[ncl-talk] Creating Time Series Plots with Joined Arrays

Wed Apr 4 06:20:30 MDT 2018

Thanks for the guidance and clarification Adam. I greatly appreciate it. Have a nice day.

Regards,

-Stuart

From: Adam Phillips <asphilli at ucar.edu> 
Sent: Tuesday, April 3, 2018 7:11 PM
To: Smith, Stuart <smit1770 at purdue.edu>
Cc: Ncl-talk <ncl-talk at ucar.edu>
Subject: Re: [ncl-talk] Creating Time Series Plots with Joined Arrays

Hi Stuart,

I think the main issue is that you are joining the files together (you have to as they do not have a time dimension), and the joined time coordinate is not getting converted to be consistent amongst the timesteps.

Each of your two sample files has a time array with a different units attribute, with time set to 0 for each.

file 1:

Variable: time (file variable)

Type: float

Total Size: 8 bytes

            2 values

Number of Dimensions: 1

Dimensions and sizes: [time | 2]

Coordinates: 

            time: [ 0..80640]

Number Of Attributes: 5

  units : minutes since 2009-01-20 00:00:00

  long_name :  time

  time_increment :       86400

  begin_date :   20090120

  begin_time :  000000

file 2:

Variable: time (file variable)

Type: float

Total Size: 8 bytes

            2 values

Number of Dimensions: 1

Dimensions and sizes: [time | 2]

Coordinates: 

            time: [ 0..80640]

Number Of Attributes: 5

  units : minutes since 2009-03-17 00:00:00

  long_name :  time

  time_increment :       86400

  begin_date :   20090317

  begin_time :  000000

By default, addfiles will concatenate and adjust the time variable appropriately.

b = addfiles(fils,"r")

time = b[:]->time

print(time)

Variable: time

Type: float

Total Size: 8 bytes

            2 values

Number of Dimensions: 1

Dimensions and sizes: [time | 2]

Coordinates: 

            time: [ 0..80640]

Number Of Attributes: 5

  units : minutes since 2009-01-20 00:00:00

  long_name :  time

  time_increment :       86400

  begin_date :   20090120

  begin_time :  000000

(0)        0

(1)        80640

Thus, I think the solution is to continue to join your data arrays through addfiles, but also concatenate the time variable through a separate call to addfiles:

b = addfiles(fils,"r")

time = b[:]->time

a = addfiles(fils,"r")

ListSetType (a, "join")

data = a[:]->vic_lake_area_inst

data at time=a[:]->time

data!0 = "time"

data&time = time   ; assign time coordinate variable

; then, farther down your script change this:

date       = cd_calendar(a[:]->time,0)

to this:

date       = cd_calendar(data&time,0)

That should do it. If you have any further questions please respond to the ncl-talk email list.

Adam

On Tue, Apr 3, 2018 at 4:00 PM, Smith, Stuart <smit1770 at purdue.edu <mailto:smit1770 at purdue.edu> > wrote:

Hello,

I am trying to augment my code to improve the display of figures. My goal is to plot variables during specific months. The attached code is currently setup to read in all of the netCDF files from a specific year, join the files, and then plot a variable of interest. 

When working to plot specific months, I added the “cd_calendar” function to change the values to calendar time. The output I get is listed below, which is also the same as when I print(data at time). This issue is caused by joining the arrays from the list of files.

Does anyone have any recommendations to change the array to the correct time format? I have attached sample data and the code. Thank you for your time.

(362,0) 2009

(362,1)  1

(362,2)  1

(362,3)  0

(362,4)  0

(362,5)  0

(363,0) 2009

(363,1)  1

(363,2)  1

(363,3)  0

(363,4)  0

(363,5)  0

(364,0) 2009

(364,1)  1

(364,2)  1

(364,3)  0

(364,4)  0

(364,5)  0

Regards,

-Stuart 

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-- 

Adam Phillips 

Associate Scientist,  Climate and Global Dynamics Laboratory, NCAR

www.cgd.ucar.edu/staff/asphilli/ <http://www.cgd.ucar.edu/staff/asphilli/>    303-497-1726 

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