Dear Martin
> "cloud_mask"
> Description: A variable with the standard name of cloud_mask contains
> strings which indicate whether it is cloudy or not, also classes like
> partly_cloudy is allowed. These strings have not been standardised.
I too feel rather doubtful about unstandardised text descriptions of cloud
fraction, or other types of area fraction. To me it would seem preferable
to use cloud_area_fraction and assign it nominal numerical values. Are there
objective criteria for choosing a text description?
> "cloud_type"
> Description: A variable with the standard name of cloud_type contains
> strings which indicate the type of cloud e.g. low_level_cloud or
> thin_cirrus.
There are three new names which I believe should be added to the standard
name table, since they were agreed in June (see email postings with the
title "Standard_name for cloud-cover by phenomenon":
> low_type_cloud_area_fraction
> medium_type_cloud_area_fraction
> high_type_cloud_area_fraction
This is somewhat related. If more specific cloud types are required, it would
be good to use existing standard terminology. For describing cloud thickness,
numerical values would be preferable, I would suggest.
> "probability_of_precipitation_in_an_intensity_interval"
> Description: "probability_of_X" means the chance that X is true or of at
> least one occurrence of X.
> For probability_of_precipitation_in_an_intensity_interval, this means
> the chance (in percent) that the precipitation intensity is in the
> defined interval. The interval (from x mm/h to y mm/h) should be
> described in attribute description. Usually two or more variables of
> this type are combined, for adjacent intervals.
> Units: 1
Following the guidelines for constructions of standard_names
http://cf-pcmdi.llnl.gov/documents/cf-standard-names/guidelines
I think this quantity would be called
probability_distribution_of_precipitation_rate
and the interval would be recorded in the bounds of a size-1 or scalar
coordinate variable with standard_name of precipitation_rate. In fact this
would also be a new standard_name, but it would be an obvious proposal to
make, since the following are already in the standard_name table:
convective_precipitation_rate:m s-1
lwe_convective_precipitation_rate:m s-1
lwe_large_scale_precipitation_rate:m s-1
lwe_precipitation_rate:m s-1
m s-1 is the canonical unit, but mm h-1 is physically equivalent.
Best wishes
Jonathan
Received on Fri Sep 28 2012 - 15:24:22 BST
