Plot obtained from correspondence analysis
Plot of a physiognomic analysis from Forest et al. (1999). The dots represent leaf collection sites, plotted against the axes for temperature (the vertical axis, ranges from hot to cold) and water stress (horizontal axis, ranges from wet to dry). The vectors represent the correlation of atmospheric parameters temperature (T), enthalpy (H), specific humidity (q), and relative humidity (RH). The enthalpy (H) axis plots equally on the temperature and water stress axes, indicating that a paleoclimate inference of enthalpy will provide information about both temperature and water stress.
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MAT and MART used to make elevation inferences
Mean annual temperature (MAT) is plotted on the vertical axis, against mean annual range of temperature (MART) on the horizontal axis. The lines radiating from the left side of the plot separate various ranges of different modern plants, such as conifer forest and broad-leaf evergreen forest. The descending dotted lines are percentage of days per year with subfreezing temperatures. Fossil flora are plotted in the circles with estimated elevations. Florissant, the bottommost circle, is estimated at 455 m. From Axelrod (1998).
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Movement of moist static energy in the atmosphere
Moist static energy is conserved in an air parcel as it moves over a mountainous region because the energy within the parcel is converted between sensible heat, latent heat, and potential energy (Forest et al., 1995). The potential energy of the high site is the difference in moist enthalpy, as shown by the equations for h in the figure, allowing for a calculation of altitude Z.
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Zonal distribution of mean annual moist static energy
Mean annual moist static energy (kJ/kg) was calculated from mean temperature and mean specific humidity. Dots indicate meteorological stations used in the dataset. The inset box plots mean annual moist static energy as a function of latitude, with latitude on the horizontal axis and h on the vertical axis (Forest et al., 1999). Mean annual moist static energy is mostly invariant with longitude, although some perturbations to the zonal distribution can be seen.
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