Understanding the significant disparity between observations and CMIP5 model simulations at the ocean/atmosphere interface in the tropics
Date of Award
Doctor of Philosophy (PhD)
John R Christy
Richard T McNider
Roy W Spencer
Arastoo Pour Biazar
Tropics--Climatic factors--Mathematical models., Climatic changes--Mathematical models., Ocean-atmosphere interaction.
Observations indicate that the warming of the tropical atmosphere is proceeding at a rate significantly less than depicted in model projections. Surface energy fluxes play a central role in the coupling of the atmosphere and ocean components which impact tropospheric temperature. In order to investigate the atmospheric temperature disparity, this study examines the near-surface air temperature and surface energy fluxes at the ocean-atmosphere interface using a suite of Coupled Model Intercomparison Project 5 (CMIP5) models, comparing their output with observations. Observations are used to test model fidelity with respect to the surface energy fluxes (net shortwave, net longwave, latent heat flux, and sensible heat flux), spatially and temporally. Results show that the Multi-Model Ensemble (MME) means of each component are similar to observations in the area-weighted averaged climatological mean state, except for largely overestimated latent heat flux. Furthermore, there is a long-term upward trend in the observations but not in the CMIP5 models. The spatial distribution and magnitudes thereof, in contrast, are significantly different in the majority of the components. Additionally, there is considerable range across individual CMIP5 models indicating heavy dependence on parameterizations.
Junod, Robert Anthony, "Understanding the significant disparity between observations and CMIP5 model simulations at the ocean/atmosphere interface in the tropics" (2019). Dissertations. 167.