Human-induced climate change leads to changes in extreme precipitation regimes. Increased frequency and intensity of extreme precipitation can bring out severe flooding and have tremendous losses to agriculture, transportation, and natural ecosystem. Hence, understanding extreme precipitation regimes (e.g. frequency, intensity, timing, and interval) are urgently needed for the infrastructure design, flooding prediction, and disaster prevention and mitigation.
Variations of frequency and intensity of extreme precipitation have been fully investigated at global scales, continent scales, and national or regional scales. However, extreme precipitation response to increasing temperature includes not only changes of frequency and intensity, but also changes of extreme precipitation interval (EPIV) and the precipitation during the neighboring daily extreme precipitations interval (EPIP).These changes have not been fully evaluated yet in observations or climate model simulations although they are very useful to understand variations of extreme precipitation.
The researchers from the Northeast Institute of Geography and Agroecology of the Chinese Academy of Sciences have investigated for the first time variations of EPIV and EPIP across China and the relationships with large-scale atmospheric circulations. The study was published online in Climate Dynamics.
The researchers used daily precipitation data from 669 meteorological stations during the past five decades across China and projections of 19 general circulation models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) under two Representative Concentration Pathway (RCP) scenarios (RCP4.5 and RCP8.5) to evaluate variations of EPIV and EPIP.
The national average annual EPIV increased across China during the last five decades, while annual EPIP significantly decreased. The decreases mainly occurred in southwest China, east China, and southeast China. At national and regional scales, the average annual EPIV and EPIP showed greater decreases under the RCP8.5 scenario than those under the RCP4.5 scenario from 2006 to 2100.Annual EPIP showed a stronger correlation with extreme precipitation intensity than EPIV. The abnormal geopotential height over western Mongolia and the western Pacific at 500 hpa as well as the abnormal SSTs in Japan Sea and the western of Pacific in rainy seasons would result in abnormal annual EPIVs and EPIPs in China.
“Our results suggested that EPIP decreased across China in observations and model simulations, while EPIV exhibited different trends between observations and model simulations,we should pay more attention to the variation of EPIV in the future,” said Dr. WANG Lei.

Keywords: Extreme precipitation; Interval; Frequency; Intensity; Climate change scenarios; China

Decreasing precipitation occurs in daily extreme precipitation intervals across China in observations and model simulations

https://link.springer.com/article/10.1007/s00382-020-05120-w

WANGLei
Northeast Institute of Geography and Agroecology
E-mail: wanglei@iga.ac.cn