Effect of ENSO on the annual precipitation anomaly in Guanzhong Basin and southern Shaanxi China

Abstract

East Asia has a unique geographic location, a vast territory, complex terrain, and a large population. In recent decades, the frequency of climatic oscillations in East Asia has increased, and many factors affect the climate of East Asia, with El Niño and the Southern Oscillation (ENSO) serving as one of the most important factors. In this study, through the collection and collation of 50 years’ worth of meteorological data for southern Shaanxi and central Shaanxi, the characteristics of climate change in these regions is analysed since 1951, and the correlation between precipitation, drought conditions, and ENSO is evaluated. Results show that the rainfall in the study region during an El Niño year is less than that of a ENSO neutral year, often triggering extremely dry weather. Moreover, the rainfall in a La Niña year is increased compared an ENSO neutral year, confirming that ENSO does affect the rainfall through “teleconnections”. Furthermore, given that the Qinling Mountain tectonic belt serves to diminish the ENSO signal, a large difference in rainfall exists between the foothills in the south and those to the north of the Qinling Mountains. The response mechanism in the north and south regions of Qinling Mountains acting on ENSO is consistent, indicating that the blockage effect of the Qinling Mountains on water vapour is strong related to low-level airflow. Through this research, we can begin to understand the physical mechanisms behind this phenomenon it in the central region of China and how we can effectively improve China’s short-term climate predictions. Such knowledge is tremendously important to China’s national livelihood and long-term economic development.