Many of the steppe areas in the tropical zones (particularly in central Africa) do seem to be an artifact; the script organizes the two temperature inputs in order of how hot to distinguish summer/winter (so that the input order or hemisphere don't matter as much), but flipping the default order for regions that have the same input temperature category makes most of those areas at least somewhat smaller except for in Eastern Brazil (even though that change to the script shouldn't really change anything). The reason for that in turn is probably the calculation for the aridity threshold, which makes me wonder what the canonical way to treat the tropical zones with low seasonal temperature variation is, since which threshold is used depends on whether the high(er)-precipitation season is considered summer or winter. For reference, changing just that order gives this result:
earthTest13.png
For the
Am climates, looking at pixels that had both input temperatures > 18 °C (so all the
A pixels), after ruling out
Af by checking whether both precipitation inputs are > 60mm, I then check whether the lower precipitation >= (100 - (P
ann / 25)), where I compute an estimate for P
ann via (6 * P
1) + (6 * P
2). P
1 and P
2 are the mean of the min and max values for the precipitation categories of the two inputs (e.g. if input 1 is of the 100-200mm category, P
1 = 150mm and so on). A possible issue in high-precipitation cases is what I set the highest precipitation category to; I kind of eyeballed it since all I had to go off of was the category being 200mm+ and so the estimate there is actually 250mm. It's possible that is raising P
ann too much and feeding
Am to
Aw/
As, but I don't know what to base the reference precipitation for that category on instead since it lacks a maximum.