Notes on the Effects of Stability Correction (Full Energy Mode)¶

Prepared by Greg O'Donnell

The VIC model in full energy balance was applied to the Ohio basin upstream of St Louis, on a timestep of 3hrs and a spatial resolution of 0.5dd, for the calendar year 1992. The meteorological forcings data consisted of daily Tmax and Tmin, precipitation and wind, which were dissagregated to the model timestep of 3hrs using the internal VIC routines. Two model simulations were run, one in which an atmospheric stability correction was implemented (based on a Richardson number approach), and one without. Evaporation totals for each grid cell aggregated from 3hr totals to daily and weekly values for the simulation period are shown in the Figure 1. The effect of the stability correction is small, although during the winter there is enhanced evaporation in the simulation without the correction, with the reverse true in summer (ie at low and high evaporation rates).

Figure 1: Scatter plots of 3 hourly (Left) and weekly (Right) simulated evaporation with the stability correction (stab) and without (nostab).