ICESat-2 AWS cloud data access

This notebook (download) illustrates the use of icepyx for accessing ICESat-2 data currently available through the AWS (Amazon Web Services) us-west2 hub s3 data bucket.

Notes

  1. ICESat-2 data became publicly available on the cloud on 29 September 2022. Thus, access methods and example workflows are still being developed by NSIDC, and the underlying code in icepyx will need to be updated now that these data (and the associated metadata) are available. We appreciate your patience and contributions (e.g. reporting bugs, sharing your code, etc.) during this transition!

  2. This example and the code it describes are part of ongoing development. Current limitations to using these features are described throughout the example, as appropriate.

  3. You MUST be working within an AWS instance. Otherwise, you will get a permissions error.

  4. Cloud authentication is still more user-involved than we’d like. We’re working to address this - let us know if you’d like to join the conversation!

import earthaccess
import icepyx as ipx

Create an icepyx Query object

# bounding box
# "producerGranuleId": "ATL03_20191130221008_09930503_004_01.h5",
short_name = 'ATL03'
spatial_extent = [-45, 58, -35, 75]
date_range = ['2019-11-30','2019-11-30']

reg=ipx.Query(short_name, spatial_extent, date_range)

Get the granule s3 urls

You must specify cloud=True to get the needed s3 urls. This function returns a list containing the list of the granule IDs and a list of the corresponding urls.

gran_ids = reg.avail_granules(ids=True, cloud=True)
gran_ids

Log in to Earthdata and generate an s3 token

You can use icepyx’s existing login functionality to generate your s3 data access token, which will be valid for one hour.

We currently do not have this set up to automatically renew, but earthaccess, which icepyx uses under the hood for authentication, is working on handling the limits imposed by expiring s3 tokens. If you’re interested in working on helping icepyx and earthaccess address these challenges, please get in touch or submit a PR. Documentation/example testers are always appreciated (so you don’t have to understand the code)!

reg.earthdata_login(s3token=True)

Set up your s3 file system using your credentials

s3 = earthaccess.get_s3fs_session(daac='NSIDC', provider=reg._s3login_credentials)

Select an s3 url and access the data

Data read in capabilities for cloud data are coming soon in icepyx (targeted Spring 2023). Stay tuned and we’d love for you to join us and contribute!

Note: If you get a PermissionDenied Error when trying to read in the data, you may not be sending your request from an AWS hub in us-west2. We’re currently working on how to alert users if they will not be able to access ICESat-2 data in the cloud for this reason

# the first index, [1], gets us into the list of s3 urls
# the second index, [0], gets us the first entry in that list.
s3url = gran_ids[1][0]
# s3url =  's3://nsidc-cumulus-prod-protected/ATLAS/ATL03/004/2019/11/30/ATL03_20191130221008_09930503_004_01.h5'

import h5py
import numpy as np

%time f = h5py.File(s3.open(s3url,'rb'),'r')

Credits

  • notebook by: Jessica Scheick

  • historic source material: is2-nsidc-cloud.py by Brad Lipovsky