Table 1. Incident radiation, fraction absorbed, and total absorbed radiation for each source.

The absorbed radiation was normalized to a PPF of 1000 µmoles per m² per s for each radiation source. This does not result in exactly equal PAR (in watts per m²) because of spectral differences among radiation sources. The total absorbed radiation for each source is shown in bold. Leaf temperature was held constant at 25°C. Net longwave exchange with lower leaves or surfaces was assumed to be zero.

	UV (350–400 nm)	PAR (400–700 nm)	NIR (700–2500 nm)	Source longwave	Sky longwave	Emitted longwave	Total
	Incident radiation (W/m 2)
HPS	0.58	203	128	131	452	-448	467
LED	0.15	195	10	44	452	-448	253
Sun, greenhouse	18	219	252	0	452	-448	494
Sun, clear sky	19	219	289	0	300	-448	379
	Fraction absorbed
HPS	0.939	0.870	0.263	0.97	0.97	0.97	0.71
LED	0.934	0.943	0.923	0.97	0.97	0.97	0.90
Sun, greenhouse	0.938	0.894	0.214	0.97	0.97	0.97	0.53
Sun, clear sky	0.937	0.894	0.207	0.97	0.97	0.97	0.33
	Total absorbed radiation (W/m 2)
HPS	0.54	177	34	127	439	-435	342
LED	0.14	184	9	43	439	-435	240
Sun, greenhouse	17	196	54	0	439	-435	271
Sun, clear sky	18	196	60	0	291	-435	130