samirakarbasi
New member
Dear WRF Community,
I am setting up a WRF v4.5.2 simulation over the Iberian Peninsula, specifically focusing on the Valencia region. I am running three nested domains with spatial resolutions of 30 km (d01), 10 km (d02), and 2 km (d03). The simulation periods cover July 2019 (summer) and February 2019 (winter).
My primary question is regarding the grid FDDA (nudging) settings in the &fdda block, specifically for the inner domains (d02 and d03).
I have heard of a "golden rule" in WRF modeling which states that grid nudging should NOT be turned on for high-resolution nested domains. The reasoning is that nudging on inner domains suppresses the fine-scale local topography effects and the detailed meteorological dynamics that the model is trying to resolve, essentially forcing the local physics back to the coarse reanalysis data.
Therefore, is it considered best practice to set grid_fdda = 1, 0, 0 and leave the coefficients for the inner domains at zero?
Here is my proposed
&fdda
View attachment 20846
grid_fdda = 1, 1, 1,
gfdda_inname = "wrffdda_d<domain>",
gfdda_interval_m = 180, 180, 180,
gfdda_end_h = 99999, 99999, 99999,
guv = 0.0003, 0.0003, 0.0003,
gt = 0.0003, 0.0003, 0.0003,
gq = 0.0003, 0.0003, 0.0003,
if_no_pbl_nudging_uv = 1, 1, 1,
if_no_pbl_nudging_t = 1, 1, 1,
if_no_pbl_nudging_q = 1, 1, 1,
if_zfac_uv = 1, 1, 1,
if_zfac_t = 1, 1, 1,
if_zfac_q = 1, 1, 1,
io_form_gfdda = 2,
/
View attachment 20844
Are these assumptions correct? Furthermore, should I keep gq = 0.0 even for domain 1 to avoid artificial moisture effects and precipitation issues, especially during the summer runs?
Any advice on adjusting these coefficients for summer vs. winter would be highly appreciated.
Thanks in advance!
Best regards,
Samira
I am setting up a WRF v4.5.2 simulation over the Iberian Peninsula, specifically focusing on the Valencia region. I am running three nested domains with spatial resolutions of 30 km (d01), 10 km (d02), and 2 km (d03). The simulation periods cover July 2019 (summer) and February 2019 (winter).
My primary question is regarding the grid FDDA (nudging) settings in the &fdda block, specifically for the inner domains (d02 and d03).
I have heard of a "golden rule" in WRF modeling which states that grid nudging should NOT be turned on for high-resolution nested domains. The reasoning is that nudging on inner domains suppresses the fine-scale local topography effects and the detailed meteorological dynamics that the model is trying to resolve, essentially forcing the local physics back to the coarse reanalysis data.
Therefore, is it considered best practice to set grid_fdda = 1, 0, 0 and leave the coefficients for the inner domains at zero?
Here is my proposed
&fdda
View attachment 20846
grid_fdda = 1, 1, 1,
gfdda_inname = "wrffdda_d<domain>",
gfdda_interval_m = 180, 180, 180,
gfdda_end_h = 99999, 99999, 99999,
guv = 0.0003, 0.0003, 0.0003,
gt = 0.0003, 0.0003, 0.0003,
gq = 0.0003, 0.0003, 0.0003,
if_no_pbl_nudging_uv = 1, 1, 1,
if_no_pbl_nudging_t = 1, 1, 1,
if_no_pbl_nudging_q = 1, 1, 1,
if_zfac_uv = 1, 1, 1,
if_zfac_t = 1, 1, 1,
if_zfac_q = 1, 1, 1,
io_form_gfdda = 2,
/
View attachment 20844
Are these assumptions correct? Furthermore, should I keep gq = 0.0 even for domain 1 to avoid artificial moisture effects and precipitation issues, especially during the summer runs?
Any advice on adjusting these coefficients for summer vs. winter would be highly appreciated.
Thanks in advance!
Best regards,
Samira