Browsing by Author "Kanokrat Buareal"

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    A 177 years extended of teak chronology revealing to the climate variability in phrae province, northern of thailand
    (2020-01-01) Kanokrat Buareal; Supaporn Buajan; Sineenart Preechamart; Chotika Muangsong; Nathsuda Pumijumnong; Faculty of Environment and Resource Studies, Mahidol University; Mahidol University
    © 2020, Chulalongkorn University - Environmental Research Institute. All rights reserved. Teak ring-width is one of the promising paleoclimate proxies in the tropical region. Tree-ring chronology spanning from 1840 to 2016 (177 years) was derived from 76 trees from Phrae Province, northern Thailand. A total of 141 core samples were cross-dated, a standardized master was constructed, and the tree residual master chronology was developed by ARSTAN program. The tree-ring chronology has a significant positive correlation with the monthly rainfall and relative humidity during the monsoon season (May–June). In addition, the growth of tree-ring width also significantly inversely correlated with Niño 3, Niño 3.4, and Niño 4 indices during the second half of the dry season (January–March). We reconstructed summer monsoon season (May–June) rainfall based on a linear regression model which explained 21.95% of the actual rainfall variance. The trend of the reconstructed rainfall record shows a decrease of 0.6 mm per decade and substantially showed four wet periods and five dry periods. These results suggest that this teak chronology has a good potential to be a high-resolution proxy for reconstructing the past local climate in northern Thailand.
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    Climate variability beyond 100 years in Northern Thailand derived by teak ring-width
    (Mahidol University. Mahidol University Library and Knowledge Center, 2024) Kanokrat Buareal; Nathsuda Pumijumnong; Paramita Punwong
    Teak ring-width has been proven to be the proxy of paleoclimate study in the tropical region. Seventy-six trees from Phrae province Northern Thailand were cross-dated to create a standardized master. The teak residual master chronology spanning from 1840 to 2016 (177 years) was calculated by the ARSTAN program. Dendroclim 2002 was used to assess the correlation between the teak tree-ring indices and climate data; monthly total rainfall, monthly average relative humidity and temperature, and Nino indices. The results revealed that the monthly rainfall and relative humidity during the monsoon season (May to June) showed a significant positive relationship with the teak-ring width index. On the other hand, there was a significant negative correlation between the temperature and the teak tree-ring index during the same period. In addition, the growth of tree-ring width also significantly inversely correlated with Nino 3, Nino 3.4, and Nino 4 indices during the second-half of dry season (January to April). The amount of May to June rainfall was used for reconstruction backward to 1840. The trend of the 177 years reconstructed rainfall decreased 0.6 mm per decade and substantially showed four wet periods and five dry periods. The dry period during 1917 to 1922 in our reconstruction coincided with the historical record of severe drought resulting in the loss of agricultural products in 1920. These results suggest that this teak index has a good potential to be a high-resolution proxy for reconstructing the past local climate in northern Thailand.