On 3 July 2015 Alison Pamment wrote: 11b. Current status: Under discussion.
smoke_binary_mask (canonical units: 1) 'X_binary_mask has 1 where condition X is met, 0 elsewhere. 1 = smoke present, 0 = smoke absent. If no threshold is supplied, the binary mask is 1 if there is any non-zero amount of smoke.' We would require a definition for the term 'smoke' which is new to standard names. Clearly this is some sort of atmospheric aerosol but is it defined by, for example, size distribution, composition, proximity to fires, any other characteristics? For consistency with existing standard names (see also my comments in 11c and 11d) I suggest we modify the name itself to smoke_ambient_aerosol_particles_binary_mask. Do you agree? -------------------------------------------------------------------- On 13 July Mike Carlomusto replied: Alison - there are existing standard names that define "ambient aerosol particles" as "aerosol particles that have taken up ambient water through hygroscopic growth". This is not the case for smoke aerosol particles. There are however, standard names that use "dry aerosol particles" defined as "aerosol particles without any water uptake". That definition more accurately describes smoke. -------------------------------------------------------------------- Alison Pamment also wrote: The mailing list discussion on the binary mask names focused on including provision to specify a threshold for deciding whether cloud/smoke/dust/aerosol is present in a given scene. It was stated that, for GOES-R, the masks will be assigned a value of 1 if there is any presence of the phenomenon in question, detected by any one of a series of objective tests. However, it was agreed that in order to make the names more generally applicable we should include provision in the definitions for the use of a coordinate variable to specify a non-zero threshold, should it be needed. In the case of the cloud mask, the existing standard name cloud_area_fraction is suitable for such a coordinate variable. For smoke, dust and aerosol, the choice of coordinate variable is less obvious and we may even need to add new standard names to allow for this. Since GOES-R does not actually require a threshold, and currently we have no proposals for suitable coordinate variable names, I propose to add some text to the definitions of the smoke/dust/aerosol masks suggested by Jim Biard (http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2013/056560.html): 'If a threshold is supplied, it may be specified by associating a coordinate variable or scalar coordinate variable with the data variable and giving the coordinate variable a standard name that specifies the quantity used for determining the threshold. The values of the coordinate variable are the threshold values for the corresponding subarrays of the data variable.' This neatly side steps the need to decide coordinate variable names now, but leaves the door open for them to be proposed in the future if another data provider does want to use these names with a non-zero threshold. Would you be happy with this approach? -------------------------------------------------------------------- Mike Carlomusto replied: 1) I agree with the argument for the threshold statement and I would like to submit this modified proposal for a smoke binary mask: smoke_dry_aerosol_particles_binary_mask (canonical units: 1) ' X_binary_mask has 1 where condition X is met, 0 elsewhere. 1 = smoke present, 0 = smoke absent. If no threshold is supplied, the binary mask is 1 if there is any non-zero amount of smoke. A threshold may be specified by associating a coordinate variable or scalar coordinate variable with the data variable and giving the coordinate variable a standard name of smoke_dry_aerosol_particles_area_fraction. The values of the coordinate variable are the threshold values for the corresponding subarrays of the data variable. "Smoke" is an aerosol that is a visible suspension of carbon or other dry aerosol particles in air emitted from a burning substance. Radiative signatures of smoke in an aerosol layer are detected by its scattering and absorption properties which are determined by the index of refraction and the shape and size of the particles, and various other possible measures depending on the characteristics of the sensing instrument or collection method. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Dry aerosol particles" means aerosol particles without any water uptake. ' 2) And a request for a new smoke_dry_aerosol_particles_area_fraction standard name: smoke_dry_aerosol_particles_area_fraction (canonical units: 1) ' X_area_fraction means the fraction of horizontal area occupied by X. "X_area" means the horizontal area occupied by X within the grid cell. "Smoke dry aerosol particles area fraction" is the fraction of the horizontal area that contains dry aerosol particles identified as smoke as determined by the index of refraction and the shape and size of the particles, and various other possible measures depending on the characteristics of the sensing instrument or collection method. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Dry aerosol particles" means aerosol particles without any water uptake. ' Thank you. Michael Carlomusto mcarl...@harris.com<mailto:mcarl...@harris.com> Harris Corp. Government Communications Systems Division (GCSD), GOES-R Ground System Melbourne, FL, USA (321) 309-7905 "This information is only intended for the use of the individual or entity named in this email. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the contents of this information is strictly prohibited. If you have received this email in error, please notify me and delete it immediately." Michael Carlomusto mcarl...@harris.com<mailto:mcarl...@harris.com> Harris Corp. Government Communications Systems Division (GCSD) Melbourne, FL (321) 309-7905
_______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
