Abstract
As the largest hydroelectric projects worldwide, the Three Gorges Dam
(TGD) affects local precipitation because of the changes of hydrological
cycle caused by the impounding and draining of the TGD. However, the
influencing characteristics of the TGD on local precipitation remain
elusive. In this study, we used precipitation anomaly data derived from
long time-series grid precipitation datasets between 1988 and 2017 to
understand the changes of precipitation caused by the TGD between 2
epochs, before and after the construction of the TGD (i.e., 1988–2002
and 2003–2017), in the Three Gorges Reservoir Area (TGRA). Results
showed that the annual and dry season precipitation anomaly in the TGRA
showed an increasing trend, and the flood season precipitation anomaly
showed a slight decrease. After the impoundment of the TGD, the
precipitation concentration degree in the TGRA was decreased, indicating
that the precipitation became increasingly uniform, and the
precipitation concentration period was insignificantly increased. An
obvious resonance phenomenon between the monthly average water level and
precipitation anomaly occurred in the TGRA after 2011 and showed a
positive correlation. Our findings excavated the change of local
precipitation characteristics before and after the impoundment of the
TGRA and proved that this change had a close relationship with the water
level.