CLM-Community

Dear Simon, I am afraid, there will not be the “one and only” parameter that might improve your results. However, I have, at first, two suggestions, which you can try, and which require re-calculations of CCLM only. That means, you can further use your forcing data that you have calculated with INT2LM The first suggestion: one tuning parameter, which might be of interest, is “rat_sea”, which has a default value of 20, which you have used. Decrease this parameter to the lowest value, which is allowed: rat_sea=1. My experience is, that decreasing the value of rat_sea increases the precipitation; however, in my sensitivity runs for Africa the increase was not very large. The second suggestion: increase the parameter “rdheight” from 11000.0 m to 15000.0. rdheight has to be defined in Namelist group DYNCTL . The value of 11000.0 is the default, so it might be possible that it is not set in your run-script. You have to do this if you change the default value. According to the height of your model domain (22700 m), a value of 15000.0 for rdheight is the maximum that makes sense. Perhaps you remember our discussion in Zurich last year where I explained why we had to increase the rdheight value over the CORDEX Africa domain, which includes tropics and sub-tropics. Without this increase the precipitation was very much too low. For your case, I expect a larger impact from the increase of rdheight than from the decrease of rat_sea. Attached you find a YUSPECIF file from our CORDEX Africa evaluation runs. There you can find further differences between your CCLM setup and the CORDEX setup. If you like, study the impact of further adaptations to the CORDEX Africa setup. Coming back to the height of your model domain. Looking at the geography of your model domain I doubt a little bit that the choice of 22700m for the top of the domain is appropriate. For CORDEX Africa we chose 30000. But if you want to change the vertical grid, you have to re-run INT2LM, since the verical grid is defined in INT2LM, not in CCLM . Without changing your number of vertical levels (40) and the thickness of the lowest layer (20m), the following vertical grid could be reasonable (has to be defined in INT2LM, Namelist Group LM_GRID) vcoord_d= 30000.00, 27800.00, 25710.00, 23730.00, 21860.00, 20080.00, 18410.00, 16830.00, 15350.00, 13960.00, 12660.00, 11440.00, 10300.00, 9250.00, 8265.00, 7360.00, 6520.00, 5750.00, 5045.00, 4400.00, 3820.00, 3290.00, 2815.00, 2390.00, 2015.00, 1680.00, 1388.00, 1134.00, 915.00, 729.00, 573.00, 443.00, 338.00, 253.00, 186.00, 134.00, 95.00, 64.00, 41.00, 20.00, 0.00 Hans-Juergen

#9469293

@hans-jürgenpanitz in #9469293
 Dear Simon, I am afraid, there will not be the “one and only” parameter that might improve your results. However, I have, at first, two suggestions, which you can try, and which require re-calculations of CCLM only. That means, you can further use your forcing data that you have calculated with INT2LM The first suggestion: one tuning parameter, which might be of interest, is “rat_sea”, which has a default value of 20, which you have used. Decrease this parameter to the lowest value, which is allowed: rat_sea=1. My experience is, that decreasing the value of rat_sea increases the precipitation; however, in my sensitivity runs for Africa the increase was not very large. The second suggestion: increase the parameter “rdheight” from 11000.0 m to 15000.0. rdheight has to be defined in Namelist group DYNCTL . The value of 11000.0 is the default, so it might be possible that it is not set in your run-script. You have to do this if you change the default value. According to the height of your model domain (22700 m), a value of 15000.0 for rdheight is the maximum that makes sense. Perhaps you remember our discussion in Zurich last year where I explained why we had to increase the rdheight value over the CORDEX Africa domain, which includes tropics and sub-tropics. Without this increase the precipitation was very much too low. For your case, I expect a larger impact from the increase of rdheight than from the decrease of rat_sea. Attached you find a YUSPECIF file from our CORDEX Africa evaluation runs. There you can find further differences between your CCLM setup and the CORDEX setup. If you like, study the impact of further adaptations to the CORDEX Africa setup. Coming back to the height of your model domain. Looking at the geography of your model domain I doubt a little bit that the choice of 22700m for the top of the domain is appropriate. For CORDEX Africa we chose 30000. But if you want to change the vertical grid, you have to re-run INT2LM, since the verical grid is defined in INT2LM, not in CCLM . Without changing your number of vertical levels (40) and the thickness of the lowest layer (20m), the following vertical grid could be reasonable (has to be defined in INT2LM, Namelist Group LM_GRID) vcoord_d= 30000.00, 27800.00, 25710.00, 23730.00, 21860.00, 20080.00, 18410.00, 16830.00, 15350.00, 13960.00, 12660.00, 11440.00, 10300.00, 9250.00, 8265.00, 7360.00, 6520.00, 5750.00, 5045.00, 4400.00, 3820.00, 3290.00, 2815.00, 2390.00, 2015.00, 1680.00, 1388.00, 1134.00, 915.00, 729.00, 573.00, 443.00, 338.00, 253.00, 186.00, 134.00, 95.00, 64.00, 41.00, 20.00, 0.00 Hans-Juergen

CCLM for Middle East with ERA Interim – in #9: CCLM

in #9: CCLM

Cookies disclaimer

Unread

Cookies disclaimer