资源环境科技发展态势分析平台

Novel precipitation event data sets are created by tracking 3-hourly observed rainfall in both time and space in the TRMM 3B42 and ERA-Interim data sets. Relative to TRMM, ERA-Interim data undersimulate the total number of events (factor of approximate to 0.5), and oversimulate the frequency of events lasting >5days (factor of 1.6). Longer-lasting events tend to have larger spatial footprints and higher intensity precipitation at any point in their lifetime, and thus contribute significantly more to total precipitation than shorter events. Precipitation changes in selected tropical and subtropical regions are attributed to different event characteristics: some to changes in event rainfall intensity, others to changes in the number of events. In the 40 degrees S-40 degrees N spatial average, the number of events lasting 1-5 days significantly increased from 1998 to 2014 in both the TRMM 3B42 and ERA-Interim data. The event data sets, analysis scripts, and selected processed data are freely available online.

Plain Language Summary Personal experience tells us that rain occurs in individual events, yet when researchers study rainfall in observations and models we do not tend to focus on event characteristics. Our work aims to change this, by presenting an analysis of event characteristics for all rain events that happened between 40 degrees S and 40 degrees N from 1980 to 2015. We look at how long events last (as they move through space), the average spatial footprint, or size, of events, and how much rain fell in total in an event. We set the stage for future work studying how total event rainfall may change in future climates, which may be crucial for estimating changes to the likelihood of flooding.