Abstract:

Based on NDVI remote sensing data and meteorological data of Jiangsu from 2001 to 2022, aiming at exploring the impact of extreme climate events on vegetation in Jiangsu, the paper calculated 18 extreme climate indices and employed the methods including Sen’s trend analysis, Mann-Kendall (MK) test, R/S analysis, and Pearson correlation to analyze the spatio-temporal characteristics of extreme climate and vegetation changes, as well as their response relationships. The results showed that: (1) from 2001 to 2022, the annual maximum NDVI in Jiangsu exhibited a fluctuating downward trend, with a spatial pattern of ‘higher in the north and lower in the south’; over the 22-year period, 18.50% of the area in province experienced extremely significant degradation, while 9.62% showed extremely significant improvement; in the future, 51.70% of the region might degrade. (2) In Jiangsu, both extreme high and low temperatures had intensified, with the magnitude of change in warm indices being greater than that in cold indices; the rate of daytime changes was higher than nighttime changes; extreme precipitation showed an overall increasing trend, with greater increases in the south compared to the central and northern regions. (3) NDVI and extreme temperature warm indices were mainly positively correlated in areas along the Huaihe River and to its north, while negative correlations dominated south of the Huaihe River; for cold indices, negative correlations were observed along the Yangtze River and the eastern coastal areas to the north of the river, whereas positive correlations prevailed in the central-western and southeastern coastal regions to the north of the Yangtze River; NDVI and extreme precipitation indices were mainly negatively correlated, with negative correlation areas exceeding 50%. In a word, the relationship between extreme climate and vegetation growth shows significant spatial heterogeneity, providing a scientific support for ecological conservation, vegetation restoration, and climate adaptation management in Jiangsu.

Key words: NDVI, extreme climate, spatio-temporal change, Hurst index, Jiangsu