Opened 12 years ago

Closed 12 years ago

#174 closed help (fixed)

difficulty setting up LAM in southern hemisphere

Reported by: anmcr Owned by: um_support
Component: UM Mesoscale Keywords: LAM Southern Hemisphere
Cc: w.mcginty@… Platform:
UM Version:



I used LAMPOS to setup a UM 6.1 LAM centered on the Antarctic Peninsula, defined by

no. cols: 154
no. rows: 214
col spac: 0.11
row spac: 0.11
1st lat: -13.66
1st lon: 351.48
lat pole: 158.86
lon pole: 116.45

I was then able to produce the correct LBCs from a global model, and visualising them using xconv I was able to check that dimensions were correct.

However, the problem I have is that reconfiguration of the global startdump appears to be wrong. And in particular using xconv suggest that the reconfigured startdump has reset the rotated pole to that of a regular lat/lon grid with pole lon =0 deg and pole lat = 90 deg.

1) I read that some applications have difficulty if the rotated pole is greater than 90 deg. Although I don't think that this is why xconv says that the grid has been converted to a regular lat/lon grid.

2) I tried 'mirroring' back to a rotated latitude between 0 and 90oN, using the grid

pole lat: 21.139999
pole lon: 296.449997
1st lat: -13.66
1st lon: 171.48

But this did not seem to work.

Any advice would be gratefully appreciated.


Andrew Orr

Change History (4)

comment:1 Changed 12 years ago by ros

  • Reporter changed from umdoc to anmcr

Andrew, Please remember when you raise tickets in the future to log into the Helpdesk with your username or remember to modify the 'reporter' field to add your email address otherwise the Helpdesk will fail to notify you of any response. I've updated this ticket accordingly for you.

comment:2 Changed 12 years ago by lois

  • Cc w.mcginty@… added

Hello Andrew,
I am not sure quite what question you are asking. You say that your start file after reconfiguration looks 'wrong' in xconv but you don't say if you can run your 12km model with this start file. If the model code is failing then if you could let us know what happens in the model and where the model output is then we see if we can offer some advice.


comment:3 Changed 12 years ago by anmcr

Dear Lois,

I've resolved the problem, and am able to run the LAM over the Southern Hemisphere with a 'mirrored' rotated grid.

I was maybe a bit quick to contact um_support. But thanks for replying.

Best wishes,


comment:4 Changed 12 years ago by willie

  • Resolution set to fixed
  • Status changed from new to closed
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