Hi All @cchambers and I are attempting to run a shifted domain AUS2200 configuration, and we’re having issues around the creation of the vegetation fraction ancils. What seems to be happening is that one of the plant functional types has a huge number of unresolved points (~27k) out to a search rad…

That seems likely, the MODIS dataset is at 4km and we’re working with a 2.2km land mask derived from SRTM orography. Unfortunately the ancil code linearises the data, so all I know is that some points around 3,039,384 seem to take the longest to resolve. If my maths is right, that’s about 26.1S, 156…

My maths was completely wrong, point 3,039,384 corresponds to 29.0S, 167.9E, and there is a little island Norfolk Island there which is completely missing from the MODIS dataset.

A quick update before the long weekend, I’ve made a test land mask without Norfolk Island and it did not solve the issue. In the interest of expedience @cchambers has shifted the domain centre to 140E which appears to remove the area causing the problem, so that gives us an idea where the issues lie…

I looked at this a bit further on Thursday evening, and it turns out that the issue is New Zealand. This is the shifted domain @cchambers has been attempting to use. [Aus2200_shifted] I’ve verified that the 27,463 unresolved points correspond to the bit of New Zealand visible in the bottom right o…

From decoding the cap source: from typing import BinaryIO import numpy def read_igbp(f: BinaryIO): """ Reads UKMO IGBP master data file """ igbp = {} igbp['points_lambda_srce'] = int(f.read(5)) f.read(1) igbp['points_phi_srce'] = int(f.read(5)) igbp['phi_origin_srce…

So after further digging, what @MartinDix said in our meeting a couple of weeks ago was correct, ANTS is used to create the veg_frac ancil, however, CAP is still used to create the soil ancil. CAP’s workflow is veg_frac/veg_func → land ice correction → soil, so this whole thing is getting hung up on…

[image] Scott: IGBP_CLASS Hi all. Just bumping this because we’ve found similar issues when attempting to use Chermelle’s regional nesting suite over Gippsland and the Tasman Sea. Scott - can you point me to the source code where you grabbed the IGBP classifications? Thanks

https://code.metoffice.gov.uk/trac/ancil/browser/main/trunk/src/code/igbp_veg/select_igbp_class.F

@Paul.Gregory have you tried the ants.analysis.make_consistent_with_lsm function? https://code.metoffice.gov.uk/doc/ancil/ants/0.16/analysis.html#ants.analysis.make_consistent_with_lsm I haven’t tried this with soil ancils, but seems to do the job with land_frac.

No I have not! Thanks for pointing that out to me, I will try it out.

AUS2200 vegetation fraction ancil creation issues

Atmosphere AUS2200

Aidan (Aidan Heerdegen, ACCESS-NRI Release Team Lead) 19 November 2024 01:13 24

Not that data in /scratch/public is deleted after 2 weeks, so grab a copy ASAP if you need it

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AUS2200 vegetation fraction ancil creation issues

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