Scheduled Downtime
On Friday 21 April 2023 @ 5pm MT, this website will be down for maintenance and expected to return online the morning of 24 April 2023 at the latest

Radiation in Real-data WRF


New member
Hello everyone,

As a sensitivity experiment, I would like to investigate the effects of long-wave radiation (specifically, cloud top radiative cooling and cloud base radiative heating) on the development of a mesocyclone. The first option that comes to mind is to simply turn off the long-wave radiation scheme (ra_lw_physics = 0), but the simulation fails shortly after initialization with the following error: The longwave option does not exist... From an earlier post (WRF Radiation), it seems that the radiation schemes cannot be turned off in a real-data case. Are there still options that may be available to carry out my experiment, such as simple adjustments to the source code or potential work arounds? For example, can the time step between radiation physics calls (radt) be larger than the time domain of the simulation (in my case, 48 hours)? Naively, I assume this is effectively the same as setting ra_lw_physics = 0. Note that my simulations occur during the winter season in the Arctic, so short-wave radiation is negligible.

Also, is it possible to make clouds transparent to long-wave radiation? This would seem to be the purpose of the icloud option.

Thanks in advance for your insights!