Can we extend local sea-ice measurements to satellite scale? An example from the N-ICE2015 expedition

Anja Rösel,Anthony P Doulgeris,A Malin Johansson,Penelope M Wagner,Sebastian Gerland,Jennifer King

doi:10.1017/aog.2017.37

Abstract

ABSTRACTKnowledge of Arctic sea-ice conditions is of great interest for Arctic residents, as well as for commercial usage, and to study the effects of climate change. Information gained from analysis of satellite data contributes to this understanding. In the course of using in situ data in combination with remotely sensed data, the question of how representative local scale measurements are of a wider region may arise. We compare in situ total sea-ice thickness measurements from the Norwegian young sea ICE expedition in the area north of Svalbard with airborne-derived total sea-ice thickness from electromagnetic soundings. A segmented and classified synthetic aperture radar (SAR) quad-pol ALOS-2 Palsar-2 satellite scene was grouped into three simplified ice classes. The area fractions of the three classes are: 11.2% ‘thin’, 74.4% ‘level’, and 14.4% ‘deformed’. The area fractions of the simplified classes from ground- and helicopter-based measurements are comparable with those achieved from the SAR data. Thus, this study shows that there is potential for a stepwise upscaling from in situ, to airborne, to satellite data, which allow us to assess whether in situ data collected are representative of a wider region as observed by satellites.

Highlights

The changing sea-ice conditions in the Arctic (e.g. Perovich and others, 2016) are of interest for shipping companies, fishery, the oil and gas industry, and local residents
The primary mode is at 1.7 m for both, but HEM24 has a second mode at 2.0 m, and a third one at between 0.2 and 0.4 m, matching the mode in the same range in the EM31 distribution (Table 2)
The results have been classified into three simplified classes and compared with a segmented and classified ALOS-2 Synthetic aperture radar (SAR) scene

Summary

Introduction

The changing sea-ice conditions in the Arctic (e.g. Perovich and others, 2016) are of interest for shipping companies, fishery, the oil and gas industry, and local residents. In order to extend our understanding of sea-ice conditions to the satellite scale, is is necessary to ascertain how well those in situ and airborne measurements represent the different classes that can be identified following segmentation and analysis of the image.

Results

Conclusion