Impact of Initial Field and Long Wave Radiation on Climate Modeling

Ten realizations of CCM2 (T42L18) with only slight variations in the initial states have been carried out. The results reveal the response of CCM2 to the initial field, and it is evident that there is substantial variability in the runs, with deviations in many places on the globe and various spectral scales being in excess of 10%. Similar results are found for clouds and temperature. Comparing ten CCM2 algorithm runs with three runs using CCM2, MOR and NMC algorithms, it is evident that the climate simulations for the runs with different algorithms show much larger variability from one another than that for the initial field without changes of LWR algorithms. Comparing the modeling results using the CCM2, MOR and NMC algorithms in the CCM2 model, it can be seen immediately that CCM2 and MOR runs are closer to one another than to the NMC run. Nevertheless, the differences on all charts exceed 10% in many places on the globe, which are far above the impact of the initial field on climate modeling.