HR: 15:10h
AN: OS33D-07 INVITED     [Abstracts]
TI: Atmospheric Heat Transport Feedbacks to Freshwater Forcing in the Coupled GCM GISS Model
AU: * LeGrande, A N
EM: legrande@giss.nasa.gov
AF: NASA Goddard Institute for Space Studies and Center for Climate Systems Research, Columbia Univ., 2880 Broadway, New York, NY 10025 United States
AU: Schmidt, G A
EM: gschmidt@giss.nasa.gov
AF: NASA Goddard Institute for Space Studies and Center for Climate Systems Research, Columbia Univ., 2880 Broadway, New York, NY 10025 United States
AB: We perform a range of North Atlantic fresh water forcing simulations in the GISS ModelE coupled GCM. Here we present results from two sets of experiments designed to explore the sensitivity of the model to varying fresh water pulses: (1) 12 relatively small simulations emulate the magnitude and placement of 8kyr event and (2) much larger and longer P_hosMIP2 hosing experiments (0.1 Sv rate and 1 Sv rate). We find that within the first set of simulations, the modeled THC response to the freshwater forcing is stochastic - the largest volume of fresh water produces neither the largest response, nor the longest perturbation of THC. We evaluate the nature of modeled THC response given (1) a range of volumes, rates, and lengths of freshwater forcing; (2) two locations of fresh water input; and (3) two base states prior to the freshwater forcing. In all simulations, reduced overturning circulation in the Atlantic results in reduced northward heat transport by the ocean (OHT); we evaluate the response of heat transport in the atmosphere (AHT) and address to what extent the rest of the climate system compensates for the reduced OHT.
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4928 Global climate models (1626, 3337)
DE: 4962 Thermohaline
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005