After a night of mild grass frost (minus 3°C) this picture, taken at 16h48 and just before sunset, shows that despite a whole day of sunshine (but none directly onto this patch of land) the frost does not melt as there is no heat from the atmosphere beaming down to earth!
As per previous tests, the ground directly below the frost is above zero °C and the air was also above zero °C, yet the ice remains.
And whilst the ice formed, it dumped 80 calories per gram into the atmosphere ....so much for "radiative forcing", "back-radiation" and the "greenhouse effect".
Best regards,
Hans