NSIDC Sea Ice Concentrations from Passive Microwave Data

This code package is in development and the API is subject to change without notice. There is no guarantee that this code works as expected. The addition of tests and verification of outputs is still in progress.

The code here creates sea ice concentration estimates from passive microwave data using code adapted from NASA Goddard's Bootstrap and NASA Team algorithms.

For more informaton about Bootstrap and NASA Team algorithms, see Descriptions of and Differences between the NASA Team and Bootstrap Algorithms

There is a long history to this project! Comments may indicate references to "CDR v4" or "Goddard". In short:

• NASA Goddard Space Flight Center (GSFC) originally developed the algorithms
• NSIDC developed pmalgos (currently private repo) in the late ~1990s from the code Goddard developed.
• More recently, NSIDC developed cdralgos (private repo) based on pmalgos and newly updated code from Goddard (Goddard contnued to develop and run their own code)
• Now, this iteration, which seeks to replicate the sea ice concentration algorithms in Python, and in a modular fashion.

Level of Support

This repository is not actively supported by NSIDC but we welcome issue submissions and pull requests in order to foster community contribution.

See the LICENSE for details on permissions and warranties. Please contact nsidc@nsidc.org for more information.

Requirements

This code relies on the python packages defined in the included environment.yml file.

Use conda to install the requirements:

$ conda env create

Installation

First, Activate the conda environment:

$ conda activate pm_icecon

Usage

Bootstrap

Users can write a script using the functions provided in this repo to run the bootstrap algorithm. The main entrypoint to the bootstrap algorithm is the bootstrap function defined in pm_icecon/bt/compute_bt_ic.py.

For an example of how to write a script to convert a2l1c tbs into a concentration field, see scripts/example_bt_script.py.

Additional examples are in pm_icecon/bt/api.py. Note that as of this time, all functions defined in the the api module are specifically setup to use hard-coded defaults for testing purposes at NSIDC. This includes paths to data on NSIDC infrastructure that are not available to the public.

Nasateam

The main entrypoint to running the nasateam code on input Tbs is the nasateam function defined in pm_icecon/nt/compute_nt_ic.py.

An API has also been defined for common use cases. See pm_icecon/nt/api.py for more information. NOTE: the API is currently defined with hard-coded defaults that expect access to NSIDC's virtual machine infrastructure and should be used with caution.

Development/contributing

See doc/development.md for more information.

License

See LICENSE.

Code of Conduct

See Code of Conduct.

Credit

This software was developed by the National Snow and Ice Data Center with funding from NASA and NOAA.

The original Bootstrap and NASA Team algorithms were developed by researchers at the NASA Goddard Space Flight Center. NASA Goddard provided the original code to NSIDC where it has been adapted and modernized for processing at NSIDC.

For more information on the NASA Team and Bootstrap algorithms, please consult the following references, respectively:

Cavalieri, D. J., Gloersen, P., and Campbell, W. J. (1984), Determination of sea ice parameters with the NIMBUS 7 SMMR, J. Geophys. Res., 89( D4), 5355– 5369, doi:10.1029/JD089iD04p05355.

Comiso, J. C. 1995. SSM/I Concentrations Using the Bootstrap Algorithm. NASA Reference Publication 1380. 40 pg. Available from: https://www.geobotany.uaf.edu/library/pubs/ComisoJC1995_nasa_1380_53.pdf