Dear CF maintainers,
we would like to propose a few new standard names, a new set of values
for the standard name 'land_cover', and standard name modifiers. The
names are proposals for variables used by the climate change initiative
of the European Space Agency for the essential climate variable 'land
cover' (http://www.esa-landcover-cci.org/). Which additional information
shall we provide to define names (or find existing ones)?
The proposed standard names are 'surface_reflectance',
'probability_of_fire_occurrence', 'probability_of_snow_occurrence',
'probability_of_water_occurrence'. The proposed valids for 'land_cover'
stem from the UN land cover classification system LCCS and from plant
functional types (PFT). The proposed modifiers are 'confidence_level',
'consistency_level', and 'source_flag', Our proposals for definitions
are as follows.
standard name: surface_reflectance
definition: fraction of incident
radiation<http://en.wikipedia.org/wiki/Reflection_%28physics%29>
reflected by a surface, wavelength dependent
unit: none
attribute: wavelength [unit nm]
example:
float sr_2_mean(time, lat, lon) ;
sr_2_mean:long_name = "normalised surface reflectance of
channel 2" ;
sr_2_mean:standard_name = "surface_reflectance" ;
sr_2_mean:wavelength = 442.5 ;
sr_2_mean:valid_min = 0 ;
sr_2_mean:valid_max = 1 ;
sr_2_mean:_FillValue = -999.f ;
standard name: probability_of_fire_occurrence
definition: probability that the observed pixel shows a burned area
unit: none (a value between 0 and 1)
example:
byte fire_probability(time, lat, lon) ;
fire_probability:long_name = "probability of fire" ;
fire_probability:standard_name = "probability_of_fire_occurrence" ;
fire_probability:valid_min = 0 ;
fire_probability:valid_max = 100 ;
fire_probability:_FillValue = -1b ;
fire_probability:scale_factor = 0.01f ;
fire_probability:ancillary_variables = "fire_source
fire_observation_count fire_lcmap_consistency fire_lccond_consistency" ;
standard name: probability_of_snow_occurrence
definition: probability that the observed pixel shows snow or ice
unit: none (a value between 0 and 1)
example:
byte snow_probability(time, lat, lon) ;
snow_probability:long_name = "probability of snow" ;
snow_probability:standard_name = "propability_of_snow_occurrence" ;
snow_probability:valid_min = 0 ;
snow_probability:valid_max = 100 ;
snow_probability:_FillValue = -1b ;
snow_probability:scale_factor = 0.01f ;
snow_probability:ancillary_variables = "snow_source
snow_observation_count snow_lcmap_consistency snow_lccond_consistency" ;
standard name: probability_of_water_occurrence
definition: probability that the observed pixel shows water
unit: none (a value between 0 and 1)
example:
byte water_probability(time, lat, lon) ;
water_probability:long_name = "probability of water" ;
water_probability:standard_name =
"propability_of_water_occurrence" ;
water_probability:valid_min = 0 ;
water_probability:valid_max = 100 ;
water_probability:_FillValue = -1b ;
water_probability:scale_factor = 0.01f ;
water_probability:ancillary_variables = "water_source
water_observation_count water_lcmap_consistency water_lccond_consistency" ;
For the existing standard name land_cover which is a synonym of
area_type we propose to allow for external vocabularies as valids. We
propose to represent them as enumeration with flag_values and
flag_meanings. (The current CF approach is to allow for string values
with the valids listed in a CF area_type table. We have read the
discussion on area_type e.g. in
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2011/022389.html and
we do not think that the use of area_type table is appropriate for names
already standardised elsewhere, and in our case we furthermore need
valids from different classification schemes) There are in fact two
classifications used in the LC CCI project. The first list is a subset
of LCCS classifier combinations. The other list of valids from plant
functional types (PFT) is listed in the second example below.
