Temperature difference between the reference disk and a selected clumpy disk (top) and lines with optical depth τ ~ 1 of our reference disk and the clumpy disk (bottom). The density distribution in the bottom image is taken from Eq. (1). The optical depth is calculated at the wavelength of maximum stellar emissivity in the way of the stellar radiation. (η = 0.3, k = 32, i = 0°, M_dust = 10^-6M_⊙, a_min = 0.005 μm and a_max = 0.25 μm.)