Principal component analysis of the climate variables.

<p><i>cld</i>: cloud cover; <i>pre</i>: precipitation; <i>sol</i>: extraterrestrial solar radiation; <i>tmp</i>, <i>tmn</i> and <i>tmx</i> are respectively the daily mean, minimal and maximal temperatures; <i>dtr</i>: temperature amplitude; <i>vap</i>: vapour pressure; <i>pet</i>: potential evapotranspiration; and <i>swc</i>: relative soil water content. (a) correlation circle of axis 1 and 2; (b) correlation circle of axis 1 and 3; (c) projection of the country classes on the pca axis, India (Indi), Uganda (Uga), Brazil (Bra), Mexico (Mex), Costa Rica (CR), Kenya (Ken), Ivory Coast (IC), DRC (DRC), Indonesia (Indo), Ethiopia (Eth), French Guiana (FG), Ghana (Gha), Ecuador (Ec), Venezuela (Ven), Malaysia (Ma), Thailand (Th); (d) projection of the continental classes on the pca axis; and (e) projection of the global ecological zones on the pca axis (i.e. Tropical rainforest, Tropical moist deciduous forest, Tropical dry forest, Tropical mountain system and Subtropical humid forest). Note that axis 1 and 2 explain 41.70% and 28.12% of the total variation respectively, (a). The third axis explained 11.30% of the variance and was linked negatively to <i>sol</i> and <i>pre</i>, (b).