Projection of Future Summer Precipitation over the Yellow River Basin: A Moisture Budget Perspective

Jiao Li,Zhenfei Tang,Yang Zhao

doi:10.3390/atmos11121307

Abstract

The projection of future precipitation over the Yellow River Basin (YRB) is of great importance to regional climate change adaptation and mitigation. Using the historical simulations and projections under the four combined scenarios of the shared socioeconomic pathways and the forcing levels of the Representative Concentration Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) provided by the multimodel ensemble mean of 10 models in phase six of the Coupled Model Intercomparison Project (CMIP6), the projected spatial and temporal changes of future summer precipitation over the YRB and the possible physical mechanisms underlying future summer precipitation changes are investigated. Large discrepancies in precipitation exist among the four scenarios during the latter half period of the 21st century, with precipitation under SSP5-8.5 being the largest. Nevertheless, the precipitation under each of the four scenarios shows a similar spatial pattern over the YRB, with an east–west-oriented gradient. A comparison of projected moisture transport into the YRB among the four scenarios reveals two channels (westerlies and monsoon flow) under SSP5-8.5, whereas the monsoon flow from adjacent oceans is important under the other three scenarios. Further analysis of the unique features of the projected moisture flux and substantial increase in summer precipitation under SSP5-8.5 indicates that the future summer precipitation trend over the YRB can be mainly attributed to an increase in evaporation and moisture advection.

Highlights

The Yellow River Basin (YRB) is located in the northern part of China, occupying the region between 33.5◦ N and 41.5◦ N and between 96◦ E and 119◦ E
A southeast–northwest precipitation gradient can be observed over the YRB, with a precipitation maximum in the southeast and a minimum in the northwest, which may be caused by the northward propagation of the East Asian summer monsoon (EASM) [36]
These results indicate that the characteristics and related physical mechanisms of future summer precipitation changes over the western and eastern parts of the YRB may show differences, which remain to be addressed in future work

Summary

Introduction

The Yellow River Basin (YRB) is located in the northern part of China, occupying the region between 33.5◦ N and 41.5◦ N and between 96◦ E and 119◦ E. This area feeds around 107 million people and accounts for 13% of the total cultivated land in China [1,2]. The YRB is located in a semi-arid–semi-humid region and is strongly influenced by the distinct stepwise northward movement of the East Asian summer monsoon (EASM) [3,4]. Gaining further insight into the summer precipitation over the YRB is imperative for better human wellbeing and regional socioeconomic development related to water resource management, agriculture, and ecosystem services

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Discussion

Conclusion