Changes in Precipitation Extremes over the Source Region of the Yellow River and Its Relationship with Teleconnection Patterns

Feifei Yuan,Jiahong Liu,Huimin Wang,Ronny Berndtsson,Yiheng Du,Dong An,Qing Cao,Zhenchun Hao

doi:10.3390/w12040978

Abstract

Precipitation extremes and their underlying causes are important processes to understand to plan appropriate adaptation measures. This paper presents an analysis of the spatiotemporal variability and trend of precipitation extremes in the important source region of the Yellow River and explores the connection to global teleconnection patterns and the 850-mb vector wind. Six indices for precipitation extremes were computed and analyzed for assessment of a changing regional climate. Results showed that these indices have a strong gradient from the northwest to the southeast part for the period 1961–2015, due to the great influence from the south-easterly summer monsoon flow. However, no statistically significant trends were found for the defined indices at the majority of stations, and their spatial distribution are noticed by irregularly mixed positive and negative changes except for the maximum number of consecutive wet days (CWD). Singular value decomposition analysis revealed that the precipitation extreme indices—including annual total precipitation when daily precipitation >95th percentile (R95p), annual count of days with daily precipitation ≥10 mm (R10mm), annual maximum consecutive 5-day precipitation (R5d), total precipitation divided by the number of wet days (SDII), and CWD—are negatively related to the El Nino-Southern Oscillation (NINO 3.4) in the first mode, and the maximum number of consecutive dry days (CDD) is positively related to the Scandinavian pattern in the second mode at 0.05 significance level. The 850-mb vector wind analysis showed that the southwestern monsoon originating from the Indian Ocean brings sufficient moisture to this region. Furthermore, the anti-cyclone in the western part of the North Pacific plays a significant role in the transport of moisture to the source region of the Yellow River. The links between precipitation extremes and teleconnection patterns explored in this study are important for better prediction and preparedness of climatic extremes.

Highlights

The Yellow River Basin has experienced major floods and droughts that have caused devastating damages in recent years
Compared to the above five indices, the consecutive dry days (CDD) has an opposite trend. This is due to the topographical gradient of precipitation and the annual precipitation distribution being largely affected by the south-easterly summer monsoon [21]
China was mainly caused by anti-cyclonic flow in the western part of the North Pacific (WNP), connected with ENSO and ENSO Modoki events

Summary

Introduction

The Yellow River Basin has experienced major floods and droughts that have caused devastating damages in recent years. This region is more fragile and vulnerable to climate extremes due to population growth, aging infrastructure and urbanization development [1,2,3]. Precipitation extremes have increased in intensity and frequency under global warming [5,6,7], and this change has significant impact on the natural habitats of human communities in terms of property damage, loss of life and endangered species It has been a fundamental issue for the government, the public and the research community due to the disastrous consequences [8,9,10,11,12].

Methods

Results

Conclusion