Bangladesh Meteorological Department, Dhaka, Bangladesh.
Department of Economics and Sociology, Patuakhali Science and Technology University, Patuakhali, Bangladesh.
PLoS One. 2024 May 22;19(5):e0300070. doi: 10.1371/journal.pone.0300070. eCollection 2024.
Heat waves significantly impact people's lives and livelihoods and are becoming very alarming and recognized as hot topics worldwide, including in Bangladesh. However, much less is understood regarding recent hotspots, the frequency of heat waves over time, and their underlying causes in Bangladesh. The objective of the study is to explore the current scenario and frequency of heat waves and their possible causes across Bangladesh. The Mann-Kendall and Sen's slope techniques were used to determine seasonal and annual temperature trend patterns of heat wave frequencies. Daily maximum temperature datasets collected from the Bangladesh Meteorological Department (BMD) during 1991-2021 are applied. The frequency of days with Tmax≥ 36°C as the threshold was used to compute different types of heat waves based on the BMD's operational definition. The results show that the mild heat wave (MHW) days followed the subsequent hotspot order: Rajshahi (103) > Chuadanga (79), Ishurdi (60), and Jessore (58), respectively. The frequency of days with Tmax≥36°C was persistence for many days in 2014, especially in the western part of Bangladesh compared to other parts. Similarly, the heat waves condition shown its deadliest event by increasing more days in 2021. The highest increasing trend was identified at the Patuakhali site, with a rate of 0.516 days/year, while the highest decreasing trend was noticed at the Chuadanga site, with a rate of -0.588 days/year. The frequency of days (Tmax≥36°C) is an increasing trend in the south-western part of Bangladesh. The synoptic condition in and around Bangladesh demonstrates that the entrance of heat waves in Bangladesh is due to the advection of higher temperatures from the south/southwest of the Bay of Bengal. The outcomes will guide the national appraisal of heatwave effects, shedding light on the primary causes of definite heatwave phenomena, which are crucial for developing practical adaptation tools.
热浪对人们的生活和生计有重大影响，已成为全球关注的热点话题，包括孟加拉国。然而，人们对孟加拉国近期的热点地区、热浪随时间的频率以及其潜在原因的了解甚少。本研究旨在探讨孟加拉国目前的热浪状况和频率及其可能的原因。本研究采用 Mann-Kendall 和 Sen 的斜率技术来确定季节和年际热浪频率的温度趋势模式。应用孟加拉国气象部门（BMD）在 1991-2021 年期间收集的日最高温度数据集。根据 BMD 的操作定义，使用 Tmax≥36°C 作为阈值的天数来计算不同类型的热浪。结果表明，轻度热浪（MHW）天数遵循随后的热点顺序：拉杰沙希（103）>乔德哈（79），伊舒尔迪（60）和杰索尔（58）。在 2014 年，Tmax≥36°C 的天数持续多日，尤其是在孟加拉国西部与其他地区相比。同样，热浪状况在 2021 年增加了更多的天数，显示出其最致命的事件。在巴图阿卡利站点，发现了最高的增加趋势，增长率为 0.516 天/年，而在乔德哈站点，发现了最高的减少趋势，减少率为-0.588 天/年。Tmax≥36°C 天数的频率在孟加拉国西南部呈上升趋势。孟加拉国及周边地区的天气状况表明，孟加拉国热浪的进入是由于孟加拉湾南部/西南部的热空气平流。研究结果将指导对热浪影响的国家评估，揭示确定热浪现象的主要原因，这对于开发实用的适应工具至关重要。
