Help retrieving ArcGIS data for Sea Surface Salinity

Help retrieving ArcGIS data for Sea Surface Salinity

Postby podaac » Mon Jan 11, 2016 10:32 pm

User Question:
I am an undergraduate at San Francisco State University and I was trying to find easy way to find and upload into ArcGIS data for sea surface salinity.

There are a few agencies that have data but I've gotten overwhelmed by it all.

Any help with getting monthly average salinity sea surface data for the San Francisco Bay and Delta region for years 2008-2015?

I'm sure it is relatively easy to access and work with these files, but with my level of experience, it's hard to process all the options.

Reply:
Thanks for your inquiry to PO.DAAC on the availability of monthly mapped Sea Surface Salinity data from Aquarius for your region of interest.

The recommended product is the "Aquarius Official Release Level 3 Sea Surface Salinity Standard Mapped Image Monthly Data V4.0 (AQUARIUS_L3_SSS_SMI_MONTHLY_V4)" . It spans the period 2011-Aug-25 to 2015-Jun-7.

The following URL takes you to our portal catalog entry for this dataset where you can find descriptions and pointers to documentation plus information on how to access the data, including via ftp and Webservices such as THREDDS and OPenDAP
https://podaac.jpl.nasa.gov/dataset/AQU ... MONTHLY_V4.

The one thing to note about the Aquarius Level 3/Gridded products is that the spatial resolution is relatively course at 1x1 degree Lat/Lon. This partly reflects the fact that the Aquarius/SAC-D mission was designed with a principal focus on oceanic salinity observation. The lower spatial resolution of the Aquarius data (1 degree Lat/Lon for L3 gridded data and about 70x70km for L2 swath/orbital data), 7day repeat cycle and some technical issues associated with salinity retrieval near land ("land contamination" and in some areas also "RFI interference") limits the potential applicability of Aquarius data for near-shore areas. So you will need to evaluate, given the location/extent of your study area, whether the resolution and coverage of the available data meet the needs of your application with its San Francisco Bay focus. If yes, then please read on ...

Like all Aquarius L3 (gridded) products, these data are natively available in HDF5 format as global files. Further details on the structure of the data is available in the Aquarius V4.0 Data Users Guide (.pdf) available from:
https://podaac-tools.jpl.nasa.gov/drive ... etV4.0.pdf

Since you are interested in a spatial subset for your region, I suggest you use the THREDDS Subsetting Service (NCSS) to interactively extract the monthly wind speed data for the area and time period of interest via the following link...

https://thredds.jpl.nasa.gov/thredds/ca ... LY_V4.ncml

This should be straightforward to use, but for a tutorial see my article "THREDDS: Web-based data subsetting How-To" (viewtopic.php?f=5&t=175) on the PO.DAAC forum.
Output will be a single netCDF data file with a series of 2D ("l3m_data") arrays containing the native 1 degree spatial resolution sea_surface_salinity data, dimensioned by time, lat, lon extents as specified by your query.

Note that we do have another tool called LAS (https://podaac.jpl.nasa.gov/las) which provides a web-based means of undertaking such extractions and also visualizing the data, but unfortunately this is down for maintenance. Just wanted to let you know though for the future that this tool allows one to export the data additionally in ArcGRID and ASCII/CSV formats.

Regarding ArcGIS:
While we don't support/work with ArcGIS here at PO.DAAC, so cant advise much on that front. However, I do believe that ArcGIS now natively can read and display HDF and netCDF data files (see http://help.arcgis.com/EN/arcgisdesktop ... 0014000000). I am also aware of a free ArcGIS plugin developed by NOAA called EDC (Environmental Data Connector) that could be leveraged to read in netCDF and HDF data files related to Aquarius SSS. You can read the User Guide for this tool and download the software from...
http://www.pfeg.noaa.gov/products/EDC/EDCdownloads.html
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Re: Help retrieving ArcGIS data for Sea Surface Salinity

Postby beckham2000 » Mon Oct 02, 2017 4:21 pm

The article is quite useful.
Thank you for the information you shared.
G9!
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