ABSTRACT
Diurnal variations in amount, frequency and intensity of warm-season hourly precipitation (HP) at seven levels, which are
defined as HP
0
.
1, 0.5, 1, 5, 10, 20 and 50 mm, are revealed based on no less than 30 years of hourly rain-gauge observations
at national stations over central and eastern China (CEC). This study investigates the variations, relationships, di
ff
erences and
similarities of total, stratiform, convective and extreme HP over the entire CEC and various subregions. Results indicate that
the variations in the amount and frequency of HP at the seven levels over the entire CEC all display a bimodal feature. For
various regions, the variations of total HP mostly feature two peaks, while convective HP mainly occurs in the late afternoon
and determines the diurnal variation of total HP intensity. On the basis of the primary peak time periods of HP frequency
at all levels over di
ff
erent subregions, the variations can be classified into three main categories: late-afternoon primary
peak, nocturnal primary peak, and time-shifting primary peak. However, the variations over some coastal regions like the
Liaodong Peninsula, the Shandong Peninsula, and the coastal regions of Guangdong, distinctly di
ff
er from those over their
corresponding larger regions. Overall, the normalized diurnal variation amplitude of amount and frequency increases with
the increasing HP intensity; convective precipitation can be represented by HP
10 mm; and the intensity of HP
50 mm is
slightly larger during the nighttime than during the daytime over the entire CEC. In northern China, diurnal variation in HP
5 mm can represent well that in convective precipitation