We analysed gross primary productivity (GPP), total ecosystem respiration (TER) and the resulting net ecosystem exchange (NEE) of carbon dioxide (CO₂) by the terrestrial biosphere during the summer of 2018 through observed changes across the Integrated Carbon Observation System (ICOS) network, through biosphere and inverse modelling, and through remote sensing. Highly correlated yet independently-derived reductions in productivity from sun-induced fluorescence, vegetative near-infrared reflectance, and GPP simulated by the Simple Biosphere model version 4 (SiB4) suggest a 130–340 TgC GPP reduction in July–August–September (JAS) of 2018. This occurs over an area of 1.6 × 10⁶ km² with anomalously low precipitation in northwestern and central Europe. In this drought-affected area, reduced GPP, TER, NEE and soil moisture at ICOS ecosystem sites are reproduced satisfactorily by the SiB4 model. We found that, in contrast to the preceding 5 years, low soil moisture is the main stress factor across the affected area. SiB4’s NEE reduction by 57 TgC for JAS coincides with anomalously high atmospheric CO₂ observations in 2018, and this is closely matched by the NEE anomaly derived by CarbonTracker Europe (52 to 83 TgC). Increased NEE during the spring (May–June) of 2018 (SiB4 −52 TgC; CTE −46 to −55 TgC) largely offset this loss, as ecosystems took advantage of favourable growth conditions.

This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale’.

我们通过观察整个综合碳观测系统的变化，分析了2018年夏季陆地生物圈的总初级生产力（GPP），总生态系统呼吸（TER）以及由此产生的二氧化碳净生态系统交换（NEE）（CO ₂）（ ICOS）网络，生物圈和逆模型以及遥感技术。由阳光诱导的荧光，植物性近红外反射率和GPP的高度相关但独立派生的生产率降低，以及由简单生物圈模型版本4（SiB4）模拟的GPP表明，七月至八月至九月（JAS）降低了130-340 TgC GPP ）在2018年。这发生在1.6×10 ⁶ km ^2的区域西北和中欧的降水异常少。在这个干旱地区，通过SiB4模型令人满意地再现了ICOS生态系统场所的GPP，TER，NEE和土壤水分减少。我们发现，与前五年相比，低土壤湿度是整个受灾地区的主要压力因素。SiB4对JAS的NEE降低了57 TgC ，这与2018年异常高的大气CO ₂观测值相吻合，这与CarbonTracker Europe得出的NEE异常（52至83 TgC）非常匹配。由于生态系统利用了有利的生长条件，2018年春季（5月至6月）的NEE增加（SiB4 -52 TgC； CTE -46至-55 TgC）在很大程度上弥补了这一损失。

本文是主题问题``欧洲2018年严重干旱和热浪的影响：从站点到大陆范围的影响''的一部分。