A lead-width distribution for Antarctic sea ice: a case study for the Weddell Sea with high resolution Sentinel-2 images
We derive for the first time a statistical lead-width distribution for Antarctic sea ice using Weddell sea ice as a case study. Therefore, we transfer previous approaches for Arctic sea ice with a power law with a positive exponent ( p ( x width ) x width − a , a > 1) to Antarctic sea ice. We use...
| Main Authors: | , , |
|---|---|
| Format: | Text |
| Language: | English |
| Published: |
2020
|
| Subjects: | |
| Online Access: | https://doi.org/10.5194/tc-2020-222 https://tc.copernicus.org/preprints/tc-2020-222/ |
| Summary: | We derive for the first time a statistical lead-width distribution for Antarctic sea ice using Weddell sea ice as a case study. Therefore, we transfer previous approaches for Arctic sea ice with a power law with a positive exponent ( p ( x width ) x width − a , a > 1) to Antarctic sea ice. We use 20 carefully selected cloud-free Copernicus Sentinel-2 images from November 2016 until February 2018, covering only the months from November to April. In doing so we compare exponents given in the literature for the Arctic sea ice, who do not agree with each other, to Antarctic sea ice. To detect leads we create a sea ice surface type classification for the Sentinel-2 Level 1C data products, which are selected due to their high spatial resolution of 10 m. We apply two different fitting methods to the measured lead widths, which have been used in previous studies for Arctic sea ice. The first fitting method is a linear fit, while the second method is based on a maximum likelihood approach. Here, we use both methods for the same lead-width data set to observe differences in the calculated power law exponent. To further investigate influences on the power law exponent, we define two different lead thresholds for open water and nilas. The influence of the lead threshold on the exponent is bigger for the linear fit than for the method based on the maximum likelihood approach. We show that the exponent of the lead-width distribution ranges between 1.16 to 1.41 depending on the applied fitting method and lead threshold. This exponent for the Weddell sea ice is smaller than the previously observed exponents for the Arctic sea ice. |
|---|