Cilia, D. M. (2010). B.Sc. (Hons) Dissertation. Validation of the PRECIS regional climate model: Rainfall and Temperature over the Mediterranean Region.

Supervisor: Dr N. Aquilina
Co-supervisor: Prof. C. V. Sammut

Abstract

The nesting of Regional Climate Models (RCMs) within Global Climate Models (GCMs) has become a fundamental tool in order to achieve a fine spatial resolution for climate projections. Using the PRECIS (Providing REgional Climates for Impact Studies) RCM, a simulation for a hind cast, thirty year experiment for the period 1960 to 1990 was run to compare and evaluate the model's validation over the Mediterranean region on 50 km grid spacing. Initial and lateral boundary conditions from the ECMWF reanalysis data sets, GCM driving forcing and surface fields from the Climate Research Unit at the University of East Anglia were obtained for the RCM model. Time series and spatial plots were compared with measured surface seasonal and annual data sets from monitoring stations and data centres for the near-surface air temperature and precipitation parameters. Statistical tests were used in order to describe sufficiently the modelled parameters distribution. According to the results, the PRECIS model generally overestimates the temperature and also the precipitation parameter.

A further model assessment was done by comparing measured and modelled data from the year 1981 with three model experiment simulations for the same region for the year 2081 using the SRES future scenarios based on technological, demographic and economic growth. This was performed to justify the evaluation and validation of the model uncertainties. From these results, estimations and suggestions on the expected significance of the temperature and precipitation in the future, together with a comparison between the hind cast simulation and another simulation for the period 2071 to 2100 over the Mediterranean region, are presented and discussed.