Abstract:
This paper investigates the future climate of Sri Lanka using the variable-resolution Conformal Cubic Atmospheric Model
(CCAM) developed at CSIRO, Australia. Bias corrected sea surface temperatures (SSTs) and sea ice concentration from a
few global climate models (GCMs) such as CNRM-CM5, GFDL-CM3 and ACCESS1-0 from the CMIP5 simulations were used
as boundary conditions for simulations at 8 km horizontal resolution. Mean biases, root mean square errors (RMSE) and
pattern correlations have been calculated by comparing with observations to assess the performance of the model. The
results show that the temperature biases range between 00C and -30C. Pattern correlations vary among the seasons
between 0.96 and 0.92. The model tends to underestimate the observed values over the selected domain. The CCAM
simulations show small bias values during the northeast season with strong pattern correlations of 0.75 and RMSE values
of 1.7 mm/day. The pattern correlation of rainfall is relatively low for the southwest monsoon season with 0.68 and RMSE
about 3.9 mm/day. Projected changes in mean temperature and rainfall are presented for 2050. Area average
temperature is expected to increase by 10C under the high level emission scenario (RCP 8.5). The rainfall changes show
increase of about 40% in the northern part of the country during the first inter-monsoon season and about 20% in the
south eastern part of the country during the northeast monsoon season by 2050.
