Milankovitch forcing and meridional moisture flux in the atmosphere : insight from a zonally averaged ocean–atmosphere model
Mysak, Lawrence A.
MetadataShow full item record
KeywordForcing; Moisture; Fluxes; Ocean models; Coupled models; Southern Ocean; Pacific Ocean; Atlantic Ocean; Indian Ocean
A 1-Myr-long time-dependent solution of a zonally averaged ocean–atmosphere model subject to Milankovitch forcing is examined to gain insight into long-term changes in the planetary-scale meridional moisture flux in the atmosphere. The model components are a one-dimensional (latitudinal) atmospheric energy balance model with an active hydrological cycle and an ocean circulation model representing four basins (Atlantic, Indian, Pacific, and Southern Oceans). This study finds that the inclusion of an active hydrological cycle does not significantly modify the responses of annual-mean air and ocean temperatures to Milankovitch forcing found in previous integrations with a fixed hydrological cycle. Likewise, the meridional overturning circulation of the North Atlantic Ocean is not significantly affected by hydrological changes. Rather, it mainly responds to precessionally driven variations of ocean temperature in subsurface layers (between 70- and 500-m depth) of this basin. On the other hand, annual and zonal means of evaporation rate and meridional flux of moisture in the atmosphere respond notably to obliquity-driven changes in the meridional gradient of annual-mean insolation. Thus, when obliquity is decreased (increased), the meridional moisture flux in the atmosphere is intensified (weakened). This hydrological response is consistent with deuterium excess records from polar ice cores, which are characterized by dominant obliquity cycles.
Author Posting. © American Meteorological Society, 2010. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 23 (2010): 4841–4855, doi:10.1175/2010JCLI3273.1.
Showing items related by title, author, creator and subject.
Wind, sea ice, inertial oscillations and upper ocean mixing in Marguerite Bay, Western Antarctic Peninsula : observations and modeling Hyatt, Jason (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2006-09)Two years of moored oceanographic and automatic weather station data which span the winter ice seasons of 2001-2003 within Marguerite Bay on the western Antarctic Peninsula (wAP) shelf were collected as part of the Southern ...
Wang, Jinbo (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2008-09)Coupled ocean/atmosphere simulations exhibit systematicwarm biases over the SouthWest African (SWA) coastal region. Recent investigations indicate that coastal ocean dynamics may play an important role in determining the ...
Dail, Holly J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2012-09)This thesis focuses on ocean circulation and atmospheric forcing in the Atlantic Ocean at the Last Glacial Maximum (LGM, 18-21 thousand years before present). Relative to the pre-industrial climate, LGM atmospheric CO2 ...