[gradsusr] 回复： Changing TDEF Interval Does Not Work

[weather.man]

Hi Justin
I hope you can read chinese.
你的理解是错的，你说以前这样做是可以的，但我觉得结果肯定有问题。
control file 本来就是数据和grads之间的桥梁，它必须正确的描述资料的排列、分辨率、起始经纬度、时间的间隔等等，这样才能让grads知道它要操作的数据是什么样的。所以你的资料时间间隔本来就是1mo的话，通过强制改变control file 里的时间间隔是没有用的，除非你的资料时间间隔改变，否则只会让grads得到一个错误的时间。
如果你想使用间隔一个月时间的资料来计算，最好的办法是在 .gs 脚本里面实现


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发件人：Justin Hicks <jhicks2014 at gmail.com>
发送时间：2018年7月6日(星期五) 04:48
收件人：GrADS Users Forum <gradsusr at gradsusr.org>
主　题：[gradsusr] Changing TDEF Interval Does Not Work

GrADS community,

I am running into a strange issue concerning the TDEF entry in my dummy control file. I am trying to change the TDEF interval entry from '1dy' to '1mo', as I need the first day of every month for computational purposes. However, when I change it to an interval of 1 month and open up the file / display the variable, the interval is correct, but the data displays as if the interval is still daily. For example, if I set the time environment from t=1 to t=2, the interval that shows up is 00Z01jan2000 to 00Z01feb2000, but the actual data that displays is from 00Z01jan2000 to 00Z02jan2000; this is pretty clear because I am plotting total precipitable water, and there isn't much variation between the two time steps. I've also compared this with what should be showing up for 00Z01feb2000. I'm not sure what's going on, as I was able to get this working with another dataset.

Here is the output of ncdump -h:

netcdf NVAP-M_2000-2009.time.grid.rmp.fill.dummy.USE {
dimensions:
        lon = 360 ;
        lat = 180 ;
        time = UNLIMITED ; // (3653 currently)
variables:
        double lon(lon) ;
                lon:standard_name = "longitude" ;
                lon:long_name = "longitude" ;
                lon:units = "degrees_east" ;
                lon:axis = "X" ;
        double lat(lat) ;
                lat:standard_name = "latitude" ;
                lat:long_name = "latitude" ;
                lat:units = "degrees_north" ;
                lat:axis = "Y" ;
        double time(time) ;
                time:standard_name = "time" ;
                time:long_name = "Time" ;
                time:units = "minutes since 2000-1-1 00:00:00" ;
                time:calendar = "standard" ;
                time:axis = "T" ;
        double tpw(time, lat, lon) ;
                tpw:_FillValue = -999000000. ;
                tpw:missing_value = -999000000. ;

// global attributes:
                :CDI = "Climate Data Interface version 1.7.2 (http://mpimet.mpg.de/cdi)" ;
                :Conventions = "CF-1.4" ;
                :history = "Thu Jul 05 16:42:12 2018: cdo remapcon2,/home/jhicks/Downloads/mygridIN.txt NVAP-M_2000-2009.time.grid.rmp.fill.dummy.nc NVAP-M_2000-2009.time.grid.rmp.fill.dummy.USE.nc" ;
                :CDO = "Climate Data Operators version 1.7.2 (http://mpimet.mpg.de/cdo)" ;
}



And here is the dummy control file:

dset /data2/NVAP-M/NVAP-M_2000-2009.time.grid.rmp.fill.dummy.USE.nc
title NASA Water Vapor Project - MEaSUREs Dataset
undef -9999
dtype netcdf
xdef 360 linear -179.5 1
ydef 180 linear -89.5 1
zdef 1 linear 0 1
tdef 120 linear 00Z01JAN2000 1mo
vars 1
tpw=>tpw  0  t,y,x  NVAP-M Climate Total Column Water Vapor
endvars


Thanks,

-Justin




-- 
Justin Hicks
Undergraduate
Atmospheric Sciences Major
GIS Minor
University of Maryland-College Park
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