Hello all,
Greetings!
This is a researcher currently working with a raft of WRF (version3.61) output files with hourly output frequency in a previously conducted WRF simulation (Feng et al. 2018). The simulation was done with 4-km horizontal resolution and 65 vertical layers. Simulation period is from 1 May 2011 to 31 August 2011. Other setup configurations are as follows:
The lateral and surface forcing: Global Forecast System Reanalysis.
PBL scheme: YSU.
Surface scheme: MM5.
Land surface model: Noah Land Surface model.
Longwave radiation scheme: RRTMG.
Shortwave radiation scheme: Goddard shortwave scheme.
MIcrophysics: Morrison 2-moment; Thompson.
I was following some posts on alternative ways to reconstruct surface energy budget and found the following posts to be enlightening!
https://forum.mmm.ucar.edu/phpBB3/viewtopic.php?f=43&t=10014&p=20146&hilit=ALBEDO#p20146
https://forum.mmm.ucar.edu/phpBB3/viewtopic.php?f=43&t=5674&p=13582&hilit=heat+budget#p13582
https://forum.mmm.ucar.edu/phpBB3/viewtopic.php?f=57&t=5532&p=10650&hilit=ALBBCK#p10650
In short, the WRF output files I have did not have enough variables to directly calculate various terms of the surface energy balance. However, I’m hoping to do it indirectly by following an approach suggested by Kelly in one of the posts as follows:
gsw = (1-ALBEDO) * SWDOWN
glw = GLW
lwupflux = np.power(TSK,4) * STBOLT
netlw = EMISS*(glw-lwupflux)
netrad = gsw + netlw
seb = netrad + GRDFLX -HFX -LH
I found a portion of variables required in this framework are available in the current WRF outputs I possess, including surface skin temp (TSK), downward SW flux at ground (SWDOWN), downward LW flux at ground (GLW), and ground heat flux (GRDFLX). Some other variables required in this framework but are not in the WRF output files are ALBEDO and surface emissivity (EMISS).
With respect to ALBEDO, the WRF outputs do have background albedo "ALBBCK". Given that the ALBEDO is missing, it's tantalizing to use ALBBCK as a proxy. However, from previous post in the forum and some sniff tests suggest that these two variables (ALBBCK, ALBEDO) are different and their values differ. From the third posts mentioned above. Kelly posted:
"ALBBCK is the monthly albedo map that comes from the geogrid program, and ALBEDO is based on the surface model, and comes from the table values that model uses. If usemonalb = .true. the model uses ALBBCK instead of ALBEDO. After running, you would still want to look at the variable ALBEDO because the model will fill the ALBEDO array with the values from ALBBCK."
With respect to EMISS, in the user guide of a more recent version WRF AWR [version 4, Jan 2019], the following piece of information might be relevant.
Chapter "6. WRF Data Assimilation"
Section of "Radiance Data Assimilation in WRFDA"
"c. Radiative Transfer Models"
"The RTTOV package is not distributed with WRFDA, due to licensing restrictions. Users need to follow the instructions at http://nwpsaf.eu/site/software/rttov/ to download the RTTOV source code and supplement coefficient files and the emissivity atlas dataset."
It seems to suggest there's some kind of emissivition atlas datasets.
In short, the questions are:
(1) Are these two variables (EMISS, ALBEDO) obtained from external or intermediate files somewhere under the hood in the WRF runs?
(2) Are there certain ways one could obtain or derive the EMISS and/or ALBEDO information offline with hourly frequency in a previously conducted WRF (v3.61) simulation? (please see the beginning of the post for setup configurations)
(4) Are the two variables interactively calculated by the WRF model (so that they're difficult to get offline)? What additional information is needed to reproduce or retrieve the EMISS and ALBEDO information?
Thank you very much for your help!
Kind regards,
Hongchen
Reference
Feng, Z., Leung, L. R., Houze, R. A., Hagos, S., Hardin, J., Yang, Q., et al. (2018). Structure and Evolution of Mesoscale Convective Systems: Sensitivity to Cloud Microphysics in Convection‐Permitting Simulations Over the United States. Journal of Advances in Modeling Earth Systems, 10(7), 1470–1494. https://doi.org/10.1029/2018MS001305
Greetings!
