Researchers Reveal Changes in Temporal Inequality of Precipitation Extremes Due to Anthropogenic Forcings

Extreme precipitation events have profound impact on the hydrological cycle and are very likely to cause floods. Therefore, the assessment, detection and attribution of extreme precipitation events is a hot research topic. At present, attribution studies of extreme precipitation events tend to focus on trend changes and spatial distribution, with relatively few changes in temporal distribution, and quantitative assessment methods need to be further strengthened and developed.

Based on observation data and CMIP5/6 data (HIS, ALL, NAT simulations), scientists from Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences adopted the Gini coefficient and extreme precipitation indicators to develop a new extreme precipitation change detection and attribution method (RAI and RFI index). Then, the method was used to quantitatively evaluate the impact of human activities on regional extreme precipitation events in China.

Results show that a positive anthropogenic influence on the temporal inequality is found for precipitation extremes over China, especially in southern regions during the period 1961-2005. Projections of future for precipitation indices except R95p have a stepped upward trend in temporal precipitation variability with increasing anthropogenic forcing in most regions of China under SSP370 and SSP585 scenarios. The uniformity of extreme precipitation in Northwest China will continue to increase, suggesting an increasing risk of extreme precipitation events in future.

In addition, the extreme rainfall events also need to comprehensively consider the effects of atmospheric circulation and monsoon. Results obtained from this study offer insights into temporal variability of precipitation extremes, enrich the basic theory for the diagnosis and attribution of extreme precipitation events, and help policy makers for managing water-related disasters.

The research results titled "Changes in temporal inequality of precipitation extremes over China due to anthropogenic forcings" was published by npj Climate and Atmospheric Science.

Article link: https://www.nature.com/articles/s41612-022-00255-5 

Maps of the best temporal RFI estimates