The idea of Pangeo Forge is to copy the very successful pattern of Conda Forge for crowdsourcing the curation of an analysis-ready data library.
In Conda Forge, a maintainer contributes a recipe which is used to generate a conda package from a source code tarball. Behind the scenes, CI downloads the source code, builds the package, and uploads it to a repository.
In Pangeo Forge, a maintainer contributes a recipe which is used to generate an analysis-ready cloud-based copy of a dataset in a cloud-optimized format like Zarr. Behind the scenes, CI downloads the original files from their source (e.g. FTP, HTTP, or OpenDAP), combines them using xarray, writes out the Zarr file, and uploads to cloud storage.
There are many details to work out. It is useful to think about what ingredients might go into a recipe.
Sample meta.yaml recipe.
dataset:
# should be a unique name and valid python identifier
name: noaa_oisst_avhrr_only
# how should we version datasets?
version: 0.1.0
# where do we find the files
source:
format: netcdf
# example: https://www.ncei.noaa.gov/data/sea-surface-temperature-optimum-interpolation/access/avhrr-only/198109/avhrr-only-v2.19810901.nc
url_pattern: https://www.ncei.noaa.gov/data/sea-surface-temperature-optimum-interpolation/access/avhrr-only/{{ yyyymm }}/avhrr-only-v2.{{ yyyymmdd }}.nc
# mirror pandas syntax
# https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.date_range.html
date_range:
start: 1981-09-01
# the end date can
end: 2019-08-11
freq: D
# tell xarray how to open and combine the files
combine:
# options passed to xarray.open_dataset
open_options:
decode_cf: False
combine_method: combine_by_coords
# options passed to combine method
combine_options:
compat: no_conflicts
# where / how to save the data
output:
format: zarr
chunks:
time: 5
consolidated: True
target:
urlpath: gcs://pangeo-noaa/
# how to deal with credentials?
credentials: ???
about:
home: https://www.ncdc.noaa.gov/oisst
# how to deal with licensing?
license: ???
summary: 'NOAA Optimally Interpolated Sea Surface Temperature (AVHRR Only)'
description: |
The NOAA 1/4° daily Optimum Interpolation Sea Surface Temperature (or daily OISST) is an analysis constructed by combining observations from different platforms (satellites, ships, buoys) on a regular global grid. A spatially complete SST map is produced by interpolating to fill in gaps.
The methodology includes bias adjustment of satellite and ship observations (referenced to buoys) to compensate for platform differences and sensor biases. This proved critical during the Mt. Pinatubo eruption in 1991, when the widespread presence of volcanic aerosols resulted in infrared satellite temperatures that were much cooler than actual ocean temperatures (Reynolds 1993).
support_email: oisst-help@noaa.gov