function ccm3_cloud_liquid_re_param_function, temp, p_ratio, land_flag

; Reference Kiehl et al., Journal of Climate, June 1998, pg 1133, eqn 5 & 6

; temperature is in K, p_ratio is the pressure/surface_pressure, land_flag=1 is land.
t=temp-273.

; over oceans the effective radius of liquid clouds is set to 10 microns

if t gt -10. and land_flag eq 1 then re=10.
if t le -10. and t ge -30. and land_flag eq 1 then re=10.-(5.*((t+10.)/20.))
if t gt -30. and land_flag ne 1 then re=10.
if t lt -30. then begin

pi_low=0.0 & pi_high=0.4 & rei_min=10. & rei_max=30.

re=rei_max-((rei_max-rei_min)*(((p_ratio)-pi_low)/(pi_high-pi_low)))
if re lt rei_min then re=rei_min
if re gt rei_max then re=rei_max

endif

return, re

end