Regional moisture budget associated with drought/flood events over China

In this study, long-term (1961–2011) variations in the moisture budget and drought/flood events in six subregions of China are analyzed. Water vapor is mainly transported zonally during winter, while meridional transport is much stronger during summer. During winter, both the input moisture from the western boundary and the output moisture from the eastern boundary are slightly weakened; thus, the total amount of regional moisture in these subregions does not change much in eastern China. During summer, the decline in input moisture from the south is slightly weaker than the decrease in output moisture via the northern boundary; therefore, the net moisture budget is slightly increased in eastern China, resulting in more flood events during recent decades in this region. Generally, China tends to suffer much less drought risk and higher flood risk in the mature winter and decaying summer of El Niño; the opposite impact appears during a La Niña event, but with lower intensity.