# Table 7 Temperature-, extraterrestrial radiation-, and precipitation-based empirical models and their parameters

Equations Parameter Reference
Temperature-based models
$$H/H_0 = a[1-\hbox {exp}(-b(\Delta T^{\mathrm{c}}))]$$ abc Bristow and Campbell (1984)
$$H/H_0 = a \times \hbox {exp}(b\Delta T)$$ ab Proposed model
$$H/H_0 = a[1-\hbox {exp}(-b(\Delta T^{\mathrm{a}}))]$$ ab Proposed model
$$H/H_0 = a \times \hbox {exp}(b\Delta T) + c \times \hbox {exp}(d\Delta T)$$ abcd Proposed model
$$H/H_0 = a(\sqrt{\Delta T})$$ a Hargreaves and Samani (1982)
$$H/H_0 = a(\sqrt{\Delta T})+b$$ a, b Chen et al. (2004)
$$H/H_0 = a\Delta T^{\mathrm{b}}$$ ab Proposed model
$$H/H_0 = a\Delta T^{\mathrm{b}}+c$$ abc Proposed model
$$H/H_0 = a\Delta T^2 + b\Delta T + c$$ abc Proposed model
$$H/H_0 = a\Delta T^3 + b\Delta T^2 + c\Delta T + d$$ abcd Proposed model
$$H/H_0 = a[1-\hbox {exp}(-b(\Delta T^{\mathrm{c}})/H_0)]$$ abc Goodin et al.
$$H/H_0 = a(\sqrt{\Delta T})(1+bH_0+c(H_0)^2)$$ abc Proposed model
$$H/H_0 = a + b\Delta T + cH_0$$ abc Proposed model
$$H/H_0 = a(\Delta T^{\mathrm{b}})(1+cP+dP^2)$$ abcd DeJong and Stewart (1993)
$$H/H_0 = a + b\Delta T + cP$$ abc Proposed model
$$H/H_0 = a(\Delta T^{\mathrm{b}})+c(P^{\mathrm{d}})$$ abcd Proposed model