None of the work presented below is mine, full credit goes to Kugelblitz for this one.
After reviewing the original Millenium Emperor Nova calculation, I thought that it could be improved upon. For this calculation, I'm using the pixel scaling done in Ugarik's calc, and consequently some of the working is going to be the same (namely the cloud mass/volume calculation). The changes regard the clouds displacing as soon as the beam passes them, and distance from the underground to the surface to the top of the Nimbostratus cloud, which was not factored in the calculation.
Pixel Scaling (By Ugarik)
Distance[]
To find the speed, we need to find the distance that the beam traveled within the given timeframe (1.98 seconds). The beam first traveled from the bottom of the monster association base, which we know from the webcomic is at least 1500m below the surface. Next, we need to find the distance between the surface and the top of the Nimbostratus cloud seen in the panel. Using the average heights for the Cirrus and Nimbostratus cloud, and assuming that the Cumulus is a Congestus (since a regular Cumulus would not be at the same height as the Cirrus clouds) we can deduce that it's likely that the Nimbostratus cloud is 2000m thick (minimum thickness) and a base 3000m high. Then finally for the panel itself, Ugarik measured the length of the beam to be 23144.4m with pixel scaling.
This gives us a total distance traveled of 1500 + 23144.4 + 2000 + 3000 = 29644.4m
Nova Velocity[]
29644.4/1.98 = 14971.91919m/s
Cumulus Energy[]
Cumulus has a thickness of 600m, and using Ugarik's pixel calculations
Radius 1 - 109.8 px - 2007.3 m
Radius 2 - 300.2 px - 5488.1 m
Mass of Cumulus:
0.5*[(600*pi*5488.1^2)-(600*pi*2007.3^2)] = 24589234691.5 m^3
Mass = 24589234691.5*1.003 = 24663002395.6 kg
Timeframe:
600/14971.91919 = 0.04007502261s
Velocity & Energy:
2007.3/0.04007502261 = 50088.55565m/s
KE = 0.5*24663002395.6*50088.55565^2 = 3.093805211e+19 J = 7.41 Gigatons (Island level)
Cirrus Energy[]
Cirrus' thickness is 100 m
Radius 1 of Cirrus 1 - 131 px - 2394.9 m
Radius 1 of Cirrus 2 - 89.6 px - 1638 m
Radius 2 Cirrus 1 - 143.6 px - 2625.2 m
Radius 2 Cirrus 2 -116.52 px - 2130.2 m
Mass of Cirrus 1:
0.5*[(100*pi*2625.2^2)-(100*pi*2395.9^2)] = 180851786.2 m^3
Mass = 180851786.2*1.003 = 181394341.6 kg
Mass of Cirrus 2:
0.5*[(100*pi*2130.2^2)-(100*pi*1638^2)] = 291336857.7 m^3
Mass = 291336857.7*1.003 = 292210868.3 kg
Timeframe:
100/14971.91919 = 0.006679170434s
Velocity & Energy:
2394.9/0.006679170434 = 358562.4927m/s
KE of Cirrus 1 = 0.5*181394341.6*358562.4927^2 = 1.166e+19 J = 2.79 Gigatons (Large Mountain Level)
KE of Cirrus 2 = 0.5*292210868.3*358562.4927^2 = 1.878e+19J = 4.49 Gigatons (Island Level)
Total Output[]
Total KE = 4.49 + 2.79 + 7.41 = 14.69 Gigatons (Island Level)
Updated Results[]
Formula has been changed to "kinetic energy = 1/12 * cloud mass * (Speed of cloud movement)2", so the results will need to be divided by a factor of 6.
New Results: 2.44 Gigatons / 2,444,951,087 Tons (Large Mountain level)