Hi Alison,
The primary and secondary land definition looks good. The urban definition
seems a bit excessive for these purposes. I suggest simplifying to:
Urban land is comprised of areas where much of the land is covered by
structures. Included in this category are cities, towns, and villages.
The reference is still suitable.
Dave
On Wed, Jan 25, 2017 at 9:48 AM, <alison.pamment at stfc.ac.uk> wrote:
> Dear David and Lena,
>
> I will shortly be making an update to the CF area_types table and I will
> be adding the changes we agreed previously: http://mailman.cgd.ucar.edu/pi
> permail/cf-metadata/2016/059111.html. I have found what appears to be a
> reasonable definition for 'urban' which I have quoted straight from the
> given reference. Is this OK or can you point me to a more recent reference,
> perhaps one with a doi?
>
> primary_and_secondary_land
> ' "Primary and secondary land" is all vegetated land that is not in active
> use as cropland or pastureland, including forests, grasslands, bare ground
> and vegetated wetlands. "Primary land" is land that has never been
> subjected to human disturbance. "Secondary land" is land that has undergone
> human disturbance and has either subsequently been abandoned or is
> currently being managed for human use (e.g., wood harvest). Reference:
> Hurtt et al. (2011), Climatic Change, 109 - 117, Harmonization of land-use
> scenarios for the period 1500-2100: 600 years of global gridded annual
> land-use transitions, wood harvest, and resulting secondary lands, doi:
> 10.1007/s10584-011-0153-2. "Primary and secondary land" refers to a land
> use, rather than to specific categories of vegetation, and is distinct from
> the area types for primary and secondary trees.'
>
> pastures
> 'Pastures are assumed to be anthropogenic in origin. They include
> anthropogenically managed pastureland and rangeland.'
>
> urban
> 'Urban or Built-up Land is comprised of areas of intensive use with much
> of the land covered by structures. Included in this category are cities,
> towns, villages, strip developments along highways, transportation, power,
> and communications facilities, and areas such as those occupied by mills,
> shopping centers, industrial and commercial complexes, and institutions
> that may, in some instances, be isolated from urban areas. Reference:
> Anderson, J.R, E. E. Hardy, J. T. Roach and R. E. Witmer (1976), A Land Use
> And Land Cover Classification System For Use With Remote Sensor Data,
> Appendix C Land Use Defintions, Geological Survey Professional Paper 964, A
> revision of the land use classification system as presented in U.S.
> Geological Survey Circular 671, https://www.usbr.gov/lc/socal/
> reports/SMappend_C.pdf.'
>
> Best wishes,
> Alison
>
> ------
> Alison Pamment Tel: +44
> 1235 778065
> Centre for Environmental Data Analysis Email:
> alison.pamment at stfc.ac.uk
> STFC Rutherford Appleton Laboratory
> R25, 2.22
> Harwell Campus, Didcot, OX11 0QX, U.K.
>
>
>
>
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