Spatial sensitivity of heat storage to bottom boundary placement in climate models: Global variability
Abstract
Proper execution of n-dimensional climate models requires an appropriate bottom boundary condition placement (BBCP). In order for the subsurface to store a realistic quantity of heat, models must impose BBCPs that are sufficiently deep so as not to significantly perturb the quasi-steady state thermal profile. Previous work has shown that a BBCP of 10m can deprive the subsurface of 4.5 to 5.5 times the heat otherwise stored during a 110-year future climate scenario with a causally detached BBCP. In an effort to ascertain the spatial dependence of this phenomenon, temperatures from all continental grids (1552) of the state-of-the-art General Circulation Model (GCM) ECHO-g are each used to force an independent Land-Surface Model (LSM). Two distinct future ECHO-g climate scenarios are used as skin boundary conditions (A2 and B2) for the LSM, as well as two bottom boundary conditions: a zero-flux condition, and a globally interpolated geothermal flux data set. These 4 permutations of skin/bottom boundaries are used to examine subsurface heat storage discrepancies in climate models under an array of realistic conditions that includes ECHO-g soil moisture data, and freeze/thaw events at high latitudes. Results indicate the presence of a spatial dependence of heat storage on BBCP, and that this dependence may be used to quantify regional climatic effects. It is expected that these results will lead to further understanding of the role BBCP plays in producing plausible estimations of past or future climate at the global scale.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFM.U43A0855B
- Keywords:
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- 1600 GLOBAL CHANGE;
- 1622 Earth system modeling (1225);
- 1631 Land/atmosphere interactions (1218;
- 1843;
- 3322)