Detection of Recent Changes in Climate Using Meteorological Data from South-eastern Bangladesh

Farzana Raihan Guangqi Li

doi:10.4172/2332-2594.1000127

Abstract

Analysis of meteorological records from four stations (Chittagong, Cox’s Bazar, Rangamati, Sitakunda) in south-eastern Bangladesh show coherent changes in climate over the past three decades. Mean maximum daily temperatures have increased between 1980 and 2013 by ca. 0.4 to 0.6°C per decade, with changes of comparable magnitude in individual seasons. The increase in mean maximum daily temperature is associated with decreased cloud cover and wind speed, particularly in the pre- and post-monsoon seasons. During these two seasons, the correlation between changes in maximum temperature and clouds is between -0.5 and -0.7; the correlation with wind speed is weaker although similar values are obtained in some seasons. Changes in mean daily minimum (and hence mean) temperature differ between the northern and southern part of the basin: northern stations show a decrease in mean daily minimum temperature during the post-monsoon season of between 0.2 and 0.5°C per decade while southern stations show an increase of ca. 0.1 to 0.4°C per decade during the pre-monsoon and monsoon seasons. In contrast to the significant changes in temperature, there is no trend in mean or total precipitation at any station. However, there is a significant increase in the number of rain days at the northern sites during the monsoon season, with an increase per decade of 3 days in Sitakunda and 7 days at Rangamati. These climate changes could have a significant impact on the hydrology of the Halda Basin, which supplies water to Chittagong and is the major pisciculture centre in Bangladesh.

Highlights

Global average temperature has increased by 0.85°C (0.6-1.05°C) during the post-industrial period (1880-2012) with an increase over the most recent decade (2003-2012) of ca. 0.78°C (0.72-0.85°C) [1,2] and it is extremely likely that more than half of the observed increased in the latter part of the 20th century is anthropogenic [3]
The lack of significance in the pre-monsoon season overall probably reflects the shortness of the length of record (22 years) for this station
The increase in maximum daily temperature is less marked in the monsoon season than in either the pre- or post-monsoon seasons, with values in the range of 0.4 to 0.6°C per decade compared to a range of 0.5 to 0.7°C per decade in the pre-monsoon and 0.5 to 1.1°C per decade in Station Cox's Bazar

Summary

Introduction

Global average temperature has increased by 0.85°C (0.6-1.05°C) during the post-industrial period (1880-2012) with an increase over the most recent decade (2003-2012) of ca. 0.78°C (0.72-0.85°C) [1,2] and it is extremely likely that more than half of the observed increased in the latter part of the 20th century is anthropogenic [3]. Precipitation, relative humidity, cloud cover and wind speed are available from four meteorological stations in south-eastern Bangladesh: Chittagong, Sitakunda, Rangamati and Cox’s Bazar (Figure 1 and Table 1).

Results

Conclusion