Abstract:Surface energy fluxes play a significant role in land-air interaction. To quantify the influence of resistance coefficients on surface energy fluxes in the Simple Biosphere Model (SiB2), the sensitivities of sensible heat flux (H) and latent heat flux (LE) to resistance coefficients are examined by using the one-factor-at-a-time method and fractional factorial analysis method. The results show that, i) H is more sensitive to C2 (called ground to canopy air-space resistance coefficient) while LE is more sensitive to C1 (named bulk canopy boundary-layer resistance coefficient);ii) H increases with increasing C1 and decreases with increasing C2, while LE always decreases with increasing C1 or increasing C2;and iii) the sensitivities of both H and LE decrease with increasing coefficients and their relative sensitivities increase with increasing coefficients. Furthermore, the reasonable explanation about the sensitivity of H and LE are given considering the distribution of land cover and vegetation in Nagqu.