GIScience & Remote Sensing (Dec 2022)

Global Assessment of Cumulative and Time-Lag Effects of Drought on Land Surface Phenology

  • Ronglei Zhou,
  • Yangyang Liu,
  • Mengying Cui,
  • Jinxin Lu,
  • Haijing Shi,
  • Hanyu Ren,
  • Wei Zhang,
  • Zhongming Wen

DOI
https://doi.org/10.1080/15481603.2022.2143661
Journal volume & issue
Vol. 59, no. 1
pp. 1918 – 1937

Abstract

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Increased frequency and intensity of droughts under climate change will have a significant impact on land surface phenology, however, the drought-phenology interactions that are associated with complex temporal effects are not well understood. This study examined the response of land surface phenology to drought cumulative and time-lag effects by using the standardized precipitation and evapotranspiration index (SPEI) and explored the influence of hydrothermal and plant physiological factors on the phenology-drought relationship. We used the maximum correlation (rmax-cml) between phenology and cumulative SPEI (1- to 12-month) to determine the cumulative effect. The maximum correlation (rmax-lag) between phenology and lagged SPEI (1-month) was utilized to analyze the time-lag effect. Overall, the cumulative effect affected 25.36% of the vegetated area at the start of the growing season (SOS), 26.43% of the end of the growing season (EOS), and 26.57% of the length of the growing season (LOS). SOS was negatively affected by long-term SPEI, whereas EOS and LOS had positive correlations with short-term SPEI. The rmax-cml for shrubland was the largest, and the SOS and LOS response time scales of the forest were the shortest. The rmax-cml was larger in arid and semi-arid (AR and SAR) than in humid and semi-humid (HU and SHU). Meanwhile, the response time scales were longer in HU and SHU than in AR and SAR. The time-lag effect had a larger area of impact on land surface phenology than the cumulative effect, the areas were 46.12%, 47.93%, and 50.45% for SOS, EOS, and LOS, respectively, and the lagged time scales were longer. The phenology-SPEI correlation was dominantly driven by hydrological conditions, and the time scales were mainly affected by thermal factors. Moreover, the onset of phenology and the growth/senescence rate of plants influenced the relationship, suggesting that hydrothermal conditions may shift the time of phenology by regulating the growth/senescence rate and may thus modulate the phenology–drought interaction.

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