Projection of the Precipitation Extremes in Thailand Under Climate Change Scenario RCP8.5

Teerachai Amnuaylojaroen

doi:10.3389/fenvs.2021.657810

Abstract

This study explores the predicted extreme precipitation during 2020–2029 in Thailand, using the output of the nested regional climate model (NRCM) with the Representative Concentration Pathway (RCP) 8.5 emission scenario. The research used five different extreme precipitation indices, i.e., annual precipitation total (PRCPTOT), the annual number of rainy days (RD), simple daily intensity index (SDII), consecutive dry days (CDDs), and consecutive wet days (CWD). The PRCTOT was generally located in eastern Thailand, with significant declining trends, while the increasing trend was found in northern Thailand. The quantity of the PRCPTOT varies marginally from 100 to 200 mm per decade. The annual RD was influenced mostly by the negative trends in Thailand. A remarkable trend is a rising of annual SDII, with major statistical increases ranging from 5 to 20%. A widespread decline in CWD was found in most regions. The statistically significant pattern of CWD has been geographically concentrated in the northern, southern, and eastern regions of Thailand. Southern Thailand continues to decline by −10 to −30%. A drastic decline has been observed in the south of Thailand. Projected interannual precipitation variability shows that December–January–February (DJF) variability will be greater than either annual or June–July–August (JJA) variability in most years, with the exception of 2022, 2025, and 2026, in which the JJA variability will be greater than both the annual variability and the DJF variability.

Highlights

Precipitation is an important factor in the hydrological cycle
In Southeast Asia, the future of the precipitation extremes was pedicted using the output from CORDEX-SEA simulation with 25-km grid spacing under emission scenarios of RCP4.5 and 8.5 at the end of the twenty-first century
We used the output from the simulation of the nested regional climate model (NRCM) with 10-km grid spacing under climate change scenario RCP8.5 for input data in the precipitation extreme indices, including annual precipitation total (PRCPTOT), the annual number of rainy days (RD), simple daily intensity index (SDII), consecutive dry days (CWD), and CDD, for studying the precipitation extremes in Thailand during the period 2020–2029

Summary

INTRODUCTION

Precipitation is an important factor in the hydrological cycle. It is one of the most important variables affecting life and human well-being because precipitation change can cause consequences to both the environment and the human society (Pielke and Downton, 2000; Trenberth et al, 2003; Barretta and Santos, 2014; Guan et al, 2014). In Southeast Asia, the future of the precipitation extremes was pedicted using the output from CORDEX-SEA simulation with 25-km grid spacing under emission scenarios of RCP4.5 and 8.5 at the end of the twenty-first century. Their results indicate that changes in extreme indices are more pronounced and cover a wider area under RCP8.5 than RCP4.5, with the most significant change in consecutive dry days (CDD) (Tangang et al, 2020). We used the output from the simulation of the nested regional climate model (NRCM) with 10-km grid spacing under climate change scenario RCP8.5 for input data in the precipitation extreme indices, including annual precipitation total (PRCPTOT), the annual number of rainy days (RD), simple daily intensity index (SDII), consecutive dry days (CWD), and CDD, for studying the precipitation extremes in Thailand during the period 2020–2029

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT