Radiative temperature in the heat balance of natural surfaces

摘要: A Linke-Feussner radiometer was used to measure the radiative temperature of natural surfaces, with small errors caused by divergence flux and its angular variation. On typical cloudless summer days, maximum tall crops open water close air temperature; a bare soil surface exceeded 20°C; short grass coldest at night. linear variation net (total) radiation short-wave established for several crops, increase in long-wave loss per unit (heating coefficient) 0·08. Daily totals as percentage solar income were: 37 cent (bare soil), 41 (short grass), 46 (tall crop), 53 (water). When aerodynamic character crop is known, effective resistance stomata water-vapour diffusion can be related theoretically difference between temperature. For rough vegetation, estimated stomatal 0·4 0·8 sec cm−1 heating coefficient almost independent wind speed about 0·1.