@article {307,
	title = {The impact of sea ice concentration accuracies on climate model simulations with the GISS GCM},
	journal = {Journal of Climate},
	volume = {14},
	year = {2001},
	note = {id: 1944; PT: J; UT: WOS:000169239100008},
	pages = {2606-2623},
	abstract = {The Goddard Institute for Space Studies global climate model (GISS GCM) is used to examine the sensitivity of the simulated climate to sea ice concentration specifications in the type of simulation done in the Atmospheric Model Intercomparison Project (AMIP), with specified oceanic boundary conditions. Results show that sea ice concentration uncertainties of +/-7\% can affect simulated regional temperatures by more than 6 degreesC, and biases in sea ice concentrations of +7\% and -7\% alter simulated annually averaged global surface air temperatures by -0.10 degrees and +0.17 degreesC, respectively, over those in the control simulation. The resulting 0.27 degreesC difference in simulated annual global surface air temperatures is reduced by a third, to 0.18 degreesC, when considering instead biases of +4\% and -4\%. More broadly, least squares fits through the temperature results of 17 simulations with ice concentration input changes ranging from increases of 50\% versus the control simulation to decreases of 50\% yield a yearly average global impact of 0.0107 degreesC warming for every 1\% ice concentration decrease, that is, 1.07 degreesC warming for the full +50\% to -50\% range. Regionally and on a monthly average basis, the differences can be far greater, especially in the polar regions, where wintertime contrasts between the +50\% and -50\% cases can exceed 30 degreesC. However, few statistically significant effects are found outside the polar latitudes, and temperature effects over the nonpolar oceans tend to be under 1 degreesC, due in part to the specification of an unvarying annual cycle of sea surface temperatures. The +/-7\% and +/-4\% results provide bounds on the impact (on GISS GCM simulations making use of satellite data) of satellite-derived ice concentration inaccuracies, +/-7\% being the current estimated average accuracy of satellite retrievals and +/-4\% being the anticipated improved average accuracy for upcoming satellite instruments. Results show that the impact on simulated temperatures of imposed ice concentration changes is least in summer, encouragingly the same season in which the satellite accuracies are thought to be worst. Hence, the impact of satellite inaccuracies is probably less than the use of an annually averaged satellite inaccuracy would suggest.},
	issn = {0894-8755},
	doi = {10.1175/1520-0442(2001)014<2606:TIOSIC>2.0.CO;2},
	author = {Parkinson, C. L. and Rind, D. and Healy, R. J. and Martinson, D. G.}
}
@article {375,
	title = {The origin of Antarctic precipitation: a modelling approach},
	journal = {Tellus Series B-Chemical and Physical Meteorology},
	volume = {52},
	year = {2000},
	note = {id: 1942; PT: J; UT: WOS:000085432600002},
	pages = {19-36},
	abstract = {The contribution of different moisture sources to Antarctic precipitation for present-day and glacial conditions is estimated with the NASA/GISS Atmospheric General Circulation Model. Despite its low horizontal resolution (8 degrees x 10 degrees), this model simulates reasonably well the broad features of the observed present-day hydrological cycle. Simulated present-day Antarctic precipitation is dominated throughout the year by moisture from a subtropical/midlatitude band (30 degrees S-60 degrees S). The moisture supplied to a given coastal area of Antarctica originates mostly in the adjacent oceanic basin; closer to the pole, other oceanic basins can also contribute significantly. Replacing the present-day sea surface temperatures (SSTs) and sea ice cover in the GCM with those from the CLIMAP oceanic reconstruction for the last glacial maximum (LGM), greatly increases the simulated latitudinal temperature gradient, with the consequence of slightly enhancing the contribution of low latitude moisture to Antarctic precipitation. It also changes the seasonality of the different contributions and thus their budget, particularly in coastal regions. Because the nature of LGM tropical SSTs is still under debate, Ne performed an additional LGM simulation in which the tropical SSTs are reduced relative to those of CLIMAP. The resulting decrease in the latitudinal gradient brings the relative contributions to Antarctic precipitation more in line with those of the present-day simulation.},
	issn = {0280-6509},
	doi = {10.1034/j.1600-0889.2000.00951.x},
	author = {Delaygue, G. and Masson, V. and Jouzel, J. and Koster, R. D. and Healy, R. J.}
}
@article {395,
	title = {The role of oceanic forcing in mid-Holocene Northern Hemisphere climatic change},
	journal = {Paleoceanography},
	volume = {14},
	year = {1999},
	note = {id: 1943; PT: J; UT: WOS:000079325100009},
	pages = {200-210},
	abstract = {Previous model investigations suggested that changes in orbital forcing and feedbacks associated with northward expansion of the boreal forest were both required to explain the full magnitude of enhanced high-latitude Northern Hemisphere summer warming at 6 ka, thus implying that biospheric feedbacks (decreased planetary albedo associated with forest expansion) may be large in the future [Foley ct at., 1994; TEMPO (Testing Earth System Models with Paleo-Observations), 1996]. Before the magnitude of past biospheric and other feedbacks can be estimated with confidence, however, the role of realistic high-latitude oceanic forcing (i.e., sea surface temperature (SST) increases and sea ice reductions) should also be considered. Here we review existing paleoceanographic observations that suggest portions of the North Atlantic were up to 4 degrees C warmer than today at 6 ka. We then combine our estimates of mid-Holocene North Atlantic SST and sea ice conditions with new climate model simulations to suggest that a significant portion of high-latitude summer warming at 6 ka in the Northern Hemisphere can be accounted for by altered orbital forcing, SSTs, and sea ice relative to today. Our results underscore the importance of incorporating realistic boundary conditions when using paleoenvironmental data to evaluate the climate system{\textquoteright}s sensitivity to altered forcing and suggest that high-latitude oceanic feedbacks were major contributors to enhanced high-latitude summer warming in the Northern Hemisphere at 6 ka.},
	issn = {0883-8305},
	doi = {10.1029/1998PA900011},
	author = {Kerwin, M. W. and Overpeck, J. T. and Webb, R. S. and DeVernal, A. and Rind, D. H. and Healy, R. J.}
}
