[Q] TEMPO_RADT_L1 OPeNDAP Service?

[hyoklee]

https://cmr.earthdata.nasa.gov/search/concepts/C3868234842-LARC_CLOUD.html# says

```
Associated Services
Concept ID Name Type
S2874702816-XYZ_PROV OPeNDAP NOT PROVIDED
```

Does anyone know when the OPeNDAP service will be available?

[ASDC - ghayescrepps]

Thank you for your question. OPeNDAP is currently available for the TEMPO RADT L1 data. I think the confusion may be from json response you posted. The "Not Provided" refers to the the Service Type and indicates that OPeNDAP does not have a further type classification in CMR; however, the service is connected and available for use. Please let us know if you have any issues using the OPeNDAP service.

[hyoklee]

I'm happy to hear that the service is available.
What's the OPeNDAP server's URL?

I can't locate it from https://www.earthdata.nasa.gov/engage/open-data-services-software/earthdata-developer-portal/opendap/servers

https://l0dup05.larc.nasa.gov/opendap/ returns 404.

[ASDC - ghayescrepps]

As TEMPO data are in the cloud, these data are available through OPeNDAP in the cloud, which is set up a bit differently than the link you posted, which is an on-prem OPeNDAP instance.

But one of the main differences is that currently, the OPeNDAP in the cloud does not offer collection-based landing pages; each granule in a collection has its own landing page only. This, therefore requires a different approach to selecting and subsetting granules.

For example, this is one RADT OPeNDAP URL: https://opendap.earthdata.nasa.gov/collections/C3868234842-LARC_CLOUD/granules/TEMPO_RADT_L1_V04_20260430T013937Z_S018G03.nc.dmr

This post provides a bit more information: viewtopic.php?t=3901 (it also contains a link to an additional tutorial). There are also some code examples: https://github.com/podaac/tutorials/blob/master/notebooks/opendap/MUR-OPeNDAP.ipynb

[hyoklee]

Thank you for the OPeNDAP link and tips.

However, I can't access it with Panoply.
Does anyone know why?

I tried both old (5.5.4) & latest (5.9.2) versions of Panoply.

[hyoklee]

I could fix the above issue by replacing `http://` with `dap4://`.

However, I got another `Could not read longitude array` error.

Does anyone know why?

[ASDC - ghayescrepps]

Can you please send the exact URL you are using so we can try to replicate the error? I tried displaying the radiance variable from the netcdf directly, and that works, so there may be something incorrect in the opendap method.

Also, did you try to open this granule more than once? Do you always get this same error? And did you try other granules--does this occur for any that you try?

[hyoklee]

Hi, thank you for looking into this.

I'm using "Open Remote Dataset...(CTRL+L)" in Panoply.

I entered the following URL because `https` did not work:

dap4://opendap.earthdata.nasa.gov/collections/C3868234842-LARC_CLOUD/granules/TEMPO_RADT_L1_V04_20260430T013937Z_S018G03.nc

Then, I entered Earthdata username and password. Click "band_290_490_nm". Click "radiance".

[mikejmnez]

Hi - I have no trouble accessing the data from the OPeNDAP service directly. It is not clear what the issue is. But I wrote a python tutorial that:

- Finds ~300 cloud opendap granules from a TEMPO L2 (near real time) collection.
- Subsets spatially
- Subsets by variable name
- Streams subset data into your local machine

All within 2-5 minutes. Here is the link, if you are interested:

https://www.opendap.org/access-near-real-time-air-quality-data-from-nasas-tempo-mission/

This workflow can be run interactively, and can surely be adapted for this specific TEMPO L1 collection (different variable names, etc).

[ASDC - andrey.kim]

Hi, did you use this feature (open remote dataset) successfully with other opendap collections before? If yes, could you provide the link?
Thank you