Abstract Author: Bhaskar Jha and Arun Kumar
Abstract Title: Variability and Predictability of the seasonal mean atmospheric circulation during winter in three version of ECHAM model
Abstract: For three versions of the ECHAM atmospheric general circulation model (AGCM)-ECHAM3; ECHAM4.5; ECHAM5-the global 200-mb height response to the observed SST forcing is examined. The analysis also includes a comparison of atmospheric response between low and high resolution simulations for one version of the model. The main focus of analysis is to compare the wintertime (DJF) seasoanl variability, predictability, simulation skill for different generations of the ECHAM model.
The DJF signal-to-noise pattern is very similar in all the versions of the models except for its magnitude. The signal-to-noise in ECHAM4.5 model is weak (less than unity) at higher latitude in both the hemisphere, while other versions have stronger signal-to-noise ratio (close to unity). Overall, all versions of the models show very similar spatial skill except pver Tropical Pacific and Tropical Indian Ocean where ECHAM5, for both resolutions, has better skill than ECHAM3 and ECHAM4.5. The model overall signal of DJF 200-mb height is stronger at T42 resolution compared to T85 but spatial patterns are very similar.