calculation of longwave radiation in BULK_FLUX.F code

[syuip1224]

Dear ROMS users,

I have a question about calculation of longwave radiation in BULK_FLUX.F code.

I define BULK_FLUXES and LONGWAVE_OUT in ROMS(version 3.5) with ice model.

#define BULK_FLUXES
#define LONGWAVE_OUT
#define ICE_MODEL
#define ICE_THERMO.

In this case, net longwave radiation (LRad) is computed by

LRad(i,j) = lrflx(i,j)*Hscale - emmiss*StefBo*TseaK(i)*TseaK(i)*TseaK(i)*TseaK(i)

in BULK_FLUX.F code.
The input data for lrflx(longwave_down) is ECMWF "surface thermal radiation downwards".


Next, net longwave radiation from "ICE" is computed by

qlwi = lrflx(i,j)*Hscale

and qlwi is used to calculate Qai(qai_n for ICE_MK.h).

My question is, there exists only "downwelling longwave radiation" for ice surface?
Why doesn't it involve the term expressing outgoing longwave radiation?
I think, there also exists outgoing longwave radiation from ice surface.
If so, Do I need to change the code? like this,

# elif defined LONGWAVE_OUT

qlwi = lrflx(i,j)*Hscale - emmiss(for ice)*StefBo*TiceK(i)*TiceK(i)*TiceK(i)*TiceK(i)

# else

qlwi = lrflx(i,j)*Hscale

# endif
'TiceK' is the ice(or snow) surface temperature.


Any comments and suggestions would be greatly appreciated.

Thanks for your helps.

- SY

[kate]

The outgoing longwave flux is in there. If not, you'd get much stranger results! However, the code solves for the surface ice temperature as part of the solution technique so it looks rather different, being a term in the Taylor series expansion about (Tice-Tair). I was recently reminded of this by another user who was puzzled by this.

[syuip1224]

Thanks for your kindness help!