Spatiotemporal evaluation of rainfall trend during 1979-2019 in seven climatic zones of Bangladesh

Abstract

ABSTRACT Rainfall trend analysis is common for climate change observation following the flood, drought, and other extreme hydrometeorological possibilities. Therefore, this study aims to evaluate the spatiotemporal rainfall trend for seven climatic zones in Bangladesh during 1979–2019. For the trend exploration Mann-Kendall (MK) trend test, slope estimator (Sens) and IDW techniques were utilised from the dataset of 27 stations. The findings shows descending annual trend of >-2.50, >1.95, >-1.80, >-1.60, >-1.31 and >-0.50 for the zones of (C)western region, (A)northern part of northern region, (B)north-western region, (E)south-central region, (D)south-western region and (G)north-eastern region, respectively, whereas ascending trend found for only (F)south-eastern region >1.83. Except for post-monsoon season zone F > 2.90 trends, all other seasonal trend is in a declining position. An increasing magnitude of rainfall is found >0.0355(F) for annual, >0.136(A), 0.0146(C), 0.0047(F) and 0.0093(G) for pre-monsoon, >0.0046(D), >0.0329(F) for post-monsoon, >0.0039(G) for winter and >0.0273(F) for monsoon seasons while all other zones are in decreased nature. Heterogeneously significant rainfall magnitude for annual, pre-monsoon, post-monsoon and monsoon seasons was also found, which includes >.03(F), >0.01(C), >0.03(F), >1.51(F), respectively. The findings recommend adopting operations and advanced design for water management with consideration of agricultural development and climate change.