Assessing the Performance of CMIP5 Global Climate Models for Simulating Future Precipitation Change in the Tibetan Plateau

Kun Jia,Yunfeng Ruan,Chao Zhang,Yanzhao Yang

doi:10.3390/w11091771

Abstract

In this study, the performance of 33 Coupled Model Intercomparison Project 5 (CMIP5) global climate models (GCMs) in simulating precipitation over the Tibetan Plateau (TP) was assessed using data from 1961 to 2005 by an improved score-based method, which adopts multiple criteria to achieve a comprehensive evaluation. The future precipitation change was also estimated based on the Delta method by selecting the submultiple model ensemble (SMME) in the near-term (2006–2050) and far future (2051–2095) periods under Representative Concentration Pathways (RCP) scenarios RCP4.5 and RCP8.5. The results showed that most GCMs can reasonably simulate the precipitation pattern of an annual cycle; however, all GCMs overestimated the precipitation over TP, especially in spring and summer. The GCMs generally provide good simulations of the temporal characteristics of precipitation, while they did not perform as well in reproducing its spatial distributions. Different assessment criteria lead to inconsistent results; however, the improved rank score method, which adopts multiple criteria, provided a robust assessment of GCMs performance. The future annual precipitation was projected to increase by ~6% in the near-term with respect to the period 1961–2005, whereas increases of 12.3% and 16.7% are expected in the far future under RCP4.5 and RCP8.5 scenarios, respectively. Similar spatial distributions of future precipitation changes can be seen in the near-term and far future periods under the two scenarios, and indicate that the most predominant increases occurred in the north of TP. The results of this study are expected to provide valuable information on climate change, and for water resources and agricultural management in TP.

Highlights

The Tibetan Plateau (TP), referred to as the “Third Pole” of the world [1], is the highest plateau in the world
It is apparent that most global climate models (GCMs) can reasonably simulate the annual cycle of precipitation, but they generally overestimate the amount of precipitation over TP
All GCMs exhibit the same single-peak precipitation pattern as in the observations, which show that precipitation is concentrated in June–July–August–September (JJAS)

Summary

Introduction

The Tibetan Plateau (TP), referred to as the “Third Pole” of the world [1], is the highest plateau in the world. It has an average elevation of more than 4000 m and features complex terrains [2]. TP is identified as a region that is sensitive and vulnerable to climate change. It is experiencing a warming trend [4,5,6], which has profound impacts on the hydrological cycle and the ecological system. It is imperative to understand how climate will change in TP in the future

Methods

Results

Discussion

Conclusion