Hot answers tagged

17 votes
Accepted

Why is WRF most often configured at 3:1 nesting ratio?

To understand why the nesting ratio of 3 is preferred to the nesting ratio of 2, it is important to understand the following two features of WRF: 1) Grids are Arakawa C-staggered: mass points are at ...
milancurcic's user avatar
  • 4,983
9 votes

Does finer input data lead to a better model accuracy?

My experience with the WRF is in tropical cyclone simulation, but here are some things to consider: Smaller scale information might already be resolved in your higher resolution initial conditions, ...
jgadoury's user avatar
  • 315
8 votes
Accepted

Why does computation cost increase 24 times when the spatial resolution doubles?

I can't answer why there's a 24x increase, according to the textbook - but it may well be the case for a specific model. In general, If you double the resolution of a 3D model in each dimension, you ...
Semidiurnal Simon's user avatar
7 votes
Accepted

Calculate precipitation from WRF model output

Use (1) Precipitation, as it is the sum of convective and non-convective precipitation, integrate it over one day, voilà. converting [$kg/(m^2 s)$] (precip): $$ precip [kg/(m^2 s)] \cdot dt [s] \cdot ...
Lukas's user avatar
  • 438
7 votes

Does finer input data lead to a better model accuracy?

Yes, of course finer input data can lead to better model accuracy, but only if the model's conceptualization is close to the mark. Of the many problems of climatic model misinterpretation, I would ...
Gordon Stanger's user avatar
6 votes

regeride netcdf file to template netcdf file resoulution

Disclaimer: I have not looked at your particular files. You can regrid the data in Python using the NetCDF-4 module. If you want to interpolate vertically, you can use the WRF module. And for ...
BarocliniCplusplus's user avatar
6 votes
Accepted

What denotes a parameterization in a model? (semantics )

As defined in the AMS glossary, a parameterization is a simplification of one or several processes in a model. I add that a parameterization commonly adds an error and increases the uncertainty in the ...
daniel.heydebreck's user avatar
5 votes
Accepted

Running WRF with ECMWF GRIB2 model levels

I finally solved this problem with the following steps: Download the ECMWF data separately for model level variables (Q,T,U,V and geopotential) and surface variables. In this way, you will get 'pure' ...
Peter9192's user avatar
  • 201
5 votes

Does WRF simulation use sigma or eta vertical coordinate system?

WRF is using the sigma (terrain-following) vertical coordinate. However, as @gansub has already referred, in WRF V3.9 you can now select a hybrid sigma-pressure vertical coordinate. The advantage of ...
Whir's user avatar
  • 451
4 votes

Longitudes and latitudes are not regular in WRF-out files

I am not sure about your R code or your snippet of data. However, you could do an ncdump on the file and direct the output to text to get it "from the horses mouth" so to speak. In general, the lat/...
f.thorpe's user avatar
  • 13.5k
4 votes

ECMWF data as WRF input

For any of the basic forecast runs (10 day, ensembles, monthly/seasonal forecasts), I do not believe ECMWF data access is general controlled to ECMWF.INT. Generally most data, including anywhere near ...
JeopardyTempest's user avatar
4 votes

Why is WRF-Chem not reading my emissions data?

I could run model, i just had to change a bit the namelist. I added three parameters:io_form_auxinput5 = 2,auxinput5_inname = 'wrfchemi_d$<domain>$_$<date>$' and frames_per_auxinput5 ...
Sergio's user avatar
  • 412
3 votes
Accepted

How to install WRF on a Mac?

The WRF Forum here describes some testing using a Mac, and they report success with 2 setups: Mac 64-bit running OSX, with Intel chips, g95 gcc version 4.0.3 (g95 0.92!) Mac 64-bit running OSX, with ...
f.thorpe's user avatar
  • 13.5k
3 votes
Accepted

Can the dew point temperature be more than drybulb temperature?

