Spatiotemporal changes of extreme climate indices and their influence and response factors in a typical cold river basin in Northeast China

As a consequence of global warming, extreme weather events have become much more common in many countries. Extreme weather events negatively impact on mortal social and environmental issues, and recognizing the dynamical aspects of extreme weather is absolutely essential for forecasting and mitigating the implications of extreme weather occurrences on people and the planet. This research looked at the variations in space and time of 11 extreme precipitation indices and 16 extreme temperature indices in the Liaohe River Basin within Jilin Province and their associations with normalized-difference vegetation index (NDVI) and atmospheric circulation indices were evaluated. The results showed that: (1) The extreme warmth index showed a growing pattern and the extreme coldness index showed a declining tendency. The average consecutive dry days and consecutive wet days (CWD) indices showed a slow decreasing trend, and all other extreme precipitation indices showed a slowly intensifying trend. (2) There was a favorable connection between the NDVI and the extreme climate index, and most of the NDVI showed a significant correlation with the extreme temperature index, which shows that the dominant factor causing changes in the NDVI is extreme temperature. (3) The Arctic Oscillation index has a significant effect on extreme low temperatures. The Pacific Decadal Oscillation (PDO) has a large influence on extremely high temperatures. The CWD index in the extreme precipitation index had significant negative and positive correlations with the Southern Oscillation index and the PDO index, respectively. The results of the study contribute to further understanding and forecasting of extreme weather events in the Liaohe River Basin of Jilin Province and provide insights for appropriate measures to reduce the social and environmental impacts associated with extreme weather events in the study area.