Net primary production of natural vegetation [Uchijima & Seino, 1987]

Net primary production = gross primary production - respiration of plants
Values are obtained by empirical formula between ecological field survey &
Net radiation Rnet
Radiative index of dryness = Rnet / (L×P) [Budyko, "Climate and Life"]
P=precipitation; L=latent heat of vaporization per unit mass.
[The figure shown here were taken from
Uchijima Z. and Seino H., 1987:
Distribution maps of net primary productivity of natural vegetation
and related climatic elements on continents.
National Institute of Agricultural Environmental Science, Japan.]