Spring greening has been widely observed across the Northern Hemisphere (NH) using a remotely sensed vegetation index (e.g., the normalized difference vegetation index, NDVI). However, there is still a debate on the ecological effects of spring greening on seasonal carbon and water budgets. This study jointly investigated the concurrent and lagged effects of spring greening on carbon gain (gross primary productivity, GPP) and water loss (evapotranspiration, ET) in the summer-active ecosystems at mid and high latitudes of NH using remote sensing and multimodel ensemble data during 1982–2013. The results showed that the collective promotion of spring greening to concurrent GPP and ET is widespread despite variations in magnitude and significance. Both beneficial and adverse lagged effects of spring greening on summer GPP commonly appear with an obvious spatial heterogeneity and difference among climate-plant types. However, the expected significant suppression of spring greening to summer GPP was rarely observed even in the areas where spring ET was significantly promoted by spring greening. Nevertheless, when drought was taken into account, the response patterns of spring water use to spring greening varied to some extent, and the adverse lagged effect of spring greening to summer GPP appeared or strengthened in some regions, especially during the years with dry summer. Given the predicted warming of the climate and more frequent climatic extremes, the adverse effect of spring greening should be given more attention.

中文翻译：

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春季绿化对整个北半球季节性碳增加和水分流失的并发和滞后影响

使用遥感植被指数（例如，归一化差异植被指数，NDVI）已在北半球 (NH) 中广泛观察到春季绿化。然而，关于春季绿化对季节性碳和水收支的生态影响仍存在争议。本研究利用遥感和多模式集合数据，共同研究了春季绿化对北半球中高纬度夏季活跃生态系统碳增加（总初级生产力，GPP）和水分流失（蒸散，ET）的并发和滞后影响。 1982-2013 年期间。结果表明，春季绿化对同时发生的 GPP 和 ET 的集体促进是普遍的，尽管幅度和意义存在差异。春季绿化对夏季GPP的有利和不利滞后效应普遍存在，且在气候-植物类型之间具有明显的空间异质性和差异性。然而，即使在春季绿化显着促进春季ET的地区，也很少观察到春季绿化对夏季GPP的显着抑制。但考虑到干旱，春季水分利用对春季绿化的响应模式存在一定差异，部分地区尤其是夏季干旱年份，春季绿化对夏季GPP的不利滞后效应出现或加强。鉴于预计的气候变暖和更频繁的极端气候，应更加关注春季绿化的不利影响。然而，即使在春季绿化显着促进春季ET的地区，也很少观察到春季绿化对夏季GPP的显着抑制。但考虑到干旱，春季水分利用对春季绿化的响应模式存在一定差异，部分地区尤其是夏季干旱年份，春季绿化对夏季GPP的不利滞后效应出现或加强。鉴于预计的气候变暖和更频繁的极端气候，应更加关注春季绿化的不利影响。然而，即使在春季绿化显着促进春季ET的地区，也很少观察到春季绿化对夏季GPP的显着抑制。但考虑到干旱，春季水分利用对春季绿化的响应模式存在一定差异，部分地区尤其是夏季干旱年份，春季绿化对夏季GPP的不利滞后效应出现或加强。鉴于预计的气候变暖和更频繁的极端气候，应更加关注春季绿化的不利影响。春季水分利用对春季绿化的响应模式存在一定差异，部分地区尤其是夏季干旱年份春季绿化对夏季GPP的不利滞后效应出现或加强。鉴于预计的气候变暖和更频繁的极端气候，应更加关注春季绿化的不利影响。春季水分利用对春季绿化的响应模式存在一定差异，部分地区尤其是夏季干旱年份春季绿化对夏季GPP的不利滞后效应出现或加强。鉴于预计气候变暖和更频繁的极端气候，春季绿化的不利影响应引起更多关注。