Zeu or ZLEE data download via Direct Access?

Use this Forum to find information on, or ask a question about, NASA Earth Science data.
Post Reply
aleitner
Posts: 8
Joined: Fri Apr 07, 2017 7:16 am America/New_York
Answers: 0

Zeu or ZLEE data download via Direct Access?

by aleitner » Sat Apr 08, 2017 3:26 pm America/New_York

Hello Everyone,
I very new to using the Ocean Color data products and am trying to find a Monthly data product for euphotic layer depth. I have read that Zeu is no longer a standard product but also that the product would be posted in Jan 2017. Is there any progress on this?

From reading other forum posts it seems my only other option would be to use SeaDAS to derive Zeu using the Lee algorithm from the level 1A MODIS AQUA data. I currently cannot get the luts aqua to install for SeaDAS despite having the correct Python version and having restarted my computer as suggested by responses to other posts on the subject. The error I get is a network connection error, which persists despite a solid ethernet connection. Any suggestions as to how to fix this install error would be greatly appreciated.

In the meantime, to circumvent this frustrating roadblock I decided to use the file search for *MO_ZLEE* to see if there were still accessible files for this data product, and I actually got 176 results for example:
A20163362016366.L3b_MO_ZLEE.nc  2017-01-17 05:01:00  89106.42 (kB)  View input files
Is this a product that I could use? Could someone explain the file naming convention to me (apologies for my very basic question). A2016 is clearly the year L3b is level 3 binned, MO=monthly; however what are the rest of the numbers in the beginning of the name A20163362016366? There are 11 files for 2016 for example, and I don't understand what 336 refers to. I have looked at this nc file, and clearly it is a piece of the 2016 data:
                time_coverage_start = "2016-12-01T00:35:09.000Z" ;
    :time_coverage_end = "2017-01-01T02:10:09.000Z" ;
    :northernmost_latitude = 47.8125f ;
    :southernmost_latitude = -78.60416f ;
    :easternmost_longitude = 179.9792f ;
    :westernmost_longitude = -179.9792f ;
I was also confused to see that although the name of the file is ZLEE the units are in angstroms. I assume this means that further processing would be required to get to a euphotic layer depth?

Any help would be greatly appreciated, I am a graduate student with no satellite oceanographers to consult for help on my project at my home institution.

Filters:

OB ODPS - towens
Subject Matter Expert
Subject Matter Expert
Posts: 395
Joined: Fri Feb 05, 2021 9:17 am America/New_York
Answers: 0
Been thanked: 5 times

Zeu or ZLEE data download via Direct Access?

by OB ODPS - towens » Mon Apr 10, 2017 8:34 am America/New_York

I can answer some of  your questions.
The naming convention is:
A=Mission MODIS on Aqua
2016=starting year
336 = Starting day of year
2016 = ending year
366 = ending day of year

ZLEE is given in meters. angstrom is a unit-less product in the input Level-2 file, not the units of the output product.

Tommy

OB.DAAC - SeanBailey
User Services
User Services
Posts: 1485
Joined: Wed Sep 18, 2019 6:15 pm America/New_York
Answers: 1
Been thanked: 5 times

Zeu or ZLEE data download via Direct Access?

by OB.DAAC - SeanBailey » Mon Apr 10, 2017 9:43 am America/New_York

The "units" attribute in the bin file are not being properly updated for non-OC product suites (which includes the angstrom product), so this is likely this source of your confusion as to the units for ZEu.  They are in meters. 

I see that you posted a separate question about the LUT update issue, that has been responded to by another user.   Let's keep that topic separate.  If you are still having issues with the LUT update, please respond to that post.

Sean

aleitner
Posts: 8
Joined: Fri Apr 07, 2017 7:16 am America/New_York
Answers: 0

Zeu or ZLEE data download via Direct Access?

by aleitner » Tue Apr 11, 2017 12:07 am America/New_York

Thank you so much! I was very confused when I saw the units attribute.

aleitner
Posts: 8
Joined: Fri Apr 07, 2017 7:16 am America/New_York
Answers: 0

Zeu or ZLEE data download via Direct Access?

by aleitner » Tue Apr 11, 2017 1:01 am America/New_York

Thank you for your response towens. This has helped so much.

Post Reply