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APS1 & 2 city model land sea masks #258

Open penguian opened 8 years ago

penguian commented 8 years ago

| by mrd599@nci.org.au

The IGBP land cover data used to generate the land sea masks has position errors that show up in the 4 and 1.5 km models.

This ticket will investigate how best to either correct this or use alternate data sources.

Issue migrated from trac:258 at 2024-01-31 18:22:28 +1100

penguian commented 8 years ago

@martin.dix@anu.edu.au changed status from new to assigned

penguian commented 8 years ago

@martin.dix@anu.edu.au changed owner from ` tomrd599`

penguian commented 8 years ago

@martin.dix@anu.edu.au commented

Tomasz flagged problems with the APS1 AN land sea mask having ocean all around the Cape Willoughby station on Kangaroo Island. Maps shows the model mask and orography with the GA coastline.

CapeWilloughby_APS1_AN.png

The ancillary program calculates the mask from the IGBP 1 km land surface classification dataset. This has displacement errors (https://code.metoffice.gov.uk/trac/TI/ticket/2) and worse the errors vary with location. Near Kangaroo Is. there seems to be an offset of about 2 km W and 1 km S.

igbp_kangaroo_island.png

By comparison there's no problem with the GA 250 m orography orog_9s_kangaroo_island.png

penguian commented 8 years ago

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penguian commented 8 years ago

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penguian commented 8 years ago

@martin.dix@anu.edu.au _uploaded file CapeWilloughby_APS1_AN.png (31.9 KiB)_

APS1 orography and mask around Cape Willougby station

penguian commented 8 years ago

@martin.dix@anu.edu.au _uploaded file orog_9s_kangaroo_island.png (69.1 KiB)_

GA 9s orography for Kangaroo Is.

penguian commented 8 years ago

@martin.dix@anu.edu.au _uploaded file igbp_kangaroo_island.png (36.3 KiB)_

IGBP surface type for Kangaroo Is.

penguian commented 8 years ago

@martin.dix@anu.edu.au commented

Usual APS city mask generation uses IMETHOD=2 for data aggregation, https://code.metoffice.gov.uk/doc/ancil/ancil9.0/ATDP/ATDP01.html#agregation (most of the non-variable grid Met Office LAM configurations also use this).

With IMETHOD=5 there's options for X and Y offsets of the IGBP data, https://code.metoffice.gov.uk/doc/ancil/ancil9.0/ATDP/ATDP01.html#atdp01-ancilscr-mask-land-sea-masks.

This is designed to work around the offset problems we have here.

https://code.metoffice.gov.uk/trac/ancil/ticket/72 is a open request to add this capability to method 2 but for now we have to use method 5 for the offsets.

The same aggregation method is used for the vegetation properties so the same offsets should be used there.

penguian commented 8 years ago

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penguian commented 8 years ago

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penguian commented 8 years ago

@martin.dix@anu.edu.au commented

In the longer term, the Met Office are considering replacing the IGBP data with CCI from ESA, http://www.esa-landcover-cci.org/. This has 300m resolution.

Plotting this with the GA coastline shows no alignment problems.

cci_kangaroo_island.png

Color key at http://maps.elie.ucl.ac.be/CCI/viewer/download/CCI-LC_Maps_Legend.pdf

penguian commented 8 years ago

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penguian commented 8 years ago

@martin.dix@anu.edu.au _uploaded file cci_kangaroo_island.png (48.2 KiB)_

penguian commented 8 years ago

@martin.dix@anu.edu.au commented

Tools for working with masks now in repository https://code.metoffice.gov.uk/svn/utils/access/branches/dev/martindix/r133_mask_tools/mask_tools

Installed as a module on raijin

% module use ~access/modules
% module load pythonlib/mask_tools

% python ~access/apps/pythonlib/mask_tools/BOM_station_check.py -h     
usage: BOM_station_check.py [-h] [-d DOMAIN] [-p ANCIL_PATH] [--pdf PDF]

Plot BOM station locations on APS city land-sea masks

optional arguments:
  -h, --help     show this help message and exit
  -d DOMAIN      Domain name used on plots
  -p ANCIL_PATH  Path to ancillary files (if not current directory)
  --pdf PDF      Save output to a PDF file (default is to screen)

Example

% python ~access/apps/pythonlib/mask_tools/BOM_station_check.py -p /short/dp9/wml548/ancil/1.5km/SY -d 'APS2 Sydney' --pdf=sydney.pdf

This creates a multi-page PDF with a map of each station that is not over a land point.

Leaving off the –pdf argument gives output to the screen (closing each one moves to the next).

GA coastline data and station locations are in ~access/data/orography.

penguian commented 8 years ago

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penguian commented 7 years ago

@martin.dix@anu.edu.au _uploaded file lakes_entrance_GA.png (60.3 KiB)_

penguian commented 7 years ago

@martin.dix@anu.edu.au _uploaded file lakes_entrance_SRTM.png (135.9 KiB)_

penguian commented 7 years ago

@martin.dix@anu.edu.au _uploaded file sydney_GA.png (78.4 KiB)_

penguian commented 7 years ago

@martin.dix@anu.edu.au _uploaded file sydney_SRTM.png (200.2 KiB)_

penguian commented 7 years ago

@martin.dix@anu.edu.au _uploaded file wollongong_GA.png (58.0 KiB)_

penguian commented 7 years ago

@martin.dix@anu.edu.au _uploaded file wollongong_SRTM.png (146.1 KiB)_

penguian commented 7 years ago

@martin.dix@anu.edu.au commented

It's also possible to generate a mask by regridding either the GA (250m resolution) or SRTM (90m resolution) orography.

This starts with a mask for the target region to define the grid (just copy the standard one)

module load pythonlib/masktools
python ~access/apps/pythonlib/mask_tools/orog_to_mask.py --source=GA qrparm.mask

This can be run interactively on raijin and creates newmask.nc. This can be used to replace the mask field in qrparm.mask by

module load pythonlib/umfile_utils
python ~access/apps/pythonlib/umfile_utils/um_replace_field.py -v 30 -n newmask.nc -V height qrparm.mask

Use --source=SRTM for the SRTM data.

The GA orography seems consistent with the GA coastline. However both orography and coastline exclude some tidal regions that probably should be treated as ocean (and are so with the IGBP data).

Plots here show the SRTM and GA orography with the GA coastline.

Lake Illawarra and the Gippsland Lakes are both missing and Sydney Harbour only extends to the bridge.

lakes_entrance_IGBP.png lakes_entrance_SRTM.png lakes_entrance_GA.png wollongong_IGBP.png wollongong_SRTM.png wollongong_GA.png sydney_IGBP.png sydney_SRTM.png sydney_GA.png

penguian commented 7 years ago

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penguian commented 7 years ago

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penguian commented 7 years ago

@robin.bowen@bom.gov.au commented

hi Martin

cc to others for their info.

Do you have the relevant parts of this ticket in the wiki docum for ancillaries ?

And question does this need to be documented as specific to city suites ?

cheers

Robin

penguian commented 7 years ago

@martin.dix@anu.edu.au _uploaded file lakes_entrance_IGBP.png (31.0 KiB)_

penguian commented 7 years ago

@martin.dix@anu.edu.au _uploaded file sydney_IGBP.png (50.2 KiB)_

penguian commented 7 years ago

@martin.dix@anu.edu.au _uploaded file wollongong_IGBP.png (33.3 KiB)_

penguian commented 7 years ago

@robin.bowen@bom.gov.au commented

added Gary