FUTURE CHANGES IN EXTREME RAINFALL OVER THAILAND USING MULTI-BIAS CORRECTED GCM RAINFALL DATA

  • Winai Chaowiwa, Kanoksri Sarinnapakorn, Sutat Weesakul

Tóm tắt

Climate change is a controversial issue presented in the media. Obviously, global climate change affects local climate significantly, especially extreme rainfall frequently causes more flood and drought problem. The impact results in loss of life, resources and agriculture products interrupting the national economic progress. Even though many institutes have predicted the future climate under the Representative Concentration Pathway scenario using Global Circulation Model, the predicted climate results depend on the initial conditions and modelled assumptions. Several predicted climate results might confuse audiences because they provide high uncertainty of climate prediction. Coping with the uncertainty of climate prediction requires an understanding of the future extreme rainfall possibility, so the consistency of extreme rainfall analysis is used to investigate the extreme rainfall in the aspect of duration, frequency, and intensity in the national scale. This study aimed to analyse the consistency index of future extreme rainfall using multi-bias corrected GCM under the CMIP5 Project. Extreme rainfall indices were calculated using 20 bias-corrected GCM climate data sets under the Representative Concentration Pathway (RCP4.5 and RCP8.5). Furthermore consistency analysis and statistical hypothesis testing were used to explore the extreme rainfall possibility areas. The focused extreme rainfall indices comprised CWD, CDD, Rx1D, Rx3D, Rx5D, R10mm, R20mm, R95PT, SDII and PRCPTOT indices. The new approach of consistency analysis in this study used hypothesis test for comparing 2 means to enhance a greater reliability of extreme rainfall indices. The results revealed significant changes of extreme rainfall indices including mean CWD increased 28 to 41% in RCP4.5 and 26 to 37% in RCP8.5. Mean R20mm increased 5 to 53% in RCP4.5 and 3 to 61% in RCP8.5. Finally, mean Rx5D increased 38 to 54% in RCP4.5 and 26 to 53% in RCP8.5. The resulting consistency indices could be used to identify areas where extreme rainfall indices have changed.

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Phát hành ngày
2021-06-04