Dew point gives an indication of the moisture content of air; it is the temperature at which air can no longer hold water vapour. The following graph shows the relations of dew point to air ...
Fred's user avatar
  • 24.7k
2 votes

How to set up a domain from namelist in WRF?

There is a WRF domain Wizard offered by ESRL. You can download it here. Also, don't make the same mistake I made using Lambert Conformal- keep stand_lon the same as your ref_lon.
BarocliniCplusplus's user avatar
2 votes
Accepted

Technique to delete spin-up frames from WRF

There is an feature of the -d option that makes the call of ncks redundant. However, it is available since NCO version 4.2.1 (...
daniel.heydebreck's user avatar
2 votes

Technique to delete spin-up frames from WRF

Here is my present approach. All wrfout-files are located in the same path. Using pynco in python loop to split the spin-up dataframe ...
Han Zhengzu's user avatar
  • 2,459
2 votes

How to map emission inventory from lat&lon corrdinate to WRF model grid

I would suggest using cdo for your purpose. At least for variables, which values are independent of the grid cell size, one can use cdo. cdo cdo (Climate Data Operators) is a command line program to ...
daniel.heydebreck's user avatar
2 votes

How to properly setup a domain in NWP model (WRF) according to meteorological input data

A good rule of thumb for down-scaling with WRF is not to interpolate down more than 3 or 4 times; with 3 being the standard recommendation. So while 18 km is probably overkill for an outer domain (...
Mike Kavulich's user avatar
2 votes
Accepted

Wind speed data plot contains blank gaps

The answer is actually pretty easy. The WRF model lies on a grid. The vertical component of the grid is unevenly spaced, though you can manually space it. The vertical coordinate of WRF uses a sigma ...
BarocliniCplusplus's user avatar
2 votes
Accepted

Spatial allocation of road emissions and unit conversion

You have got your emissions over a square kilometer. To get to square meters you divide by 1000000 since $1km^2=10^6m^2$.
Christoph's user avatar
  • 994
2 votes
Accepted

WRF/Chem: Editing NetCDF (wrfchemi files) for own emissions

You can try the R package eixport, with wrf_put ...
Sergio's user avatar
  • 412
2 votes

How to find the top level of the planetary boundary layer in WRF?

Well, the variable PBLH should tell you the PBL height. If you want the level that the PBL is, I suggest modifying the Registry.EM_COMMON file. Perhaps I can refer ...
BarocliniCplusplus's user avatar
1 vote

How to de-stagger (or unstagger) WRF wind fields?

The simplest way I've found in Python is to use the getvar function with the 'ua,' 'va,' or 'wa' variables from the WRF-Python module. Alternatively, you can take the midpoint between the staggers. ...
BarocliniCplusplus's user avatar
1 vote
Accepted

WRF: EPSG code or spatial reference for Lambert conformal, Mercator and polar stereographic projections

Spatial reference systems are coordinate systems that can be geographical coordinate systems defined on a model ellipsoid or projection coordinate systems. A projection coordinate system is defined ...
Dima Chubarov's user avatar
1 vote

How to map emission inventory from lat&lon corrdinate to WRF model grid

using R: Alright, As you have data with different resolution, I would suggest you to convert your data to raster and resample to match the grid cell of your wrf_inputs. Take care of mass ...
Sergio's user avatar
  • 412
1 vote

run the WRF model using ERA5

Did you use the right Vtable? That error message is saying that the soil temperature variable is missing/couldn't be read.
BarocliniCplusplus's user avatar
1 vote

Does thermal bubble initiated in WRF dissipate over time?

After initialization the model calculates forward in time ncluding all physical processes represented by your setup of WRF. This probably means that the warm air will rise and thereby trigger the ...
Basileios's user avatar
  • 407
1 vote

ECMWF data as WRF input

Here is a Python Script showing how to download the required variables automatically. http://conorsweeneyucd.blogspot.com/2015/01/download-era-interim-data.html
Xiao Yu's user avatar
  • 11

Only top scored, non community-wiki answers of a minimum length are eligible