The Simulated Changes of Extreme Temperature Indices from Regional Climate Model Data
Supanee Maijandee *, Jiemjai Kreasuwun, Siramas Komonjinda, Wonchai Promnopas
Atmospheric Physics Research Unit, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
Possible changes in the frequency and intensity of extreme temperature indices in Thailand in the future (2020-2029) relative to the reference period (1990-1999) were investigated using daily temperature data simulated from the MM5 regional climate model (MM5-RCM). The bias-correction process was performed on the simulated temperatures in order to minimize the model biases prior to indices calculation. The evaluation reveals that the bias correction leads to improved temperature data. Extreme temperature indices were calculated based on the bias-corrected temperatures for both the reference and the future periods. The results show that significant increases in temperature extremes are found in all warm extreme indices including the maximum daytime and nighttime temperatures (TxX and TnX), and the frequency of hot days and nights (Tx90P and Tn90P) in all seasons throughout the country. The projections of Tx90P and Tn90P anticipate substantial increases in the frequency of hot days and nights. An increase of DTR is predicted in most stations over the northeast, central, and east during the warm season while in other seasons, DTR will likely be decreased. All indices projections in this research suggest that, in the future, the frequency and intensity of extreme temperature events will possibly increase significantly in most areas of Thailand. The change of the indices is most obvious during the cool season except for the Tn90P and DTR index, where the greatest changes are expected during the rainy season.
© 2013 Caspian Journal of Applied Sciences Research. All rights reserved.
Keywords: extreme temperature indices, projected climate change, MM5-RCM, bias-correction
Caspian Journal of Applied Sciences Research
2(10), pp. 77-87, 2013
Journal Homepage: www.cjasr.com
ISSN: 2251-9114