This is a researcher currently working with a raft of WRF (version3.61) output files with hourly output frequency in a previously conducted WRF simulation (Feng et al. 2018). The simulation was done with 4-km horizontal resolution and 65 vertical layers. Simulation period is from 1 May 2011 to 31 August 2011. Other setup configurations are as follows:
The lateral and surface forcing: Global Forecast System Reanalysis.
PBL scheme: YSU.
Surface scheme: MM5.
Land surface model: Noah Land Surface model.
Longwave radiation scheme: RRTMG.
Shortwave radiation scheme: Goddard shortwave scheme.
MIcrophysics: Morrison 2-moment; Thompson.
I was following some posts on alternative ways to reconstruct surface energy budget and found the following posts to be enlightening!
https://forum.mmm.ucar.edu/phpBB3/viewtopic.php?f=43&t=10014&p=20146&hilit=ALBEDO#p20146
https://forum.mmm.ucar.edu/phpBB3/viewtopic.php?f=43&t=5674&p=13582&hilit=heat+budget#p13582
https://forum.mmm.ucar.edu/phpBB3/viewtopic.php?f=57&t=5532&p=10650&hilit=ALBBCK#p10650
In short, the WRF output files I have did not have enough variables to directly calculate various terms of the surface energy balance. However, I’m hoping to do it indirectly by following an approach suggested by Kelly in one of the posts as follows:
gsw = (1-ALBEDO) * SWDOWN
glw = GLW
lwupflux = np.power(TSK,4) * STBOLT
netlw = EMISS*(glw-lwupflux)
netrad = gsw + netlw
seb = netrad + GRDFLX -HFX -LH
I found a portion of variables required in this framework are available in the current WRF outputs I possess, including surface skin temp (TSK), downward SW flux at ground (SWDOWN), downward LW flux at ground (GLW), and ground heat flux (GRDFLX). Some other variables required in this framework but are not in the WRF output files are ALBEDO and surface emissivity (EMISS).
With respect to ALBEDO, the WRF outputs do have background albedo "ALBBCK". Given that the ALBEDO is missing, it's tantalizing to use ALBBCK as a proxy. However, from previous post in the forum and some sniff tests suggest that these two variables (ALBBCK, ALBEDO) are different and their values differ. From the third posts mentioned above. Kelly posted:
"ALBBCK is the monthly albedo map that comes from the geogrid program, and ALBEDO is based on the surface model, and comes from the table values that model uses. If usemonalb = .true. the model uses ALBBCK instead of ALBEDO. After running, you would still want to look at the variable ALBEDO because the model will fill the ALBEDO array with the values from ALBBCK."
With respect to EMISS, in the user guide of a more recent version WRF AWR [version 4, Jan 2019], the following piece of information might be relevant.
Chapter "6. WRF Data Assimilation"
Section of "Radiance Data Assimilation in WRFDA"
"c. Radiative Transfer Models"
"The RTTOV package is not distributed with WRFDA, due to licensing restrictions. Users need to follow the instructions at http://nwpsaf.eu/site/software/rttov/ to download the RTTOV source code and supplement coefficient files and the emissivity atlas dataset."
It seems to suggest there's some kind of emissivition atlas datasets.
In short, the questions are:
(1) Are these two variables (EMISS, ALBEDO) obtained from external or intermediate files somewhere under the hood in the WRF runs?
(2) Are there certain ways one could obtain or derive the EMISS and/or ALBEDO information offline with hourly frequency in a previously conducted WRF (v3.61) simulation? (please see the beginning of the post for setup configurations)
(4) Are the two variables interactively calculated by the WRF model (so that they're difficult to get offline)? What additional information is needed to reproduce or retrieve the EMISS and ALBEDO information?
Thank you very much for your help!
Kind regards,
Hongchen
Reference
Feng, Z., Leung, L. R., Houze, R. A., Hagos, S., Hardin, J., Yang, Q., et al. (2018). Structure and Evolution of Mesoscale Convective Systems: Sensitivity to Cloud Microphysics in Convection‐Permitting Simulations Over the United States. Journal of Advances in Modeling Earth Systems, 10(7), 1470–1494. https://doi.org/10.1029/2018MS001305