Land surface phenology and its response to climate change in the Guangdong-Hong Kong-Macao Greater Bay Area during 2001-2020

Land surface phenology (LSP), an important branch of vegetation phenology, which is sensitive to climate change and play important role in ecosystem. As a typical subtropical area, in spite of its complex vegetation structure, the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) LSP was not focused fully. Hence, In this study, a long time series LSP data from 2001 to 2020 was obtained based on MODIS normalized difference vegetation index (NDVI) using classical Savitzky-Golay filter. Subsequently, phenology spatial pattern and spatiotemporal trends and their correlation with climate change were analyzed for different vegetation types in the Guangdong-Hong Kong-Macao Greater Bay Area. The results revealed an obvious spatial heterogeneity and significant annual variation trend in vegetation phenology. The start of growing season (SOS) and the end of growing season (EOS) appeared delayed trend and the length of growing season (LOS) showed a prolonged trend, with average slope values of 0.55, 0.52 and 0.81 days per year, respectively. In general, preseason precipitation and solar radiation are the main climatic factors regulating vegetation phenology in the Greater Bay Area, and the enhancement of preseason precipitation and solar radiation is the main reason for the delay of vegetation withering and yellowing period and the extension of growing season. Ecosystems of the Greater Bay Area were mainly depending on preseason precipitation and solar radiation to regulate the leaf senescence and control plant growth duration. The present study can enhance performance of vegetation phenology models and provide useful information on ecological protection in subtropical areas.

Automated summary

In this study, long time series Land Surface Phenology (LSP) data from 2001 to 2020 of the Guangdong-Hong Kong-Macao Greater Bay Area were analyzed using MODIS NDVI. The results revealed significant spatial heterogeneity and annual variation trends in vegetation phenology, with delayed start of growing season (SOS), delayed end of growing season (EOS), and extended length of growing season (LOS). Preseason precipitation and solar radiation were identified as the main climatic factors influencing vegetation phenology in the Greater Bay Area.