Evaluation of extreme precipitation in the Yangtze River Delta Region of
China using a 1.5 km mesh convection‑permitting regional climate model
Abstract
Realistic representation of detailed rainfall characteristics on local
scale by current state-of-the-art climate models remains a key
challenge, especially on sub-daily timescales. In this research, the
convection-permitting Weather Research and Forecasting (WRF) model
configured with 1.5 km grid spacing is used to simulate precipitation on
sub-daily timescales over the Yangtze River Delta Region of China for
continuous 10 years (2005–2014). The simulations are compared to rain
gauge observations, reanalysis data, and the simulations of a lower
resolution WRF with 9 km grid spacing that has a parameterization of
convection. The results show that precipitation over the region can be
well captured by using the convection-permitting model (CPM).
Furthermore, the intensity, duration and coverage of these precipitation
events can be more accurately described by the CPM. On the convection
timescales of 1–4 hours, especially for heavy rainfall events, the CPM
is more accurate than the convection-parameterized model in capturing
the short-duration events, which may be related to its better account of
physical processes related with the convection on the
convection-permitting scale. In addition, the extreme events which are
more localized and with short-duration can be represented better by the
CPM while the convection-parameterized model tends to produce widespread
precipitation events covering more grid cells than observed. Biases of
the simulation by the 9-km mesh convection-parameterized mode appear to
be related to the deficiencies in the representation of convections.