Figure 8.14: Annual mean
tropical cooling at the last glacial maximum: comparison between model results
and palaeo-data. (Centre panel) simulated surface air temperature changes over
land are displayed as a function of surface temperature changes over the oceans,
both averaged in the 30°S to 30°N latitudinal band, for all the PMIP simulations:
models with prescribed CLIMAP SSTs (circles) and coupled atmosphere-mixed layer
ocean models (squares) (from Pinot et al., 1999). Numbers refer to different models:
circles, 1: LMD4, 2-5: MRI2, ECHAM3, UGAMP, LMD5 (higher resolution), 6-7: CCSR/NIES1,
LMD5, 8: GEN2. Squares : 1: LMD4,2: UGAMP, 3: GEN2, 4: GFDL, 5: HADAM2, 6: MRI2,
7: CCM1, 8: CCC2 (names refer to Tables 8.1 and 8.5).
Results from two EMIC models including a dynamical ocean model have also been
displayed (diamonds): 1-UVIC (Weaver et al., 1998), 2-CLIMBER-2 (Petoukhov et
al., 2000).
The comparison with palaeo-data: (upper panel) over land is with estimates from
various pollen data for altitudes below 1,500m (the label �nb data�
refers to the number of data points in three different regions corresponding to
the temperature change estimate plotted in the abscissa) from (Farrera, et al.,
1999); (right panel) the distribution of SST changes estimated from alkenones
in the tropics from the Sea Surface Temperature Evolution Mapping Project based
on Alkenone Stratigraphy (TEMPUS) (Rosell-Melé, et al., 1998) (nb data:
same as upper panel, number of data points for each temperature change). Caution:
in this figure, model results are averaged over the whole tropical domain and
not over proxy-data locations, which may bias the comparison (e.g., Broccoli and
Marciniak, 1996). For example, for the pollen data, extreme values are obtained
for specific regions: weakest values over the Indonesia-Pacific region and coldest
values over South America.