valids for land_cover: no_data cropland_rainfed cropland_irrigated
mosaic_cropland mosaic_natural_vegetation
tree_broadleaved_evergreen_closed_to_open
tree_broadleaved_deciduous_closed tree_broadleaved_deciduous_open
tree_needleleaved_evergreen_closed tree_needleleaved_evergreen_open
tree_needleleaved_deciduous_closed tree_needleleaved_deciduous_open
tree_mixed mosaic_tree_and_shrub mosaic_herbaceous shrubland grassland
sparse_vegetation tree_cover_flooded_fresh_or_brakish_water
tree_cover_flooded_saline_water shrub_or_herbaceous_cover_flooded urban
bare_areas water snow_and_ice
definition: composition of classifiers from LCCS (see Di Gregorio A.,
2005, UN Land Cover Classification System (LCCS) -- Classification
concepts and user manual for Software version 2. Available at:
http://www.fao.org/docrep/003/X0596E/x0596e01f.htm#p1153_114656)
unit: none (flag_values and flag_meanings)
attribute: vocabulary (proposal to refer to a vocabulary instead of
re-defining in CF)
examples:
byte lccs_class(lat, lon) ;
lccs_class:long_name = "Land cover class defined in LCCS" ;
lccs_class:standard_name = "land_cover" ;
lccs_class:flag_values = 0b, 10b, 20b, 30b, 40b, 50b, 60b, 70b,
80b, 90b, 100b, 110b, 120b, 130b, 140b, 150b, 160b, 170b, 180b, 190b,
200b, 210b, 220b, 230b, 240b ;
lccs_class:flag_meanings = "no_data cropland_rainfed
cropland_irrigated mosaic_cropland mosaic_natural_vegetation
tree_broadleaved_evergreen_closed_to_open
tree_broadleaved_deciduous_closed tree_broadleaved_deciduous_open
tree_needleleaved_evergreen_closed tree_needleleaved_evergreen_open
tree_needleleaved_deciduous_closed tree_needleleaved_deciduous_open
tree_mixed mosaic_tree_and_shrub mosaic_herbaceous shrubland grassland
sparse_vegetation tree_cover_flooded_fresh_or_brakish_water
tree_cover_flooded_saline_water shrub_or_herbaceous_cover_flooded urban
bare_areas water snow_and_ice" ;
lccs_class:vocabulary = "UN-LCCS 2005" ;
lccs_class:valid_min = 1 ;
lccs_class:valid_max = 240 ;
lccs_class:_FillValue = 0b ;
byte pft_class(lat, lon) ;
pft_class:long_name = "Land cover class defined in PFT" ;
pft_class:standard_name = "land_cover" ;
pft_class:flag_values = 1b, 2b, 3b, 4b, 5b, 6b, 7b, 8b, 9b,
10b, 11b ;
pft_class:flag_meanings = "broadleaved_evergreen
broadleaved_deciduous needleleaved_evergreen needleleaved_deciduous
shrubs natural_grass managed_grass wetland bare urban water" ;
pft_class:vocabulary = "LC-CCI PFT 2011" ;
pft_class:valid_min = 1 ;
pft_class:valid_max = 11 ;
pft_class:_FillValue = 0b ;
Finally, instead of adding new standard names we would like to ask
whether it would be appropriate to extend the set of standard name
modifiers. Our candidates are
standard name modifier: confidence_level
definition: applied to some discrete variable, denotes the probability that the
assignment of the value to the variable is correct
example:
byte algorithmic_confidence_level(lat, lon) ;
algorithmic_confidence_level:long_name = "LC map confidence
level based on algorithm performance" ;
algorithmic_confidence_level:standard_name = "land_cover
confidence_level" ;
algorithmic_confidence_level:valid_min = 0 ;
algorithmic_confidence_level:valid_max = 100 ;
algorithmic_confidence_level:_FillValue = -1b ;
algorithmic_confidence_level:scale_factor = 0.01f ;
standard name modifier: consistence_level
definition: applied to some variable, with relation to some other
variable, denotes level of consistency within the dataset
example:
byte fire_lcmap_consistency(time, lat, lon) ;
fire_lcmap_consistency:long_name = "consistency of fire
condition with LC map" ;
fire_lcmap_consistency:standard_name =
"probability_of_fire_occurrence consistency_level" ;
fire_lcmap_consistency:valid_min = 0 ;
fire_lcmap_consistency:valid_max = 100 ;
fire_lcmap_consistency:_FillValue = -1b ;
fire_lcmap_consistency:scale_factor = 0.01f ;
more examples:
propability_of_snow_occurrence consistency_level
propability_of_water_occurrence consistency_level
normalized_difference_vegetation_index consistency_level
standard name modifier: source_flag
definition: applied to some variable, denotes information source used to
derive the value
example:
byte fire_source(time, lat, lon) ;
fire_source:long_name = "source of fire condition" ;
fire_source:standard_name = "probability_of_fire_occurrence
source_flag" ;
fire_source:flag_values = 1b, 2b, 3b ;
fire_source:flag_meanings = "ATSR_World_Fire_Atlas
MODIS_Burned_Area_Product CCI_Fire_Product" ;
fire_source:valid_min = 1 ;
fire_source:valid_max = 3 ;
fire_source:_FillValue = 0b ;
more examples:
propability_of_snow_occurrence source_flag
propability_of_water_occurrence source_flag
normalized_difference_vegetation_index source_flag
Best regards,
Martin Boettcher
for the ESA Land Cover CCI project
--
Dr. Martin Boettcher
Brockmann Consult GmbH
Max-Planck-Straße 2
D-21502 Geesthacht
Tel: +49 (0)4152 889 315
Fax: +49 (0)4152 889 333
www.brockmann-consult.de
Amtsgericht Geesthacht HRB 698
Geschäftsführer Dr. Carsten Brockmann
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