data download

[Andrey Bril]

Dear colleagues,
My name is Andrey Bril,  currently I am in Minsk, Belarus
For my research, I downloaded data (Calipso lidar data) from your website.
Since I failed  to download the data directly from  your site,  I created a link like this:

http://opendap.larc.nasa.gov/opendap/CALIPSO/LID_L15-Standard-V1-01/2021/03/CAL_LID_L15-Standard-V1-01.2021-01T02-14-40ZN.hdf.nc4?Profile_UTC_Time,Latitude,Longitude,Total_Attenuated_Backscatter_532_Mean,Attenuated_Backscatter_1064_Mean,Molecular_Number_Density,

which I ran in my browser (Google Chrome). This used to work (at least last week), but now it doesn't.
I'd be grateful if you could recommend a working way to download your data.
All the best,
Andrey Bril

[Miguel Jimenez]

Hello Andrey

Thanks for reaching out. Most of NASA’s data is migrating towards the cloud and as a result the access pattern is going through a change. That means, in some cases, the data is temporarily unfindable. In most cases, that means the OPeNDAP URLs need updating.

What you will find is that the new Cloud OPeNDAP URLs have the following form:

https://opendap.earthdata.nasa.gov/collections/<CollectionConceptID>/granules/<granule_id>

Unfortunately, the website used to expose the OPeNDAP urls for the on-premises serviced to not redirect to the updated ones. Instead, discovering OPeNDAP URLs can be done in a few ways.  

To find the OPeNDAP URLs associated with the data of your interest, you will need to request these URLs from NASA’s Earthdata Search, or using known Python (open source) APIs. Will will need to know before hand : 

- Concept Collection ID of DOI of the dataset. In your case, C3880519134-LARC_CLOUD

Additional optional filters are for example: time_range, bounding boxes, of your area and time range of interest. 

For your data of interest, the Cloud OPeNDAP URLs looks like:

https://opendap.earthdata.nasa.gov/collections/C3880519134-LARC_CLOUD/granules/CAL_LID_L15-Standard-V1-01.2020-10-01T00-40-32ZN.hdf

We have also made some Python tutorials on how to find OPeNDAP URLs and stream DAP data efficiently. You can find these in our website:

- How to find OPeNDAP URLs:

https://www.opendap.org/discovering-nasa-data-to-access-via-opendap/

- How to download Calipso Aerosol (Level 2) data via OPeNDAP: 

https://www.opendap.org/access-cloud-and-aerosol-lidar-data-from-nasas-calipso/

Hope this helps, and feel free to reach out again

Best, 

Miguel

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Miguel Jimenez-Urias, PhD
Computational Oceanographer | Scientific Community Director | Software Dev
OPeNDAP, Inc

https://www.linkedin.com/in/MiguelJimenezUrias/