Energy and Moisture Transport in the Earth Climate System: Mean State and the Perturbation Response

• Main Author: Singh, Hansi
• Other Authors: Bitz, Cecilia M
• Format: Thesis
• Language: English
• Published: 2015
• Subjects: Climate Dynamics; Atmospheric sciences; Climate change; Applied mathematics; Antarctic; Arctic; The Antarctic; Antarc*; Antarctica; Ice Sheet; Sea ice
• Online Access: http://hdl.handle.net/1773/35124

Thesis (Ph.D.)--University of Washington, 2015 Four studies are presented which investigate how energy and moisture transport define the mean state of the Earth Climate System and its response to perturbations. In the first study, we use a global climate model to study the effect of flattening the orography of the Antarctic Ice Sheet on climate. A general result is that the Antarctic continent and the atmosphere aloft warm, while there is modest cooling globally. The large local warming over Antarctica leads to increased outgoing longwave radiation, which drives anomalous southward energy transport towards the continent and cooling elsewhere. Atmosphere and ocean both anomalously transport energy southward in the Southern Hemisphere. Near Antarctica, poleward energy and momentum transport by baroclinic eddies strengthens. Anomalous southward cross-equatorial energy transport is associated with a northward shift of the inter-tropical convergence zone. In the ocean, anomalous southward energy transport arises from a slowdown of the upper cell of the oceanic meridional overturning circulation and a weakening of the horizontal ocean gyres, causing sea ice in the Northern Hemisphere to expand and the Arctic to cool. Comparison with a slab ocean simulation confirms the importance of ocean dynamics in determining the climate system response to Antarctic orography. We conclude this study by briefly discussing the relevance of these results to climates of the past and to future climate scenarios. The remaining studies consider atmospheric moisture transport. First, we develop a new mathematical framework for analyzing results from climate modeling studies that employ numerical water tracers (WTs). Data made available from WTs, which track the movement of water in the aerial hydrological cycle from evaporation to precipitation, are used to analyze the sources and transport of precipitable water in the climate system. The precipitation over a tagged region is subdivided into contributions from local evaporation and ...