Redai dili (Mar 2023)
Variation Characteristics and Correlation between Vegetation Phenology and Extreme Precipitation in Indo-China Peninsula
Abstract
The Indo-China Peninsula lies in a tropical monsoon climate zone and is prone to extreme weather events, including droughts and floods. Against the backdrop of global warming, the frequent occurrences of extreme precipitation affect the typical growth and phenology of vegetation. Based on the Sen+Mann-Kendall method and grey correlation analysis, the temporal and spatial characteristics of vegetation phenology and extreme precipitation in the Indo-China Peninsula and their relationships are analyzed. Vegetation phenological indices are extracted from MCD12Q2 and include the start of the growing season (SGS), the end of the growing season (EGS), and the length of the growing season (LGS). Based on the rescaled range (R/S) analysis, the future trends of these three phenological indices are predicted. The results show the following: 1) Spatial and temporal distribution characteristics: From 2001 to 2018, the SGS and EGS in the eastern region occurred earlier than those in the western region, and LGS was related to vegetation type, lasting approximately 3-7 months in agricultural areas and around 8-9 months in other areas. Excluding the number of rainstorm days (R50), the spatial distribution characteristics of extreme precipitation index were similar to that of annual total precipitation (PRCPTOT), which was higher in the west and lower in the east; 2) Trend: The SGS and EGS show an advanced trend, while the LGS shows a shortened trend; PRCPTOT and daily precipitation intensity had no obvious changes, maximum daily precipitation, extremely heavy rainfall, and R50 show a downward trend, while moderate rain days, heavy rain days and continuous wet days show an upward trend; these demonstrate that the Indo-China Peninsula has fewer extremely strong precipitation events, increased moderate intensity extreme events, and longer duration of rainfall events; 3) Correlation: By comparing the grey correlation degree between phenological indices and extreme precipitation indices, the distribution of the main extreme precipitation indices were obtained and found to have similar and concentrated spatial distribution; the spatial characteristic shows that there was a close relation between vegetation phenology and regional climate; the Indo-China Peninsula is divided into three zones from north to south, and the main controlling factors are the absolute index, the relative index, and the persistence index, respectively; 4) Sustainability: Based on the coupling analysis of H index of phenological indices calculated by R/S method and the Sen+Mann-Kendall method, we found that the future trend of phenological indicators was delayed and opposite to the previous trend in most parts of the Indo-China Peninsula. It is necessary to further study the index system and refine extreme precipitation events to distinguish the effects of different events on vegetation phenology.
Keywords
