Fig. 6 Observed average monthly rainfall versus VCSN estimates (top left), observed average monthly rainfall versus nearest NIWA station estimates (top right), residuals of VCSN rainfall estimates versus predicted values (bottom left) and residuals of nearest NIWA rainfall station estimates versus predicted values (bottom right).
Numerical simulations of the model show that, for the KwaZulu-Natal province, malaria burden increases with increasing mean monthly temperature and rainfall in the ranges ([17 25]°C and [32 110] mm), respectively (and decreases with decreasing mean monthly temperature and rainfall values).
Figure 3 Monthly rainfall and NDVI values for the Ilmotiok group ranch over a five-year period (2007 to 2012).
The model was developed with a commercially available data set of long-term monthly temperature and rainfall values for the study area at a resolution of 200 m/pixel [38], together with the NDVI and a plant-productivity index, both freely available from the NOAA-AVHRR satellites series.
This model was based on an a priori assumption that inland flood/landslide frequency is proportional to the frequency with which monthly rainfall exceeds the highest value that might occur once every 10 years, under baseline (i.e., 1961 1990) climate conditions.
The six aggregated bioclimatic variables we selected for analysis are biologically relevant, representing annual trends and limiting environmental factors derived from monthly temperature (mean, minimum and maximum) and rainfall values.
Both surface water and groundwater showed significantly less variability in δ-values (Fig. 3) than in monthly rainfall of the area (Table 3).
Monthly rainfall data for the 2010 2050 time period is statistically downscaled to daily values using a Markov chain algorithm, with results used only from GCMs that yield rainfall patterns that are statistically consistent with historical rainfall patterns.
Monthly rainfall data from 2003 to 2007 was provided by the National Meteorological Service and are presented as mean monthly values for the whole period.
