ON THE BULK PARAMETERIZATION OF SURFACE FLUXES FOR VARIOUS CONDITIONSAND PARAMETER RANGES

A comparison between various parameterizations for the bulk transfer c oefficient for heat and momentum is carried out for a wide range of at mospheric stability and values of the roughness lengths for momentum a nd heat, z(0m) and 2(0h) respectively. It is confirmed that the parame terization of Launiainen compares well to a numerical iterative soluti on for the Obukhov length L as function of the gradients of wind speed and temperature over a limited range of z(0m)/z(0h) and stability con ditions. For z(0m)/z(0h) > 500, an alternative interpolation formulati on of Holtslag and Ek, in combination with the formulation of Launiain en, provides a better approximation.