Abstract. The Yangtze River valley (YRV) experiences large intraseasonal and
interannual precipitation variability, which is mainly due to East Asian
monsoon influence. The East Asian monsoon is caused by interaction of many
processes in the coupled land–atmosphere–ocean system. To better understand
YRV precipitation variability in this complex system, we have studied the
precipitation moisture sources and their connection to YRV precipitation. We
obtained the moisture sources by using the European Centre for Medium-Range
Weather Forecasts' (ECMWF) ERA-Interim reanalysis
dataset, the FLEXible PARTicle dispersion model (FLEXPART), and the WaterSip
moisture source diagnostic. The variability of moisture sources reflects the
variability of YRV precipitation. Intraseasonal variations of moisture
sources include a shift of the most important source regions as the monsoon
progresses. Interannual variability of the moisture sources shows that
sources which are less important climatologically are closely connected to
variations of the driest and wettest years. Our results show that land
directly contributes 58 % of moisture for YRV precipitation
during 1980–2016, whereas the ocean contributes 42 % in direct transport.
While the importance of the ocean as a moisture source is often emphasized,
our results underscore the importance of the process of continental recycling
and the role of land moisture sources.