Dear Etienne, Jonathan, and all,
For CMIP5, I've ncdumped below some of the information in the Plant
Functional Type Grid Fraction". We asked the groups to include a
precise description of the plant function type in a variable named
"type_description", but this is not standardized. Note that the
coordinate "type" is a simple index and again is not standardized across
models.
regards,
Karl
ncdump landCoverFrac_Lmon_MPI-ESM-LR_1pctCO2_r1i1p1_199001-199912.nc | more
netcdf landCoverFrac_Lmon_MPI-ESM-LR_1pctCO2_r1i1p1_199001-199912 {
dimensions:
time = UNLIMITED ; // (120 currently)
type = 13 ;
lat = 96 ;
lon = 192 ;
bnds = 2 ;
strlen = 34 ;
variables:
double time(time) ;
time:bounds = "time_bnds" ;
time:units = "days since 1850-1-1 00:00:00" ;
time:calendar = "proleptic_gregorian" ;
time:axis = "T" ;
time:long_name = "time" ;
time:standard_name = "time" ;
double time_bnds(time, bnds) ;
char type_description(type, strlen) ;
type_description:long_name = "plant functional type" ;
type_description:standard_name = "area_type" ;
double lat(lat) ;
lat:bounds = "lat_bnds" ;
lat:units = "degrees_north" ;
lat:axis = "Y" ;
lat:long_name = "latitude" ;
lat:standard_name = "latitude" ;
double lat_bnds(lat, bnds) ;
double lon(lon) ;
lon:bounds = "lon_bnds" ;
lon:units = "degrees_east" ;
lon:axis = "X" ;
lon:long_name = "longitude" ;
lon:standard_name = "longitude" ;
double lon_bnds(lon, bnds) ;
float landCoverFrac(time, type, lat, lon) ;
landCoverFrac:standard_name = "area_fraction" ;
landCoverFrac:long_name = "Plant Functional Type Grid
Fraction" ;
landCoverFrac:comment = "The categories may differ from
model to model, depending on their PFT definitions. This may include
natural PFTs, anthropogenic PFTs, bare soil, lakes, urban areas, etc.
Sum of all should equal the fraction of the grid-cell
that is land." ;
landCoverFrac:units = "%" ;
landCoverFrac:cell_methods = "time: mean" ;
landCoverFrac:cell_measures = "area: areacella" ;
landCoverFrac:history = "2011-06-01T05:07:12Z altered
by CMOR: replaced missing value flag (1e+22) with standard missing value
(1e+20)." ;
landCoverFrac:missing_value = 1.e+20f ;
landCoverFrac:_FillValue = 1.e+20f ;
landCoverFrac:associated_files = "baseURL:
http://cmip-pcmdi.llnl.gov/CMIP5/dataLocation gridspecFile:
gridspec_land_fx_MPI-ESM-LR_1pctCO2_r0i0p0.nc areacella:
areacella_fx_MPI-ESM-LR_1pctCO2_r0i0p0.nc" ;
landCoverFrac:coordinates = "type_description" ;
// global attributes:
:institution = "Max Planck Institute for Meteorology" ;
:institute_id = "MPI-M" ;
:experiment_id = "1pctCO2" ;
:source = "MPI-ESM-LR 2011; URL:
http://svn.zmaw.de/svn/cosmos/branches/releases/mpi-esm-cmip5/src/mod;
atmosphere: ECHAM6 (REV: 4571), T63L47; land: JSBACH (REV: 4571); ocean:
MPIOM (REV: 4571), GR15L40; sea ice: 4571; marine bgc: HAMOCC (REV: 4571);"
:model_id = "MPI-ESM-LR" ;
:forcing = "N/A" ;
:parent_experiment_id = "piControl" ;
:parent_experiment_rip = "r1i1p1" ;
:branch_time = 10957. ;
:contact = "cmip5-mpi-esm at dkrz.de" ;
:history = "Model raw output postprocessing with
modelling environment (IMDI) at DKRZ: URL:
http://svn-mad.zmaw.de/svn/mad/Model/IMDI/trunk, REV: 3208
2011-06-01T05:07:12Z CMOR rewrote data to comply with CF standards and
CMIP5 requirements." ;
:references = "ECHAM6: n/a; JSBACH: Raddatz et al.,
2007. Will the tropical land biosphere dominate the climate-carbon cycle
feedback during the twenty first century? Climate Dynamics, 29, 565-574,
doi 10.1007/s00382-007-0247-8; MPIOM: Marsland et al.,
2003. The Max-Planck-Institute global ocean/sea ice model with
orthogonal curvilinear coordinates. Ocean Modelling, 5, 91-127; HAMOCC:
http://www.mpimet.mpg.de/fileadmin/models/MPIOM/HAMOCC5.1_TECHNICAL_REPORT.pdf;"
;
:initialization_method = 1 ;
:physics_version = 1 ;
:tracking_id = "91871851-f604-400d-a473-10ebc3a98638" ;
:product = "output" ;
:experiment = "1 percent per year CO2" ;
:frequency = "mon" ;
:creation_date = "2011-06-01T05:07:12Z" ;
:Conventions = "CF-1.4" ;
:project_id = "CMIP5" ;
:table_id = "Table Lmon (27 April 2011)
c4244dce0826a43bb0b259f293e2f742" ;
:title = "MPI-ESM-LR model output prepared for CMIP5 1
percent per year CO2" ;
:parent_experiment = "pre-industrial control" ;
:modeling_realm = "land" ;
:realization = 1 ;
:cmor_version = "2.5.9" ;
data:
.
.
.
.
type_description =
"glacier ",
"tropical broadleaf evergreen trees",
"tropical broadleaf deciduous trees",
"extra-tropical evergreen trees ",
"extra-tropical deciduous trees ",
"raingreen shrubs ",
"deciduous shrubs ",
"C3grass ",
"C4grass ",
"C3 pasture ",
"C4 pasture ",
"C3crops ",
"C4crops " ;
.
.
.
.
On 6/4/12 10:17 AM, Jonathan Gregory wrote:
> Dear Etienne
>
> I think the structure you have adopted for the data is fine.
>
>> double pft(pft) ;
>> pft:long_name = "plant functional type" ;
>> pft:units = "none" ;
>>
>> double npp(time, pft, latitude, longitude) ;
>> npp:long_name = "npp of carbon for each pft" ;
>> npp:units = "kg m-2 year-1" ;
> The specific problem you raise is concerned with the axis attribute. That
> attribute is really intended for identifying spatiotemporal coordinates;
> although it may be convenient, it is redundant because they can also be
> identified in other ways. It has not been extended for non-spatiotemporal
> axes like pft. In your CDL, the pft axis is identified by its long_name.
> To make this more reliable, you might want to use a standard_name for this
> pft coordinate variable. There isn't such a standard_name at present, but
> area_type is often vegetation type in practice, so you could perhaps use
> that. We could standardise new area_types by proposals to this email list.
>
> Also, there is the new proposal, which I expect will go into the
> standard_name table, for UN/FAO land cover types, which in many cases are
> also vegetation types.
> See http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2012/033507.html
>
> The quantities identified by these standard_names are string-valued, whereas
> you expect a numeric pft. However, a string-valued one could be encoded as a
> number by using the flag_values and flag_meanings attributes.
>
> There is an existing standard name for NPP as well viz
> net_primary_productivity_of_carbon (kg m-2 s-1)
>
> Best wishes
>
> Jonathan
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
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Received on Mon Jun 04 2012 - 12:08:36 BST
