Bioclimatic indices for use in studies of ecosystem
function, species distribution, and vegetation dynamics under
changing climate scenarios depend on estimates of surface
fluxes and other quantities, such as radiation, evapotranspi-
ration and soil moisture, for which direct observations are
sparse. These quantities can be derived indirectly from me-
teorological variables, such as near-surface air temperature,
precipitation and cloudiness. Here we present a consolidated
set of simple process-led algorithms for simulating habitats
(SPLASH) allowing robust approximations of key quantities
at ecologically relevant timescales. We specify equations,
derivations, simplifications, and assumptions for the estima-
tion of daily and monthly quantities of top-of-the-atmosphere
solar radiation, net surface radiation, photosynthetic photon
flux density, evapotranspiration (potential, equilibrium, and
actual), condensation, soil moisture, and runoff, based on
analysis of their relationship to fundamental climatic drivers.
The climatic drivers include a minimum of three meteoro-
logical inputs: precipitation, air temperature, and fraction of
bright sunshine hours. Indices, such as the moisture index,
the climatic water deficit, and the Priestley–Taylor coeffi-
cient, are also defined. The SPLASH code is transcribed in
C++, FORTRAN, Python, and R. A total of 1 year of results
are presented at the local and global scales to exemplify the
spatiotemporal patterns of daily and monthly model outputs
along with comparisons to other model results.