Surface albedo plays a vital role in the evapotranspiration component of the wetland rice
water balance. This paper examines the influence of the phenological stages of rice (Oriza
sativa) field on observed albedo at a tropical site (Ghana) during the year 2002, with a view
to parametrizing a simple albedo model suitable for inclusion in models to estimate
evapotranspiration in wetland rice cropping systems. Crop management was similar for the
two planting dates used in this study. Measurements were taken from 10 m x 10 m plots
within rice fields. Four phenological stages were distinguished: emergence, vegetative,
flowering and physiological maturity. Surface albedo (α) was measured and simulated, using
a calibrated semi-empirical model, at solar zenith angles of 15°, 30°, 45°, 60°, and 75°. Leaf
area index (LAI) and crop height (h) were also monitored. Generally, albedo increases from
emergence to flowering for both planting dates but slightly decreases after flowering. The
correlation coefficient (r) between α and LAI equals 0.985 and the correlation coefficient
between α and h equals 0.908. The composed albedo model adequately predicted the
observed albedos with an overall r = 0.946 and mean bias error (MBE) of 0.002. The
extinction coefficient of the rice crop albedo was estimated as 0.75. Data presented are
valuable inputs in agricultural water management, rice production models, and especially as
vital sub-routine inputs in calculating evaporation and transpiration from wetland rice.