# Specifying longitudinal and latitudinal ranges in JULES

**URL:** <https://cms-helpdesk.ncas.ac.uk/t/specifying-longitudinal-and-latitudinal-ranges-in-jules/1012>\
**Category:** Uncategorized\
**Created:** [30 May 2023 14:50 UTC](https://cms-helpdesk.ncas.ac.uk/t/specifying-longitudinal-and-latitudinal-ranges-in-jules/1012 "2023-05-30T14:50:58Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![NoelClancy](https://avatars.discourse-cdn.com/v4/letter/n/82dd89/32.png) [@NoelClancy](https://cms-helpdesk.ncas.ac.uk/u/NoelClancy)\
**Post date:** [30 May 2023 14:50 UTC](https://cms-helpdesk.ncas.ac.uk/t/specifying-longitudinal-and-latitudinal-ranges-in-jules/1012/1 "2023-05-30T14:50:58Z")

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How are longitudinal and latitudinal ranges specified in JULES?

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**Author:** ![pmcguire](https://avatars.discourse-cdn.com/v4/letter/p/b782af/32.png) [@pmcguire](https://cms-helpdesk.ncas.ac.uk/u/pmcguire)\
**Post date:** [30 May 2023 19:57 UTC](https://cms-helpdesk.ncas.ac.uk/t/specifying-longitudinal-and-latitudinal-ranges-in-jules/1012/2 "2023-05-30T19:57:44Z")

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You can look at the namelists in the tutorial for the gridded JULES on the UofR Land Surface Processes website. There are some regional settings in the suite described in the suite that are commented out.

So if you open up the file u-as052/app/jules/rose-app.conf in a text editor, you can see the commented out section in model\_grid, and then study the differences, and then uncomment and modify the setting that works for you. For example, the first option below are some good settings for global models, whereas the commented out version below that are some good settings for regionally-limited models:

```auto
[namelist:jules_model_grid]
force_1d_grid=.false.
land_only=.false.
!!lat_bounds=0
!!latlon_region=.false.
!!lon_bounds=0
!!npoints=0
!!points_file=''
use_subgrid=.false.

#[namelist:jules_model_grid]
#force_1d_grid=.false.
#land_only=.false.
#lat_bounds= 45 65
#latlon_region=.true.
#lon_bounds= -10 5
#!!npoints=0
#!!points_file=''
#use_subgrid=.true.

```

Patrick

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**Author:** ![NoelClancy](https://avatars.discourse-cdn.com/v4/letter/n/82dd89/32.png) [@NoelClancy](https://cms-helpdesk.ncas.ac.uk/u/NoelClancy)\
**Post date:** [18 June 2023 19:44 UTC](https://cms-helpdesk.ncas.ac.uk/t/specifying-longitudinal-and-latitudinal-ranges-in-jules/1012/3 "2023-06-18T19:44:38Z")

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How can a single point be specified so that the latitudinal and longitudinal bounds to represent a single site?

For example in u-as052/app/jules/rose-app.conf

Is it possible to run

[namelist:jules\_model\_grid]  
force\_1d\_grid=.false.  
land\_only=.false.  
lat\_bounds=53.32,53.32  
latlon\_region=.true.  
lon\_bounds=-0.6,-0.6  
!!npoints=0  
!!points\_file=‘’  
use\_subgrid=.true.

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<div class="post-metadata">

**Author:** ![pmcguire](https://avatars.discourse-cdn.com/v4/letter/p/b782af/32.png) [@pmcguire](https://cms-helpdesk.ncas.ac.uk/u/pmcguire)\
**Post date:** [19 June 2023 20:27 UTC](https://cms-helpdesk.ncas.ac.uk/t/specifying-longitudinal-and-latitudinal-ranges-in-jules/1012/4 "2023-06-19T20:27:26Z")

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Hi Noel:  
I would be surprised if that works.

The WFDEI grid has grid-cells centered on the 0.25 degrees and 0.75 degrees Lat/Lon.

Maybe instead, you could try it with

```auto
lat_bounds=53.00,53.50
lon_bounds=-1.0,-0.5

```

The WFDEI grid cell boundaries are at multiples of 0.5 degrees Lat/Lon, starting at 0.0, so the values above for lat\_bounds and lon\_bounds will only get the single grid cell centred on 53.25 degrees Lat and -0.75 degrees Lon. It doesn’t do any interpolation, so it isn’t precisely 53.32,-0.6. The sampling is nearest-neighbor.

I think if you use:

```auto
lat_bounds=53.32,53.32
lon_bounds=-0.6,-0.6

```

then there won’t be any points selected, since this region doesn’t contain 53.25,-0.75.

If you’re doing single-point runs, you might consider using a single-point suite (like the loobos one that is frequently quoted) instead of using the gridded JULES suite u-as052. There’s also the single-point suite, u-al752, which you know about, but that uses data at the FLUXNET sites. But you might be interested in doing things with gridded suite u-as052, since maybe the single-points are at non-FLUXNET locations and you want to use WFDEI driving data and the WFDEI ancillaries that are pointed to by the u-as052 suite.

Patrick