How to output MSL pressure, rainfall amount and rainfall rate?

[beuraieon_a]

Hello, I'm actually new to the WRF Model so I'm really struggling with it (thus the multiple posts I've written in the forum). Anyway, I'd like to ask about some variables which, apparently, are not present in the WRFout files. I tried out the Hurricane Matthew single-domain case tutorial, and I want to try it again but using GFS analysis data for another tropical cyclone. Since I still lack some programming skills, I'm visualizing the data using Panoply, with particular focus on wind, pressure and precipitation. I was going to try GrADS but it can't immediately read WRFout files and my ARWpost compilation has failed repeatedly despite different troubleshoot attempts.

Anyway, when I opened the WRFout files in Panoply, I noticed that they do not contain data on mean sea level pressure, rainfall amount and rainfall rate. I observed that there are some pressure-related data (P - perturbation pressure, P_HYD - hydrostatic pressure, PB - base state pressure) contained in WRFout files, but I don't know what to do with them and how to use them to get mean sea level pressure. And I read somewhere that the rainfall-related data in WRFout files (RAINC - accumulated total cumulus precipitation, RAINNC - accumulated total grid scale precipitation, RAINSH - accumulated shallow cumulus precipitation) are rainfall accumulations starting from the initial time of simulation, but not rainfall rate/intensity (in mm/h) nor rainfall amount (in mm, accumulation only for the past 1 hour, past 3 hour or past 6 hour up to the specific time-slice). It also surprised me that RAINNC is not the actual simulation-duration rainfall accumulation, but it is RAINNC + RAINC (I had mistakenly thought all along that RAINNC is already the sum of all cumulus and non-cumulus precipitation).

So I'm wondering, is there a strategy to let the WRF model include mean sea level pressure, rainfall rate/intensity and rainfall amount in the WRFout files? Do I have to change some values in the namelist files, Vtables, GEOGRID.TBL etc.? If so, how do I set these variables? Or if it has something to do with post-processing, what are the best strategies relevant to these needed meteorological parameters?

Your comments, advise or recommendations regarding this query is very much appreciated. Thank you very much, and may you all have a nice day ahead.

 

[kwerner]

Hi,
I believe the WRF Output chapter of the WRF Users' Guide may provide some useful information.
As an alternative to ARWpost, which hasn't been developed in several years now, you could use NCL, which already has several scripts available. These may at least get you close to obtaining the information you desire.

 

[beuraieon_a]

Hello, Sir. Thank you very much for sharing these information. They're quite helpful, and I'm going to try using these functionalities soon to see if they suit my needs. I also have NCL already present in my computer, but I have not used it yet; it might take time for me to learn and be accustomed to it.

I would like to ask some follow-up questions about this:

1. What is "total pressure"?

If my understanding of the WRF Output chapter is correct, mean sea level pressure (MSLP) is still not included in WRFout files, even in the various WRF output diagnostics, which somehow saddens me since MSLP is quite a basic meteorological variable and it's not present in the model output itself.

Nevertheless, I'm curious about "total pressure", which is one of the special WRF output variables. What do we mean by "total pressure"? And how is it different from MSLP?

2. Does "prec_acc_dt = 60" means I can let my WRFout files contain hourly rainfall amount data?

Miscellaneous Output Options

do_radar_ref = 1: Add to &physics to compute radar reflectivity using microphysics-specific parameters in the model.
This option works with mp_physics= 2, 4, 6, 7, 8, 10, 14, 16, 17, 18, 19, 21, 24, 26, 28

prec_acc_dt = 60 : Add to &physics to provide a time interval for outputting precipitation variables (rain from cumulus and microphysics schemes, and snow from microphysics), in minutes.

Just to check my understanding, does "prec_acc_dt = 60" means I can set my WRF model to provide output data on hourly precipitation amounts, or does it still output precipitation as simulation-duration accumulations but only written in hourly intervals to the WRFout files?

3. Is there a reason why MSLP, rainfall rate/intensity (in mm/h) and rainfall amount (in mm, accumulation only for the past 1 hour, past 3 hour or past 6 hour up to the specific time-slice/observation time) are not immediately included as output in the WRF Model, despite them being basic meteorological variables?
- Is this somehow part of WRF's current limitations, or is this related to how WRF processes the input data to produce the model output?
- Is it possible that these meteorological variables be included as model outputs in future software updates of the WRF Model?

Any comments, advise or recommendations about these inquiries are very much appreciated. Thank you very much!

 

[beuraieon_a]

Hello, I'm currently trying out the AFWA weather diagnostics in my WRF model run. I checked out "registry.AFWA" and I noticed that apparently it allows for outputting MSLP and some precipitation-related variables. I hope this works out without any errors. Thank you!

 

[beuraieon_a]

Hello, I have successfully generated additional variables in my WRFout files, including mean sea level pressure and past 1-hour rainfall amount. The WRF output diagnostics really helped. Thank you very much for your recommendations and advise!