Net radiation to various surfaces.
Equations for the estimation of net radiation flux, some involving only a single climatic element, were compared with Penman's (4-element) formula and with measured values for well-watered grass at 7 sites. Most of the new equations were found to be only slightly less accurate than the Penman formula. All equations tended to give a slight underestimate of the flux to grass surfaces, as though the albedo were less than 0.25. Formulae for net radiation on to bare soil all gave considerable overestimates of the flux. For 2 sites it was shown to be possible to estimate monthly mean net radiation from a knowledge of only the albedo, latitude and overland distance upwind.-R.B.