Trends in extreme rainfall and temperature indices in the western Thailand

Abstract

Trends in extreme daily temperature and rainfall have been analysed from 1961 to 2002 for the western Thailand (Mae Ping and Mae Klong river basins). Daily precipitation, maximum and minimum temperature data for 15 stations were analysed to calculate 21 extreme indices. The magnitude of trends was estimated using the linear regression method while its statistical significance was evaluated using the p-value at 5% significance level and Kendall-tau test. The result of the analysis depicts significant increase in the annual number of warm days and warm nights, with corresponding significant decreases in the annual number of cool days and cold nights. The warm spell duration indicator presents statistical rising trends. The trends for temperature indices are more consistent in the region compared to precipitation indices. There is insignificant decrease in annual total precipitation for nearly all stations. The maximum number of consecutive dry days (rain less than 1 mm) is increasing. The number of days with rainfall more than 10 and 20 mm has declined over both basins except at Kanchanaburi station. Analysis also reveals that there is less spatial coherent in other extreme indicators, namely, maximum 1-day and 5-days rainfall amount and simple daily intensity index.

Changes in Climate Extremes over North Thailand, 1960–2099

“…Warm days and warm nights (TX90p and TN90p) also increased with very high significant trend whereas cool days (TX10p) and cool nights (TN10p) decreased [13,49] with the same trend along with mild to steep slope. Similar results were found by another study of Sharma and Babel [50] for Western Thailand. In the observed period, significant increases in warm extremes (TX90p, TN90p, SU35, TR25, and WSDI) were experienced in North Thailand where reverse trend was observed in case of cold extremes (TX10p, TN10p, and CSDI) which is also favored by the negative trend of diurnal temperature range (DTR) except in Lamphun Province (Figure 2).…”

“…All rainfall extremes showed insignificant trend except consecutive dry days (CDD) which was increasing with significant trend during the observed period of 1960-2010 (Table 3) in Chiang Rai and Tak provinces. Similar results were observed in another study of Sharma and Babel [50]. Except Lamphun Province, negative trends of PRCPTOT and R10 indicate that the rainfall was decreasing (Figure 2) over the study area.…”

“…The sign of the trend for the annual total rainfall is compared with the sign of the trends in the R99p index. At a station where the annual amount decreases, negative R99p trends are indicative of a large contribution of the extremes and vice versa [50].…”

Trends in Extreme Climate Indices for Pará State, Brazil

“…Thus, an initial step for studies involving the climate change impact is the analysis of extreme indices (Sharma and Babel, 2014). Many studies, such as Aguilar et al (2005), Vincent et al (2005), Alexander et al (2006), Haylock et al (2006), Marengo et al (2009), Marengo et al (2010) have revealed that significant changes in some climate variables have taken place in the South America over the last century.…”

CLIMATE CHANGE IN THE TRIÂNGULO MINEIRO REGION – BRAZILl

“…Research on this theme has demonstrated that greenhouse gas emissions (GARREAUD et al, 2009;KELLER, 2009;RUZMAIKIN et al, 2015) and other aspects of climate change are reaching the IPCC projections upper limits (EASTERLING et al, 1997;VINCENT et al, 2005;ALEXANDER et al, 2006;SILLMANN & ROECKNER, 2008;ORLOWSKY & SENEVIRATNE, 2012;CHOI et al, 2014;SHARMAA & BABELB, 2014;BARBU et al, 2015;GUAN et al, 2015;HU et al, 2015;PARAK et al, 2015;ALEXANDER, 2016 andRAO et al, 2016). In addition, the climate change key indicators are showing values beyond the natural variability in the Earth system, i.e.…”