Xiaoqing Wu, Department of Geological and Atmospheric Sciences, Iowa State University
Climate modeling allows researchers to discover the latest trends and concerns regarding climate change. Connections can be made between different variables and models, which can help enhance understanding of the models themselves and define relationships within the model. These low-resolution models are sensitive to cloud and convection parameters, which is the primary focus of this study. The Iowa State Global Climate Model (ISUGCM) is analyzed and compared with other observational and model datasets. The impact of these convection and cloud mechanisms on GCMs in general is of interest in this study. Several variables are explored, with significant differences identified for each variable. Observed longwave radiation flux was not found overall significantly different from the ISUGCM, while the other six variables were. Shortwave radiation is over-estimated at high values, and the overestimations of total cloud near the equator correlate with the underestimation of shortwave flux here. Convective precipitation rate is found to shift with the ITCZ from season to season, which agrees with general behavior of the ITCZ itself. Precipitable water and relative humidity overestimations justify the vigorous convection in the model. Surface temperature correlates well with past data in non-extreme latitudes, but could take issue with albedo in higher latitudes. These conclusions can provide a basis for additional understanding of the impact of changing convection and cloud parameters in a GCM model. Therefore, these results can be applied to additional future adjustments in the model.
Tracy, Christopher, "Convection and Cloud Mechanisms in GCMs" (2017). Meteorology Senior Theses. 36.