Observed trends in light precipitation events over global land during 1961-2010

Based on daily station precipitation data, this study investigates the trends in light precipitation events (less than the 50th percentile) over global land during 1961-2010. It is found that the frequency of light precipitation events decreases over East China (EC) and northern Eurasia (NE) but increases over the United States of America (US), Australia (AU), and the Iberian Peninsula (IP). However, the trends in the intensity of light precipitation events are opposite to those in frequency. We find that the trends in light precipitation events are possibly associated with the changes in static stability. Over EC and NE (US, AU, and IP), the static stability weakens (strengthens) during 1961-2010. The weakening (strengthening) of static stability leads to increase (decrease) in precipitation intensity due to the enhancement (reduction) of upward motion; light (relatively heavier) precipitation events accordingly shift toward relatively heavier (light) precipitation, and the frequency of light precipitation events decreases (increases) consequently.