The downward flux by the atmosphere is the same as the real greenhouse effect. This flux is excatly the same as the sum of four energy fluxes: LW radiation absorption 155.6 + SW radiation absotpion 75.0 + Latent heating 90.8 + 24.2 = 345.6 W/m2
ClimatExam Scientific analyses of the climate change and global warming by Dr. Antero Ollila
The Earth's energy balance for clear, cloudy, and all-sky conditions is illustrated in Figure 1.
Dr. Ollila graph
This presentation is based on the publications and measurements carried out mainly during the sun cycle 23 (1995-2005). Therefore the solar constant is 1368 Wm^-2. During the present solar cycle this value is close to 1360 Wm^-2.
In this presentation are several new features:
1) The reflected flux Rp by the air,
2) The reflected flux Rc by the clouds,
3) Flux Sr absorbed by clouds - incoming flux is the reflected flux by surface
4) Incoming SW flux Sw absorbed by clouds
5) In coming SW flux Sb absorbed by clear air
6) Upward LW flux Ec emitted by clouds
7) Upward LW flux Eg emitted by cloudless atmosphere.
More details can be found in the two links below.