[NARCCAP-discuss] time discrepancy

Shane Brennan sbren006 at odu.edu
Fri Aug 24 09:13:44 MDT 2012


Hi,

I am writing a C# program to parse and manipulate NARCCAP data. I
wanted to verify the missing data values to make sure I was handling
them correctly so I checked out:

http://www.narccap.ucar.edu/data/missing/CRCM_ccsm-current_table3_missing.txt

to find where I could look for missing values. In the URL above, it
states that evps in the file evps_CRCM_ccsm_1996010103.nc has missing
values for 1999-12-01 03:00 through 2000-01-01 00:00.

I would expect the time series for the entire file to run from
1996-01-01 03:00 to 2000-01-01 00:00. However, when I parse this file
with my program and then use excel to calculate the times from
1/1/1968 (the start date returned from ncdump for this file), I get a
time series that runs from 12/25/1995 03:00 to 12/24/1999 00:00. In
this file, my missing values run from 11/23/1999 03:00 to 12/24/1999
00:00.

Naturally, I became concerned that I had a bug in my program. However,
when I use nc2text.exe using the instructions detailed in the ASCII
HowTo, I get the same results.

In Excel I calculate the offset date by entering 1/1/1968 into a cell,
and calculating a new field as that cell value added to each time
value (for example, if the cell for 1/1/1968 is G1, then my formula
for the first cell is "=$G$1 + a1". I then copy this formula all the
way down).

Does anyone know what is going on? Perhaps there is some issue with
leap years or DST?

Shane


More information about the narccap-discuss mailing list