续更早到来。在北半球1950年至2014年、1981年至2014年和2015年至2099年期间，在历史和SSP5-8.5模拟中，基于热量的指标估计春季推进为−0.70±0.2、−1.4±0.4和−2.4±0.7天/十年，而基于LAI的指标估计−0.4±0.3、−0.1±0.3和−1±1.1天/十年。因此，基于LAI的指标表现出较弱的提前发病趋势，导致不同指数的不确定性与模型不确定性一样大或更大。调和这些差异对于理解春季到来的未来变化至关重要。
Plant phenology regulates the carbon cycle and land‐atmosphere coupling. Currently, climate models often disagree with observations on the seasonal cycle of vegetation growth, partially due to how spring onset is measured and simulated. Here we use both thermal and leaf area index (LAI) based indicators to characterize spring onset in CMIP6 models. Although the historical timing varies considerably across models, most agree that spring has advanced in recent decades and will continue to arrive earlier with future warming. Across the Northern Hemisphere for the periods 1950–2014, 1981–2014, and 2015–2099 in the historical and SSP5‐8.5 simulations, thermal‐based indicators estimate spring advances of −0.7 ± 0.2, −1.4 ± 0.4, and −2.4 ± 0.7 days/decade, while LAI‐based indicators estimate −0.4 ± 0.3, −0.1 ± 0.3, and −1±1.1 days/decade. Thereby, LAI‐based indicators exhibit weaker trends toward earlier onset, leading to uncertainties from different indices being as large or larger than model uncertainty. Reconciling these discrepancies is critical for understanding future changes in spring onset.