Evaluation of Downscaled Climate Projections over Sri Lanka

Abstract

This study presents an assessment of the Conformal Cubic Atmospheric Model downscaled climate projections at 8 km spatial resolution which are forced by sea surface temperature and sea ice concentration of three global climate models centred on Sri Lanka. Model simulations were compared with observed daily gridded precipitation and temperature data for the period from 1981 to 2005 over Sri Lanka. Statistical measures such as pattern correlation, mean biases and root mean square errors are calculated using observed and simulated data. The results show that the temperature biases range between -1.4 and -2.4 °C and pattern correlations vary among the seasons between 0.92 and 0.96. The model underestimates the temperature over the selected domain. The pattern correlation of rainfall varies among the seasons and it is relatively low for the southwest monsoon season which is 0.67 with RMSE about 3.8 mm/day. Simulations show small bias values during the northeast season with a strong pattern correlation of 0.76 and RMSE of 1.7 mm/day.