Diurnal variations of rainfall affected by complex topography based on high-density observation in Chongqing over southwest China

Abstract

Located in the eastern edge of the Sichuan Basin (SCB) in the southwest China, Chongqing is a mountainous region with typical complex topographic features. Using the hourly rainfall observation data of high-density 1686 meteorological stations in Chongqing during warm season from 2009 to 2016, we investigated the diurnal characteristics of precipitation affected by complex topography. The complex mountainous terrain has a significant impact on diurnal variations and distinct regional features of rainfall amount, frequency, and intensity. The stations located in the higher complex mountainous areas have greater rainfall amount, frequency, and intensity than those in the lower surrounding areas. In addition, the detailed characteristics of the rainfall amount and frequency in the four study regions further show that the rainfall amount and frequency significantly increase with the rise of elevation, especially in the area that terrain height sharply increases along the mountain extending direction. The diurnal variation of the rainfall amount is characterized by a bimodal structure with a dominant early-morning peak occurring at approximately 0700 LST (23 UTC) and a weaker secondary late-afternoon peak at approximately 1600 LST (08 UTC), while the rainfall frequency has a single early-morning peak. The terrain height has a significant impact on the proportions of the early-morning rainfall. With the elevation increasing in the four study regions, the proportions of rainfall amount (frequency) that occurs during early-morning period decrease.

Comparison of Various Rainfall Erosivity Formulas in the Application of USLE for Erosion Cases in Indonesia

“…The rain erosivity factor represents the capacity/ability of rainfall to peel off and transport soil particles downstream [11]. Many formulas are available to calculate the R-factor [12,13,14,15,16,17,18,19,20]. Those formulas emerged as the high variability of the rainfall characteristics in one place to another.…”

Role of Topography in Triggering Elevated Thunderstorms Associated With Winter Cold Fronts Over the Eastern Yunnan‐Guizhou Plateau

“…From the perspective of the dynamic mechanism of terrain, features of mountainous topography, including elevation, relief amplitude, slope, and aspect, and the airflow intensity, strike, and stability can be used to determine the location of CI (Houze, 2012; Q. Li et al., 2022). The most common dynamic mechanisms are lifting and blocking of the terrain, which depend mainly on the nondimensional ratio U / Nh , where U is the air flow intensity perpendicular to the mountain, N is the Brunt–Väisälä frequency, and h is the maximum terrain height (Houze, 2012).…”

“…In the cold season, because of the weak solar radiation, local thermal distinction and diurnal variation are not significant; therefore, there is far less convection in the cold season than in the warm season (Geerts et al., 2017; Reif & Bluestein, 2017). Most previous studies have focused either CI in the warm season (Behrendt et al., 2011; Kang et al., 2019; Q. Li et al., 2022; Rao et al., 2022; Wulfmeyer et al., 2011) or elevated convection occurring in relatively simple terrains (He et al., 2018; Y. Zhang, Xue, et al., 2019, F. Zhang et al., 2021), with few on cold‐season elevated CI associated with a remarkable topographic gradient. M. Ma et al.…”

“…The YGP is located in the southwest of China, with an altitude of more than 2000 m (Figure 1a). Derived from the complex terrain in southwestern China, weather stations are rare in the YGP, the observational data are sparse (Q. Li et al., 2022). The Wushan‐Dalou Mountains run from the northeast to southwest of the terrain, connecting the provinces of Hubei, Chongqing, and Guizhou.…”

“…From the perspective of the dynamic mechanism of terrain, features of mountainous topography, including elevation, relief amplitude, slope, and aspect, and the airflow intensity, strike, and stability can be used to determine the location of CI (Houze, 2012;Q. Li et al, 2022).…”