Search

This paper analyses the ability exhibited by seven coupled global climate models of the Climate Model Inter-comparison Project 3 used in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change to simulate current zonally averaged surface air temperature (ZASAT) meridional profiles. The expansion in second order of ZASAT profiles by means of Legendre polynomials was compared with the same expansion carried out over the ZASAT profiles provided by the ERA40 and National Centers for Environmental Prediction reanalysis from 1961 to 1998. According to the theoretical support provided by the one-dimensional energy balance models (1D-EBMs), the Legendre coefficients corresponding to the ZASAT profile can be qualitatively interpreted as the independent modes that represent the meridional energy flux from the equator to the poles. We find that three models, MIROC3.2-MR, MIROC3.2-HR and MPI-ECHAM5 may be considered as the models that best reproduce the meridional structure of current ZASAT, although the differences between the models are not really large. Consequently, the results shown in this paper support the accuracy of the models in representing the poleward meridional heat fluxes and global thermal inertia under the qualitative interpretation provided by the 1D-EBM approach. [ABSTRACT FROM AUTHOR]

This paper reports analysis of the ability of 24 coupled global climate models that were used in the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change to simulate the current monthly seasonal cycle of sea level pressure, surface air temperature and precipitation over the Iberian Peninsula in the last two decades of the twentieth century. The period investigated runs from 1979 to 1998. In order to assess the performance of the models, averaged seasonal cycles and probability density functions (PDFs) calculated from model simulations are compared with the corresponding seasonal cycles, whilst PDFs are also obtained using the data from the ERA40 reanalysis and the Global Precipitation Climatology Project. We found that simulated PDFs generally provided a better fit to actual PDFs than seasonal cycles do. This conclusion indicates that when evaluating model performance, the climate variability as measured by means of PDFs is not the only climatic element that should be tested. Regarding the comparison based on the seasonal cycle, results also show that the root mean square skill score is more useful than the r skill score. To rank the AR4 models, sea level pressure, surface air temperature and precipitation variables were selected and a group of five AR4 models were identified as the models which best reproduce current climate in the area: MIROC3.2-HIRES, MPI-ECHAM5, GFDL-CM2.1, BCCR-BCM2.0 and UKMO-HADGEM1. The rank obtained should not be understood in a hierarchical manner because there is a certain degree of internal variability in the model ensembles. Finally, it should be noted that these results are in good agreement with other classifications found in the scientific literature. [ABSTRACT FROM AUTHOR]