To what extent are changes in flood magnitude related to changes in
precipitation extremes?
Abstract
Despite increasing evidence of intensification of extreme precipitation
events associated with a warming climate, the magnitude of extreme river
flows is decreasing in many parts of the world. To better understand the
range of relationships between precipitation extremes and floods, we
analyzed annual precipitation extremes and flood events over the
Contiguous United States from 1980 to 2014. A low spatial correlation
(less than 0.2) between changes in precipitation extremes and changes in
floods was found, attributable to a weak causal relationship. The
co-variation between precipitation extremes and floods is also
substantially low, with a majority of catchments having a coefficient of
determination of less than 0.5, even among the catchments with a
relatively strong causal relationship. The findings indicate a need for
more investigations into causal mechanisms driving a non-linear response
of floods to intensified precipitation extremes in a warming climate.