alexjt@umich_edu
New Member
I am working with CESM2 Large Ensemble data at /campaign/cgd/cesm/CESM2-LE/atm/proc/tseries/ and would like some clarification regarding six-hourly and daily data. I have searched other documentation but have been unable to find answers to these specific questions.
For six-hourly data…
Question #1
Are T, Q, U, V, and Z3 output variables instantaneous or time-averaged? If they are instantaneous, what does the time_bnds variable tell us - is the instantaneous value taken at the first or second time_bnd?
Question #2
When concatenating all of the files together (1850-2100) there are 366,462 six-hourly times. This is two more than there should be given a 365 day year. By investigating the “time_bnds” variable, I found two times that look like extra data:
1. First time index in file 1850010100-1859123100, which has time_bnds of “1850-01-01 00hrs” to “1850-01-01 00hrs”. This data point is very similar, but not identical, to the second time index in this file, which has time_bnds of “1850-01-01 00hrs” to “1850-01-01 06hrs”.
2. First time index in file 2015010100-2024123100, which has time_bnds of “2015-01-01 00hrs” to “2015-01-01 00hrs”. This data point is very similar, but not identical, to the last time index in file 2010010100-2014123100, which has time_bnds of “2014-12-31 18hrs” to “2015-01-01 00hrs”.
Are these the two extra times? What are these values if their time_bnds do not span a six-hourly period? If constructing a six-hourly time series between 1850-01-01 00:00:00 and 2100-12-31 24:00:00, should these two values be removed?
For daily data…
Question #1
I assume that T, Q, U, V, and Z3 are all time-averages. Is this assumption correct?
Question #2
When concatenating all of the files together (1850-2100) there are 91617 daily times. This is also two more than there should be given a 365 day year. Similarly to the six-hourly files, I found by investigating “time_bnds” that there appeared to be two extra times at the beginning of file 18500101-18591231 and file 20150101-20241231.
Likewise, are these extra times that should be removed if creating a time series of daily data from 1850-01-01 to 2100-12-31?
For six-hourly data…
Question #1
Are T, Q, U, V, and Z3 output variables instantaneous or time-averaged? If they are instantaneous, what does the time_bnds variable tell us - is the instantaneous value taken at the first or second time_bnd?
Question #2
When concatenating all of the files together (1850-2100) there are 366,462 six-hourly times. This is two more than there should be given a 365 day year. By investigating the “time_bnds” variable, I found two times that look like extra data:
1. First time index in file 1850010100-1859123100, which has time_bnds of “1850-01-01 00hrs” to “1850-01-01 00hrs”. This data point is very similar, but not identical, to the second time index in this file, which has time_bnds of “1850-01-01 00hrs” to “1850-01-01 06hrs”.
2. First time index in file 2015010100-2024123100, which has time_bnds of “2015-01-01 00hrs” to “2015-01-01 00hrs”. This data point is very similar, but not identical, to the last time index in file 2010010100-2014123100, which has time_bnds of “2014-12-31 18hrs” to “2015-01-01 00hrs”.
Are these the two extra times? What are these values if their time_bnds do not span a six-hourly period? If constructing a six-hourly time series between 1850-01-01 00:00:00 and 2100-12-31 24:00:00, should these two values be removed?
For daily data…
Question #1
I assume that T, Q, U, V, and Z3 are all time-averages. Is this assumption correct?
Question #2
When concatenating all of the files together (1850-2100) there are 91617 daily times. This is also two more than there should be given a 365 day year. Similarly to the six-hourly files, I found by investigating “time_bnds” that there appeared to be two extra times at the beginning of file 18500101-18591231 and file 20150101-20241231.
Likewise, are these extra times that should be removed if creating a time series of daily data from 1850-01-01 to 2100-12-31?