Daily Edge of Each Polynya in Antarctic (DEEP-AA)

The dataset of Daily Edge of Each Polynya in Antarctic (DEEP-AA) maps the area of each polynya daily. It uses a polynya tracking and identification method proposed by Lin et al., and effectively records the daily areas of both frequent and infrequent polynyas in wintertime (April to October). The DEEP-AA spans from 2003 to 2022 (2011.09.01-2012.07.31 missed). 

It should be noticed that ONLY the dataset of  SIC60_6.25km_20d.zip is recommended, and the other ones used only in sensitive anaylsis were NOT parameter tuned. Be careful to use sets other than SIC60_6.25km_20d.zip.

You can get the codfe to create the dataset from the Github release.

A description of the dataset has been published: Lin, Y. et al. A dataset of the daily edge of each polynya in the Antarctic. Sci. Data 11, 1006 (2024).

Contents in DEEP-AA

DEEP-AA

Subsets (*.zip)

Daily maps (DEEP_*.nc)

OverviewMap.mat

Input.txt

Subsets

Multiple subsets (*.zip) under various parameter settings are provided here. Among them, SIC60_6.25km_20d.zip is recommended. Its spatial resolution is 6.25 km (polar stereographic grid, EPSG code 3412) and the temporal resolution is 1 day. This subset is built based on sea ice concentration data from the University of Bremen (https://doi.org/10.1594/PANGAEA.919778, and https://doi.org/10.1594/PANGAEA.898400), combined with ERA5 2m air temperature (https://doi.org/10.24381/cds.adbb2d47), Circum-Antarctic landfast sea ice extent, 2000-2018 - version 2.2 (https://doi.org/doi:10.26179/5d267d1ceb60c), and U.S. National Ice Center Arctic and Antarctic Sea Ice Concentration and Climatologies in Gridded Format, Version 1 (https://doi.org/10.7265/46cc-3952).

The other subsets are the results of simple parameter modification (1 or 2 parameters) based on the setting of SIC60_6.25km_20d.zip. You can get detailed parameter settings in the Input.txt in every subset.

Files of each subset

Daily maps (DEEP_*.nc)

DEEP-AA provides a NetCDF file daily containing a polynya map for that day. We give each polynya a 9-bit unique ID that does not change over time, and in the daily maps, the area of each polynya is masked by its ID. The last bit of the ID also represents the attributes of the polynya: the even number indicates coastal polynya, odd number indicates open-ocean polynya.

In addition, the other open water, open sea, lands, etc. are also recorded in the maps. See details in the following table:

Value
Meanings

>0, even number
coastal polynya ID mask

>0, odd number
open-ocean polynya ID mask

-100
mask of landfast ice

-2
open sea

-1
the other open waters (not polynyas)

NaN or -999
mask of lands

OverviewMap.mat

An overview map of all polynyas identified. It maps all the Antarctic polynyas in that subset by their ID masks. You can run the MATLAB script PolynyaIDsFinder_Guide.m to view it and inquire about polynyas' IDs easily.

Input.txt

It records the parameters used to create the subset.