Abstract Understanding the trend of temperature and rainfall is of prime importance for climate change related research. This research aims to identify the trends of temperature and rainfall for the last 50 years (1966–2015) for Bangladesh. To detect the trends, the non-parametric Mann–Kendall test in combination with a trend-free pre-whitening approach for correcting the time series to eliminate the influence of serial correlation has been used whereas the Sen's slope method is used for identification of the trend value. Maximum, minimum, and mean monthly temperatures have been analyzed to identify the monthly, seasonal and annual trend. Four seasons are distinct in Bangladesh, namely, pre-monsoon, monsoon, post-monsoon and winter. In case of rainfall, mean monthly rainfall, 1-day maximum rainfall and consecutive 3-day maximum rainfall are analyzed in a similar fashion. For maximum, minimum and mean monthly temperature, the majority of the stations show an increasing trend for all three indices. Monsoon season observes highest increasing trend of 0.015 °C/yr for mean monthly temperature whereas the winter season shows the negative trend of −0.002 °C/yr. On an annual basis, the trend is increasing with a value of 0.008 °C/yr or 0.4 °C in 50 years having significance level, p .10. The trend of mean rainfall for annual basis shows an increasing trend of 5.675 mm/yr. The trend in one day and consecutive three-day maximum rainfall depicts that the trend is increasing in few places whereas in other places the trend is decreasing with no significant change. The research concludes that the climate of Bangladesh is getting cooler and drier for winter, on the other hand, warmer and wetter for the rest of the year.

中文翻译：

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使用预白化方法观察孟加拉国的温度和降雨趋势

摘要 了解温度和降雨趋势对于气候变化相关研究至关重要。本研究旨在确定孟加拉国过去 50 年（1966-2015 年）的温度和降雨趋势。为了检测趋势，使用非参数 Mann-Kendall 检验结合无趋势预白化方法校正时间序列以消除序列相关的影响，而 Sen 斜率方法用于识别趋势值。分析了最高、最低和月平均温度，以确定月、季节和年度趋势。孟加拉国有四个不同的季节，即季风前、季风、季风后和冬季。在降雨的情况下，月平均降雨量，1 天最大降雨量和连续 3 天最大降雨量以类似方式进行分析。对于最高、最低和月平均温度，大多数站点的所有三个指数都显示出增加的趋势。季风季节观察到月平均温度的最高上升趋势为 0.015 °C/yr，而冬季则显示负趋势 -0.002 °C/yr。以年为基础，趋势以 0.008 °C/yr 或 0.4 °C 的值在 50 年内增加，具有显着性水平，p .10。年平均降雨量呈5.675毫米/年的增加趋势。一天和连续三天最大降雨量的趋势表明，少数地方呈上升趋势，而其他地方呈下降趋势，无明显变化。