- Prediction of temperature (0C) and rainfall
Bangladesh using SRES A1B scenarios
Regional climate model PRECIS has been used to predict
various climatic parameters such as temperature and rainfall over
Bangladesh. The mean temperature and rainfall have been calculated from
the data collected by ground based stations of Bangladesh Meteorological
Department (BMD) during 1948-2007. The following maps show various
measurement stations in Bangladesh and PRECIS 50km grid with 0.44 degree resolution.
Click on any station to see
the mean values (1948-2007) and future predictions (1990-2090) of
temp. and rainfall
- Change of mean temperature and rainfall over
The mean daily temperature and
rainfall over Bangladesh have been predicted by PRECIS regional climate
modeling. Results of mean changes (deviation) from base climatic year
(2000) are presented in the following two graphs.
Change of mean daily temperature (0C) over
Change of mean rainfall (mm/day) over Bangladesh.
- About regional climate model - PRECIS
PRECIS (pronounced as in the French
précis - "PRAY-sea") is based on the Hadley Centre's regional climate
modelling system. A regional climate model (RCM) is a downscaling tool that
adds fine scale (high resolution) information to the large-scale projections
of a global general circulation model (GCM). GCMs are typically run with
horizontal scales of 300km; regional models can resolve features down to
50km or less. This makes for a more accurate representation of many surface
features, such as complex mountain topographies and coastlines. It also
allows small islands and peninsulae to be represented realistically, where
in a global model their size (relative to the model gridbox) would mean
their climate would be that of the surrounding ocean. RCMs are full climate
models, and as such are physically based. They represent most if not all of
the processes, interactions and feedbacks between climate system components
represented in GCMs. They produce a comprehensive set of output data over
the model domain. There are three types of technique for obtaining regional
climate change projections: statistical, dynamical and hybrid
(statistical-dynamical) techniques. RCMs fall into the dynamical category.
The following figure shows
schematization of PRECIS experiment over Bangladesh. The position of pointer
has longitude of 143.04 and -10.06 (rotated longitude 59.06 and rotated
latitude -24.15) . The grid resolution is 0.44 degree having a domain of 88
by 88 with longitude of TLC is 336 and latitude of TLC is 15.9. Coordinates
of rotated pole has longitude 270.27 and latitude 66.09.
Figure below shows domain of the simulation
(region) over Bangladesh.
a. Domain of simulation
consists of 88 rows and 88 columns for 50km grid. A rim of 8 pixels along the
boundary will be excluded from the analysis.
b. Zoom window over
Bangladesh for 50km grid. Land mass is shown by green pixels and ocean is shown
by blue pixels.
Special Report on Emissions Scenarios (SRES) A1B scenario
assumes a balanced mix of technologies and supply sources, with
technology improvements and resource assumptions such that no single
source of energy is overly dominant. The implications of these
alternative development paths for future GHG emissions are challenging:
the emissions vary from the carbon-intensive to decarbonization paths by
at least as much as the variation of all the other driving forces across
the other SRES scenarios.
Last Updated on June 10, 2009. Contact: Dr. A.K.M.
Saiful Islam, Associate Professor, IWFM, BUET, Dhaka-1000, Bangladesh.