Impact of extreme climates on land surface phenology in Central Asia

Abstract

Global climate change has led to an increasing frequency and intensity of extreme climates (e.g., extreme temperature and precipitation), and its impact on land surface phenology (LSP) has attracted increasing attention. This study evaluated the effects of extreme climates on land surface phenology in Central Asia (CA) based on 13 extreme climate indices (ECIs). The results showed that the start of the season (SOS) of the LSP was gradually delayed, the end of the season (EOS) advanced, and the length of the growing season (LOS) shortened. Most ECIs showed varying degrees of an increasing trend, except the cold indices of the cool days (TX10p) and the cool nights (TN10p) and the precipitation indices of the max one-day precipitation amount (RX1day) and the max five-day precipitation amount (RX5day). The LSP was influenced by extreme climates, and 13 ECIs were mainly negatively correlated with the SOS and positively correlated with the EOS and LOS. Increased extreme temperature and decreased extreme precipitation contributed to the change in the LSP. The most important impact on the SOS was from the max Tmin (TNx), the mean Tmax (TXmean), while the mean Tmin (TNmean) and warm days (TX90p) also had noticeable effects. The most important impact on the EOS and LOS was from TX90p, followed by TX10p and TXmean. Based on climate model projections from the Coupled Model Intercomparison Project Phase 6 (CMIP6), future extreme climates are projected to intensify under Shared Socioeconomic Pathways (SSPs) and will likely continue to affect the LSP. This study helps provide a basis for formulating scientific and reasonable vegetation restoration strategies and disaster warnings in Central Asia.

Keywords

• Land surface phenology
• Extreme climate indices
• CMIP6
• Central Asia