Preprints
https://doi.org/10.5194/egusphere-2022-1189
https://doi.org/10.5194/egusphere-2022-1189
01 Nov 2022
 | Subsequently updated
 | 01 Nov 2022 | Subsequently updated

Estimating the uncertainty of sea-ice area and sea-ice extent from satellite retrievals

Andreas Wernecke, Dirk Notz, Stefan Kern, and Thomas Lavergne

Abstract. The net Arctic sea-ice area (SIA) can be estimated from the sea-ice concentration (SIC) by passive microwave measurements from satellites. To be a truly useful metric, for example of the sensitivity of the Arctic sea-ice cover to global warming, we need, however, reliable estimates of its uncertainty. Here we retrieve this uncertainty by taking into account the spatial and temporal error correlations  of the underlying local sea ice concentration products. We find that the observational uncertainties of both sea-ice area and sea-ice extent (SIE) in 2015 are about 300 000 km2 for daily and weekly estimates and 160 000 km2 for monthly estimates. This daily uncertainty corresponds to about seven percent of the 2015 sea-ice minimum and is about half of the spread in estimated sea-ice area from different passive microwave SIC products. This shows that random SIC errors play a role in SIA uncertainties comparable to inter-SIC-product biases. We further show that the September SIA, which is traditionally the month with least Arctic sea ice, has declined by 105 000 km2 a-1 ± 9 000 km2 a-1 for the period from 2002 to 2017. This is the first estimate of a SIA trend with an explicit representation of temporal error correlations.

Andreas Wernecke, Dirk Notz, Stefan Kern, and Thomas Lavergne

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • Version 2 | 17 Nov 2023

    RC1: 'Comment on egusphere-2022-1189', Anonymous Referee #1, 26 Jan 2024
    • AC1: 'Reply on RC1', Andreas Wernecke, 18 Mar 2024
  • RC2: 'Comment on egusphere-2022-1189', Anonymous Referee #2, 04 Mar 2024
    • AC2: 'Reply on RC2', Andreas Wernecke, 18 Mar 2024
  • Version 1 | 15 Apr 2024

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • Version 2 | 17 Nov 2023

    RC1: 'Comment on egusphere-2022-1189', Anonymous Referee #1, 26 Jan 2024
    • AC1: 'Reply on RC1', Andreas Wernecke, 18 Mar 2024
  • RC2: 'Comment on egusphere-2022-1189', Anonymous Referee #2, 04 Mar 2024
    • AC2: 'Reply on RC2', Andreas Wernecke, 18 Mar 2024
  • Version 1 | 15 Apr 2024

Andreas Wernecke, Dirk Notz, Stefan Kern, and Thomas Lavergne

Model code and software

Script to create MC ensemble to represent uncertainties in ESA CCI SIC dataset Andreas Wernecke https://doi.org/10.5281/zenodo.7244321

Andreas Wernecke, Dirk Notz, Stefan Kern, and Thomas Lavergne

Viewed

Total article views: 555 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
402 126 27 555 16 14
  • HTML: 402
  • PDF: 126
  • XML: 27
  • Total: 555
  • BibTeX: 16
  • EndNote: 14
Views and downloads (calculated since 01 Nov 2022)
Cumulative views and downloads (calculated since 01 Nov 2022)

Viewed (geographical distribution)

Total article views: 562 (including HTML, PDF, and XML) Thereof 562 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 15 Apr 2024
Download
Former versions
Short summary
The total area of Arctic sea ice (SIA) is routinely monitored with the help of satellite measurements, which is an important climate indicator. Uncertainties in observations of sea-ice concentration (SIC) cancel out when averaging but the degree to which this is happening has been unclear. We calculate the uncertainty in SIA based on uncertainties in SIC and find that daily SIA estimates have uncertainties of about 300 000 km2. The 2002 to 2017 September trend is 105 000 ± 9 000 km2 per year.