While it's true that 'month is not a proper unit of measure',
climatologies do in fact use months, not days, in calculating
mean values. Adhering to udunits/CF in this regard could make
the dates less easily understood.
Regards - Nan
On 9/11/15 1:34 PM, Karl Taylor wrote:
> Dear Ajay,
>
> Since "month" is not a proper unit of measure, convert your times to
> days and use a unit "days since ...".
>
> Also, it is normally a bad idea to have your base time set to a date
> before the switch from Julian to Gregorian calendar. I suggest using a
> base time of "1955-01-01" (i.e., the beginning of your climatological
> period).
>
> I think the cell_methods should be:
> cell_methods="area: mean depth: mean time: mean within years time: mean over years";
>
> The time bounds should be (expressed in date/time format):
>
> climatology_bounds = "1955-01-01", "2012-04-01"
>
> and you can choose your time coordinate value as you think most appropriate, e.g.,
> the middle of the season of the first year of the climatology, or
> the beginning of the first month of the first year of the climatology, or
> the middle of the season of the middle year of the climatology, or
>
> ???
>
>
> Hope someone confirms this, as sometimes I make a mistakes.
>
> Karl
>
>
>
>
> On 9/11/15 9:54 AM, Ajay Krishnan - NOAA Affiliate wrote:
>> Dear CF members,
>>
>> I would like your input on the way climatological stats are being
>> represented in a file that I am working on. I believe that I am not
>> using the time and the climatological_bounds properly:
>>
>> Seasonal SST
>>
>> Average seasonal temperature (Jan-Mar) for 6 decades (1955-2012)
>>
>> dimensions:
>> time=1;
>> nv=2;
>> variables:
>>
>>
>> double time(time);
>> time:climatology="climatology_bounds";
>> time:units="months since 0000-01-01";
>> double climatology_bounds(time,nv);
>>
>>
>> double climatology_bounds(time,nv);
>>
>> climatology_bounds:comment=? This variable defines the bounds of the
>> climatological time period for each time? ;
>>
>> float t_mn(time,lat,lon,depth);
>> t_mn:standard_name: ?sea_water_temperature? ;
>>
>> t_mn:long_name: ?Average of all unflagged interpolated values at each
>> standard depth level for sea_water_temperature in each grid-square
>> which contain at least one measurement.? ;
>>
>> t_mn:cell_methods: ?area: mean depth: mean time: mean? ;
>>
>>
>> data: // time coordinates translated to date/time format
>> time= ?1.5? ;
>>
>> climatology_bounds=?0.0?, ?3.0? ;
>>
>>
>> The CF examples are helpful but my case is different where in I have
>> just 1-time co-ordinate in my file. In the above case, what is the
>> best way to record time and climatology bounds?
>>
>>
>> Thanks,
>>
>> Ajay
>>
>>
--
*******************************************************
* Nan Galbraith (508) 289-2444 *
* Upper Ocean Processes Group Mail Stop 29 *
* Woods Hole Oceanographic Institution *
* Woods Hole, MA 02543 *
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Received on Thu Sep 17 2015 - 07:06:13 BST
