Diurnal cycle of precipitation over Fujian Province during the pre-summer rainy season in southern China

Abstract

Precipitation diurnal cycle over Fujian in the presummer rainy season has been revealed based on the hourly rain gauge data during [2009][2010][2011][2012][2013]. The precipitation amount (PA) over northwestern Fujian and most southeast coasts shows relatively small diurnal variability. This is in contrast to large diurnal variations in the mountainous areas. Regional differences in precipitation diurnal cycles are obviously noted among the coastal, valley, hilly, and mountainous areas. The precipitation diurnal cycles are significantly affected by the terrain elevation and distance to coast, PA and precipitation frequency (PF) show much more pronounced double diurnal peaks with the terrain elevation and distance to coast increased. However, the precipitation intensity (PI) basically shows one distinct late afternoon diurnal peak for different elevations and distances to coast. Four typical patterns of precipitation diurnal cycle are further identified by cluster analysis. The four typical PF patterns show relatively apparent morning peaks over coasts, inland mountains, and hills in addition to distinct late afternoon maxima. Low PF with weak diurnal amplitude is mainly located over the coastal areas, while high PF with strong diurnal amplitude is found over the valley, hilly, and mountainous regions. The PA exhibits a weak early morning peak and a relatively strong late afternoon peak over coastal, hilly, or mountainous areas and windward slopes but only one distinct late afternoon peak over the valley regions and leeward slopes. The amplitude of PA diurnal cycle is the weakest over the coastal areas but the strongest over the valley regions or leeward slopes among the four PA patterns. The four PI diurnal cycle patterns consistently show distinct afternoon peaks.

Diurnal variation of precipitation from the perspectives of precipitation amount, intensity and duration over Sumatra from rain gauge observations

“…For all elevations, the diurnal variation of three parameters has one dominant peak. There is no apparent increase in the number of peaks with an increase in altitude, as observed in China (Zhang et al ., 2017). The most remarkable signal of topographic influence is the change of amplitude of PA and PF's diurnal variation (Figure 6).…”

“…Correlations of terrain height with PA, PF, and PI, are 0.10, 0.25, and 0.24, respectively, indicating a slight increase of the three parameters with increasing elevation. However, these correlations are not significant and much weaker than those found in other regions such as China (Zhang et al ., 2017; Li et al ., 2019).…”

“…Following Zhang et al . (2017), the PA is defined as the accumulated precipitation divided by the number of hours of available data. Furthermore, the PF is defined as the ratio of total 10‐min having measurable precipitation above a threshold of 0.2 mm rainfall to the total 10‐min of available data.…”

Characteristics of the Precipitation Diurnal Variation and Underlying Mechanisms Over Jiangsu, Eastern China, During Warm Season

“…Many recent studies have revealed that the diurnal variations of precipitation over eastern China are strongly influenced by the East Asia monsoon and topographic contrast. Over southeastern China, the spatial distributions of precipitation diurnal cycles in midsummer are primarily dependent on topography (Chen et al, 2010;Zhang et al, 2017;Wu et al, 2018). Over Shandong Province of eastern China, the precipitation over the inland areas strengthens in the afternoon due to the sea breeze, which may enhance the afternoon peak of precipitation.…”

“…The precipitation diurnal peak in the afternoon appears earlier in the coastal northern plain than in the central northern plain (Zhuo et al, 2014). Over Fujian Province of southeastern China, the precipitation diurnal cycles are different among the coastal, valley, hilly, and mountainous areas during pre-summer (Zhang et al, 2017). The precipitation diurnal variation over Taiwan in the warm season is the result of local forcing involving solar thermal heating and island-scale land-sea breezes interacting with orography (Chen et al, 2012;Huang and Wang, 2014;Huang and Chang, 2018).…”