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Cloud and radiation interface in CAM6

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lwang

New Member
Hi! We have developed a sectional cloud model for CESM 2. We now need to develop the code linking the cloud model to the RRTMG radiation code. For this reason, we want to know the following information:
– Which codes in CAM6 handle this problem? If we want to modify the radiation code to suit our own cloud model, do we need to modify all of them?
– Which wavelengths RRTMG is using and which refractive index values have been used to couple the MG cloud model to RRTMG. Does anyone have these data, or the off-line code used to generate the Look Up Tables for the MG code?

Many thanks!
 
A

andrew

Member
From Brian Medeiros:

I don’t know how the optics files were generated. You probably know this, but to help answer that forum question:

In the liquid optics file, the bands can be described using the variables that define the bands. For example, the shortwave band centers are given by mid_wvl_sw_band, with the bounds being (wvl_sw_min, wvl_sw_max)…. or the inverse if working in wavenumber.

As far as I have been able to tell, all the files are tailored to match the bands used in RRTMG:

! Shortwave spectral band limits (wavenumbers)
wavenum1(:) = (/2600._r8, 3250._r8, 4000._r8, 4650._r8, 5150._r8, 6150._r8, 7700._r8, &
8050._r8,12850._r8,16000._r8,22650._r8,29000._r8,38000._r8, 820._r8/)
wavenum2(:) = (/3250._r8, 4000._r8, 4650._r8, 5150._r8, 6150._r8, 7700._r8, 8050._r8, &
12850._r8,16000._r8,22650._r8,29000._r8,38000._r8,50000._r8, 2600._r8/)
delwave(:) = (/ 650._r8, 750._r8, 650._r8, 500._r8, 1000._r8, 1550._r8, 350._r8, &
4800._r8, 3150._r8, 6650._r8, 6350._r8, 9000._r8,12000._r8, 1780._r8/)


! Longwave spectral band limits (wavenumbers)
wavenum1(:) = (/ 10._r8, 350._r8, 500._r8, 630._r8, 700._r8, 820._r8, &
980._r8,1080._r8,1180._r8,1390._r8,1480._r8,1800._r8, &
2080._r8,2250._r8,2390._r8,2600._r8/)
wavenum2(:) = (/350._r8, 500._r8, 630._r8, 700._r8, 820._r8, 980._r8, &
1080._r8,1180._r8,1390._r8,1480._r8,1800._r8,2080._r8, &
2250._r8,2390._r8,2600._r8,3250._r8/)
delwave(:) = (/340._r8, 150._r8, 130._r8, 70._r8, 120._r8, 160._r8, &
100._r8, 100._r8, 210._r8, 90._r8, 320._r8, 280._r8, &
170._r8, 130._r8, 220._r8, 650._r8/)


Note that the SW bands are not monotonic because of the last band. These values come from rrtmg_[s,l]w_init.f90.
 
L

lwang

New Member
Thank you Andrew and Brian very much for your info regarding the sw and lw bands. That's very helpful. In case you get further info regarding how the optics files were generated, please let us know. Many thanks!
 
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