Rainfall Map (IMAGE) Princeton University Caption From 1997 to 2007, rainfall became highly erratic for much of the globe, particularly in tropical areas. Green areas indicate that the day-to-day variability increased so that those areas experienced more days at one extreme or another, either dry or a downpour with little weather variation in-between. Credit David Medvigy Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.