Rainfall Variability and Linear Trend Models on North-West Part of Bangladesh for the Last 40 Years

M Anisur Rahman

doi:10.11648/j.ajam.20160403.16

Abstract

Rainfall has been extensively considered as one of the initial point towards the apprehension of climate change courses. Bangladesh is recently experiencing climate change impact related to hazards like cyclone, rainfall, flood, draught etc. Climate variable like rainfall is the most important parameter which is linked with agricultural aspects too for this country. Most of the rain occurred during monsoon period in Bangladesh. This study investigates temporal variability of rainfall and liner trend models on the North-West part of Bangladesh over the period of 1975-2014 using data from the Bangladesh Meteorological Department. We computed and analyzed the linear trend models by using least square estimation. We estimated mean with standard deviation, cross-correlation and linear trends of annual and monsoon rainfall using MS Excel and SPSS v21. The variability of rainfall between the stations was measured by correlation test. The annual and monsoon rainfall has been found in decreasing trends in recent times. In some areas in the North-Western part of the country, the amount of annual and monsoon mean rainfall may be decreased abruptly comparing with average normal rainfall all over the country. The linear trend analysis of rainfall reveals a bit different trend for the last four decades. The observed data and linear trend line shows the decreasing trend of annual rainfall rate is 0.102 mm per year, whereas the decreasing trend of monsoon season rainfall rate is 0.080 mm per year. The time series statistical analysis of this study also provided the information about the correlation coefficients of rainfall among the selected five stations of the South-West region. The result of this study would hopefully help the planners and program managers to take necessary actions and to measure disaster management, agricultural production, drought mitigation, flood control etc.

Highlights

Climate change has created a new challenge to hamper development process throughout the world
It has been observed that the amount of mean annual rainfall for different stations is found to be between 100 mm and 192 mm with standard deviation (SD) of 11 mm to 72 mm; whereas, the mean monsoon rainfall amount for different stations ranges between 205 mm and 480 mm with SDs of 23 mm to 181 mm
This study dealt with rainfall variability and linear trend for five rain gauge stations of North-Western part in Bangladesh for the period 1975-2014

Summary

Introduction

Climate change has created a new challenge to hamper development process throughout the world. Countries with lack of natural resources, poor infrastructures and unstable institutions have little capacity to adapt and are highly vulnerable [3]. These factors are intrinsically linked with those promoting sustainable development that aims to improve living conditions and access to resources. Climate of the north-western region, like rest of Bangladesh is characterized by extremely warm temperatures, low humidity and triviality seasonal variations in rainfall. In this region the monsoon climate substantially controls the life style of the peoples, especially under the social and economical conditions of agriculture dependent countries like Bangladesh.

Data and Methods

Results and Discussion

Conclusion