Detection, mapping, and interpretation of the main drivers of the Arctic GPP change from 2001 to 2019

Vegetation growth and carbon fixation in terrestrial ecosystems are seriously affected by climate. It is especially true in the Arctic due to the amplifying climate warming. This study aims to comprehend the response mechanism of the Arctic gross primary productivity (GPP) to different climatic factors such as temperature, precipitation, and fractional snow cover (FSC). First, the distribution and interannual variation of meteorological factors in the past two decades were investigated. Then, their contributions to GPP variation and dependence on elevation, latitude, and vegetation types were analyzed at different temporal scales. Finally, the time-lag effects of GPP response to meteorological factors were also explored on a monthly scale. The results show that temperature has the strongest impact on GPP, FSC follows, and precipitation ranks last. The positive response of GPP to temperature does not show time lag effects in most areas, and the negative response to precipitation displays time lags in approximately half of the Arctic regions. For FSC, the positive effects on GPP present more than 2 months lags, while the negative effects show at most a 1-month lag. The response of GPP to meteorological factors shows dependence on temporal scales. The change of GPP on the monthly scale mainly depends on the spatial distribution of these meteorological factors. On the annual scale, GPP is also affected by the interannual change of these meteorological factors. This study holds important significance in enhancing our understanding of how the carbon cycle within the Arctic terrestrial ecosystem responds to climate change.