Unrealistic temperature values

[llsalazardom]

Good morning,

We have been running WRF v4.4 using ECMWF data for initial and boundary conditions. Our main variable of interest is temperature, but we encountered a strange behavior. We ran a simulation over the Strasburg area on 2018-08-07 for 24 hours, and observed a minimum temperature value of 0.010650634765625 at hour 17.
We repeated the same test on a different machine, and this extremely low value also appeared, but at a different hour. Such a low temperature is highly improbable for August.
We checked the ECMWF data and found nothing wrong.
Could anyone help us determine what might be causing this issue in our simulation?

I'm attaching the namelist* files and listing the temperature values from both machines.
Thank you in advance for any help

Machine 1:
Hours Minimum values Latitude Longitude Maximum values
wrfout_d02_2018-08-07_12:00:00 16.3673095703125 48.453846 7.7239685 35.060272216796875
wrfout_d02_2018-08-07_13:00:00 17.17559814453125 48.453846 7.7239685 35.444305419921875
wrfout_d02_2018-08-07_14:00:00 16.485565185546875 48.761185 6.9374695 35.805511474609375
wrfout_d02_2018-08-07_15:00:00 16.352935791015625 48.77017 6.937439 35.667266845703125
wrfout_d02_2018-08-07_16:00:00 16.66339111328125 48.761185 6.9374695 35.216552734375
wrfout_d02_2018-08-07_17:00:00 0.010650634765625 48.47166 7.7513123 34.530975341796875
wrfout_d02_2018-08-07_18:00:00 15.9447021484375 48.43594 7.710205 33.254730224609375
wrfout_d02_2018-08-07_19:00:00 15.0035400390625 48.77017 6.937439 31.68829345703125
wrfout_d02_2018-08-07_20:00:00 15.558349609375 48.48064 7.7514343 30.381195068359375
wrfout_d02_2018-08-07_21:00:00 14.149658203125 48.45391 7.7104187 29.66778564453125
wrfout_d02_2018-08-07_22:00:00 14.33941650390625 48.453846 7.7239685 29.517486572265625
wrfout_d02_2018-08-07_23:00:00 13.442962646484375 48.453846 7.7239685 29.088653564453125

Machine 2:
Hours Minimum values Latitude Longitude Maximum values
wrfout_d02_2018-08-07_12:00:00 16.46478271484375 48.453846 7.7239685 35.118865966796875
wrfout_d02_2018-08-07_13:00:00 17.3836669921875 48.453846 7.7239685 35.56463623046875
wrfout_d02_2018-08-07_14:00:00 16.04595947265625 48.761185 6.9374695 35.7860107421875
wrfout_d02_2018-08-07_15:00:00 16.67926025390625 48.77017 6.937439 35.72918701171875
wrfout_d02_2018-08-07_16:00:00 16.655517578125 48.761185 6.9374695 35.198089599609375
wrfout_d02_2018-08-07_17:00:00 18.1243896484375 48.080566 8.311249 34.522308349609375
wrfout_d02_2018-08-07_18:00:00 13.189483642578125 48.453682 7.751068 32.998687744140625
wrfout_d02_2018-08-07_19:00:00 0.010650634765625 48.435867 7.7237244 31.097747802734375
wrfout_d02_2018-08-07_20:00:00 14.41424560546875 48.48064 7.7514343 30.179443359375
wrfout_d02_2018-08-07_21:00:00 14.15191650390625 48.453846 7.7239685 29.824371337890625
wrfout_d02_2018-08-07_22:00:00 14.444183349609375 48.453846 7.7239685 29.464111328125
wrfout_d02_2018-08-07_23:00:00 13.576904296875 48.45391 7.7104187 29.226776123046875

 

[kwerner]

Apologies for the long delay in response while our team tended to time-sensitive obligations. Thank you for your patience.

Have you tried to use different physics options to see if the issue could be related to a specific physics scheme?

 

[llsalazardom]

Hi, thanks for your replay

No, I didn’t try using different physics options because I thought it was unlikely that the physics options would affect only one hour at a single point. Is that even possible?

 

[meteoadriatic]

Hello,

As this happens around the boundary of a water body, and it is ECMWF input, please try to remove SST from your Vtable and check again if the issue persists.