关键词: 极端干湿事件, SPEI, 时空变化, NDVI, 水稻生长, 湖北省

Abstract:

Under global climate warming, frequent extreme dry and wet events threaten crop growth, highlighting the importance of studying their impact on agricultural production for regional food security and water resource management. In this study, the Normalized Difference Vegetation Index (NDVI) was employed to assess rice growth in Hubei Province. Meteorological data spanning 1990 to 2020 from 32 stations and the Standardized Precipitation Evapotranspiration Index (SPEI) were employed to analyze spatial and temporal changes in extreme dry and wet events. Based on the NDVI from 2000 to 2020, the rice growth and its response to extreme dry and wet events were scrutinized. Correlation coefficients were computed to investigate the possible impacts on rice growth. Findings indicate a decline in extreme drought frequency, with 7 events occurring in 1990-1999, 4 in 2000-2009, and only 2 in 2010-2020. Conversely, extreme wet events numbered 5 in 1990-1999, 2 in 2000-2009, and 5 in 2010-2020, expanding in spatial extent without significant frequency change. Notably, the NDVI during the crucial growth period (June-August) exhibited a significant increase (p=0.012), growing at a rate of 0.007 8 per year, indicating improved growth conditions. Extreme dry and wet events in general exerted negative impacts on rice growth, with the coefficient of correlation between NDVI and SPEI reaching 0.418 and -0.358, respectively. To mitigate the impact of extreme dry and wet events, enhancing meteorological monitoring during rice’s critical growth phases is recommended. This proactive measure aims to bolster resilience against droughts and floods, ensuring consistent and robust agricultural production.

Key words: extreme wet and dry events, SPEI, spatio-temporal variations, NDVI, rice growth, Hubei Province