The Vertical Location of Net Radiometers

I. The Effects of the Underlying Air Layer

Abstract

Theory indicated that for surfaces with temperatures significantly different from that of the ambient air, net radiation measurements become increasingly less representative of surface conditions with increasing height above the surface. This effect of the intervening air layer between the net radiometer and the surface was found experimentally to create a 7% discrepancy between the net radiation measured at 50 cm above a dry, bare soil and that measured at 215 cm for the daylight hours. On a 24-hour basis the discrepancy amounted to 11% of the total net radiation. In this situation, true net radiation is obtained only at the surface.