Abstract
There are two methods, the “ d irect” and the “indirect (or subtraction)”, in obtaining the hemispherical (downward or upward) longwave radiation flux in the daytime. Both of them have some defects. The defect of the direct method is that the method is not practicable in the field where weather conditions vary, whlile that of the indirect method is troubles coming from difference in the sensitivity of the total radiometer as between the shortwave and the longwave spectral region.
Here is presented a methed by whic h the troubles in the indirect method can be eliminated and consequently the hemispherical longwave radiation flux in the daytime can be adequately obtained. An example of downward longwave radiation flux obtained by the method is presented.
