Projection of Precipitation and Temperature Extremes over Bangladesh
from CMIP6 SSP-RCP Scenarios
Abstract
Bangladesh is one of the most vulnerable countries of the world in the
event of climate change due to its unique geographical location. This
study assessed the impact of climate change on precipitation and
temperature extremes over Bangladesh from Coupled Model Intercomparison
Project Phase 6 (CMIP6) models under four SSP-RCP (Shared Socioeconomic
Pathway-Representative Concentration Pathway) scenarios (SSP126, SSP245,
SSP370, and SSP585). At first quantile mapping (QM) method was employed
to produce bias-corrected daily data. Then the future changes in climate
extremes were assessed using a subset of extreme temperature and
precipitation indices devised by the Expert Team on Climate Change
Detection and Indices (ETCCDI). For the assessment of precipitation
extremes, Consecutive Wet Days (CWD), Number of days with rainfall
greater than 10mm (R10mm), Wet Days Precipitation (R95p), total annual
rainfall (PRCPTOT), annual maximum 1-day precipitation (Rx1day), and
annual maximum 5-day precipitation (Rx5day) have been utilized while for
the temperature extremes, frequency of hot days (TX90p) and cool days
(TX10p) have been used. The results from the probability density
function (PDF) of most of the precipitation indices show rightward
shifting in the future indicating a tendency toward wetter conditions.
However, the magnitudes of change were different for the selected CMIP6
Global Climate Models (GCMs). The projected increase in CWD is greater
over the south-western region of the country while the projected
increase in PRCPTOT is greater over the north-eastern region of the
country under all scenarios. R10mm shows the highest increase for the
SSP585. In response to climate change, the TX90p shows a general
increase in this century. However, the frequency of cool days is
projected to decrease for most of the SSP scenarios. The results from
these analyses present an opportunity to understand the impact of
climate change on extreme events in Bangladesh and thus may help the
local decision-makers in policy-making, disaster management, and
infrastructure planning.