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Abstract Global warming accelerates water cycle, causing more droughts globally that challenge monitoring and forecasting. The Standardized Precipitation Evapotranspiration Index (SPEI) is used to assess drought characteristics and response time of natural and economic systems at various timescales. However, existing SPEI datasets have coarse spatial or temporal resolution or limited spatial extent, restricting their ability to accurately identify the start or end dates or the extent of drought at the global scale. To narrow these gaps, we developed a global daily SPEI dataset (SPEI-GD), with a 0.25° spatial resolution from 1982 to 2021 at multiple timescales (5, 30, 90, 180 and 360 days), based on the precipitation from European Center for Medium Weather Forecasting Reanalysis V5 (ERA5) dataset and the potential evapotranspiration from Singer’s dataset. Compared to widely used SPEIbase dataset, the SPEI-GD can improve the spatial-temporal resolution and the accuracy of SPEI in areas where meteorological sites are lacking. The SPEI-GD significantly correlates with site-based SPEI and soil moisture. Our dataset solidly supports sub-seasonal and daily-scale global and regional drought research.

Grassland, the most widespread vegetation type in China, has been greening recently.However, the extent to which the greenness has been translated into productivity and the underlying mechanism of the decoupled grassland greenness and productivity remains unclear. In this study, we detected the trend of normalized difference vegetation index (NDVI) and gross primary productivity (GPP) of grassland in China from 2000 to 2019 and analyzed the driving mechanism of the inconsistency between them. It was found that the relative increase rate of productivity (27.27%, p

Abstract The mechanisms causing European heatwaves in recent years, particularly their differences among several heatwaves, are poorly understood. Here atmospheric circulation anomalies and soil moisture‐temperature coupling during the summer 2018 heatwave are comprehensively examined and compared with the 2003 and 2010 heatwaves using ERA5 reanalysis, model simulations, and eddy covariance flux measurements. We show that the 2018 heatwave successively affected northern and central Europe, and the peak temperature in Finland and northwest Russia broke historical records of the past 40 years. Although three heatwaves were all initially triggered by atmospheric circulation anomalies, the strong moisture‐temperature coupling were found to further strengthen the 2003 and 2010 heatwaves. This coupling was also strong in central Europe during 2018 heatwave, but was weak in the northern European center of the heatwaves. The high temperature in 2018 was mainly due to increases in the amount of net surface radiation caused by the clear skies associated with reduced precipitation. Furthermore, we also find that land cover plays a critical role in determining the occurrence and strength of soil moisture‐temperature coupling. Cropland/grassland depletes soil moisture more readily than forests, thereby triggering a more rapid release of sensible fluxes as observed during 2018 heatwave.