Which indices are used to quantify the effect of climate on soil formation?

Following are the indices used to quantify the effect of climate on soil formation:
Thornwaite’s PE index developed a T/E index to represent thermal efficiency,
Precipitation- Climate affects the formation of soil indirectly, high temperatures and rainfall increase the degree of weathering and therefore the extent of soil development.
NSQ ( Niederschlag-sattigungsdefizit Quotient) is the humidity factor and is the total annual precipitation (mm) divided by the absolute saturation deficit of air.