Figure 6.10.1 Frequency (%) of July to June seasons at various levels of potential evapotranspiration deficit, ranging from the wettest site at Ruakura, to progressively drier distributions at Masterton and Blenheim

Text description of figure

This figure shows the frequency (in %, vertical axis) of observed seasons against the potential evapotranspiration deficit, PED. Frequency ranges from 0 to 50%, and PED is given in bins from <51mm, 51-100, 101-200 to 601-700, and >700mm. The PED curves for three different sites are plotted: Ruakura, Masterton, and Blenheim.

The curve for Ruakura, the wettest site, peaks at nearly 50% of seasons for a PED of 101-200mm and then descends rapidly to near 0% occurrence at a deficit of 401-500mm. The curve for Masterton starts off with a lower frequency of small PED values than the curve associated with Ruakura, peaks at nearly 40% for a PED of 201-300mm, and then descends rapidly to near 0% occurrence of seasons with 601-700mm deficit. The curve for Blenheim, the driest site, starts off with 0% occurrence for a PED of 51-100mm or below, climbs steadily and peaks at 30% occurrence for a PED of 401-500mm, after which it only gradually descends and still has a frequency of about 12% for a PED of 700mm and over.