Orographic Effects of Geomorphology on Precipitation in a Pluvial Basin of the Eastern Tibetan Plateau

Abstract

The eastern Tibetan Plateau is subjected to strong spatial variations in precipitation, but the underlying reasons are still not well understood due to sparse in-situ meteorological observations. In this study, streamflow observations were adopted to investigate the orographic controls on precipitation in the Qingyijiang (QYJ) Basin of the eastern Tibetan Plateau. The method of multi-year annual water balance was used to estimate the basin-level precipitation using in-situ streamflow and flux-based evapotranspiration. In addition, elevation transect was designed to examine the possible links between precipitation and geomorphology. The results showed the severe under-estimation of regional precipitation by weather sites (~1150 mm yr−1) in the QYJ Basin, where the runoff depth was as high as ~1450 mm yr−1. The water balance revealed a much higher level of precipitation (~2000 mm yr−1) in the QYJ Basin, but precipitation in the two adjacent basins was contrastingly low (<1000 mm yr−1). The spatial pattern of precipitation was well consistent with the local horn-mouth geomorphology, with more precipitation occurring in the geomorphologically converging and elevating region. Furthermore, within the the QYJ Basin, annual precipitation was larger in the sub-basins (>2200 mm) on or near the bottom of the horn-mouth geomorphology than the others (<1800 mm). With these results, we concluded that the high precipitation level in the QYJ Basin could be attributed to the combined converging and lifting effects of geomorphology on the westward atmospheric vapor. Therefore, flooding risk should be carefully accounted for in the basins with similar geomorphology in the eastern Tibetan Plateau.

Estimation of Real-Time Rainfall Fields Reflecting the Mountain Effect of Rainfall Explained by the WRF Rainfall Fields

“…The complex topography of the Korea, with many mountainous areas, has a significant impact on the spatial pattern of rainfall. Previous studies have highlighted the importance of orographic effects on the spatial distribution of rainfall in mountainous areas [1][2][3][4][5][6][7][8]. The mountain effect, also known as the orographic effect, may cause rainfall intensification, acting as a precursor of convective storm formation [9,10].…”

Spatially differentiated changes in regional climate and underlying drivers in southwestern China

“…Many studies have shown that regions of higher elevations are more susceptible to global climate change than regions of lower elevations (Pepin et al 2015;Li et al 2020aLi et al , 2020bYou et al 2020); with increases in elevation, the annual mean temperature and precipitation generally become more variable (You et al 2020;Li et al 2020aLi et al , 2020cAguilar-Lome et al 2019;Minder et al 2018;Pepin et al 2015). Topography may affect climate through interference to lower atmospheric circulation and air-flow dynamics (Jiang 2003;Barros et al 2006;Yang and Zhang 2019;He et al 2019). Vegetation has been well recognized for playing a critical role in moderating warming effect via.…”