Application of the PIP25 index for reconstructing spring sea ice concentration in the western Arctic Ocean

Abstract

Arctic sea ice plays an important role in the global climate system via the sea ice-albedo feedback. Reliable satellite-derived records of the Arctic sea-ice extent have only been available since 1979. Hence, reconstructions of sea ice conditions on time scales beyond satellite measurements are necessary to understand natural, longer-term sea ice changes and their driving mechanisms under various climate forcings. In this study, we investigated 53 surface sediments collected from the Chukchi Sea and the East Siberian Sea during the Arctic cruises with RV Araon from 2010 to 2019. We aimed to assess the applicability of the PIP25 index, based primarily on the use of HBI III as a semiquantitative sea ice proxy in the western Arctic Ocean. Our preliminary results showed the presence of IP25 in all sediment samples investigated, confirming the occurrence of seasonal sea ice in the study area. Nonetheless, further works are necessary to establish a regional balance factor c value, a term used to calculate the PIP25 index in the western Arctic Ocean.