Hi Jim,
Actually, the latitude, longitude, and z values are not sampled at different
rates (I showed them as such for an extreme example, and in some decimation
schemes they end up being asynchronous), but in reality the science data are
collected asynchronously from each other and the coordinate data.
I can't find where the CF standard specifies that a trajectory must have a
single time dimension (perhaps I've missed it). If it does, and this is a
collection of time series, can a collection of time series be represented in a
CF-compliant file? If so how would one indicate that lat, lon, and z are the
coordinates through which O3 and NO3 vary?
If it helps, one could imagine the following somewhat simpler CDL, in which
coordinates are time-synchronized but scientific measurements are not:
dimensions:
time_coords = 435;
time_O3 = 335;
time_NO3 = 5357;
variables:
double time_coords(time_coords) ;
time_coords:standard_name = "time";
time_coords:long_name = "time_coords" ;
time_coords:units = "days since 1970-01-01 00:00:00" ;
float lon(time_coords) ;
lon:standard_name = "longitude";
lon:long_name = "longitude" ;
lon:units = "degrees_east" ;
float lat(time_coords) ;
lat:standard_name = "latitude";
lat:long_name = "latitude" ;
lat:units = "degrees_north" ;
float z(time_coords) ;
z:standard_name = “altitude”;
z:long_name = "height above mean sea level" ;
z:units = "km" ;
z:positive = "up" ;
z:axis = "Z" ;
double time_O3(time_O3) ;
time_O3:standard_name = "time";
time_O3:long_name = "time_O3" ;
time_O3:units = "days since 1970-01-01 00:00:00" ;
float O3(time_O3) ;
O3:standard_name = “mass_fraction_of_ozone_in_air”;
O3:long_name = "ozone concentration" ;
O3:units = "1e-9" ;
O3:coordinates = "time_O3 lon lat z" ;
double time_NO3(time_NO3) ;
time_NO3:standard_name = "time";
time_NO3:long_name = "time_NO3" ;
time_NO3:units = "days since 1970-01-01 00:00:00" ;
float O3(time_NO3) ;
NO3:standard_name = “mass_fraction_of_nitrate_radical_in_air”;
NO3:long_name = "NO3 concentration" ;
NO3:units = "1e-9" ;
NO3:coordinates = "time_NO3 lon lat z" ;
attributes:
:featureType = "????";
Thanks,
Mike Godin
Lead Engineer,
IntuAware
http://intuaware.com
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