Radiative temperature in the heat balance of natural surfaces
Version of Record online: 14 DEC 2006
Copyright © 1962 Royal Meteorological Society
Quarterly Journal of the Royal Meteorological Society
Volume 88, Issue 378, pages 496–507, October 1962
How to Cite
Monteith, J. L. and Szeicz, G. (1962), Radiative temperature in the heat balance of natural surfaces. Q.J.R. Meteorol. Soc., 88: 496–507. doi: 10.1002/qj.49708837811
- Issue online: 14 DEC 2006
- Version of Record online: 14 DEC 2006
- Manuscript Revised: 13 JUL 1962
- Manuscript Received: 6 MAR 1962
A Linke-Feussner radiometer was used to measure the radiative temperature of natural surfaces, with small errors caused by the divergence of radiative flux and by its angular variation. On typical cloudless summer days, the maximum temperature of tall crops and of open water was close to maximum air temperature; a bare soil surface exceeded air temperature by 20°C; short grass was the coldest surface at night. A linear variation of net (total) radiation with net short-wave radiation was established for several tall crops, and the increase in long-wave loss per unit increase of net radiation (heating coefficient) was 0·08. Daily totals of net radiation as a percentage of solar radiation income were: 37 per cent (bare soil), 41 per cent (short grass), 46 per cent (tall crop), and 53 per cent (water).
When the aerodynamic character of a crop is known, the effective resistance of the stomata to water-vapour diffusion can be related theoretically to the difference between surface and air temperature. For rough vegetation, estimated stomatal resistance is 0·4 to 0·8 sec cm−1 and the estimated heating coefficient is almost independent of wind speed at about 0·1.