|Paper title||A combined Sea and Ice Surface Temperature climate data set for the Arctic Ocean|
|Form of presentation||Poster|
The Arctic has warmed more than twice the global rate, which makes it a crucial region to monitor surface temperatures in this region. Global surface temperature products are fundamental for assessing temperature changes, but for the Arctic sea ice these products are traditionally only built on near-surface air temperature measurements from weather stations and sparse drifting buoy temperature measurements. However, only limited in situ observations are actually available in the Arctic due to the extreme weather conditions and limited access. Therefore, satellite observations have a large potential to improve the surface temperature estimates in the Arctic Ocean due to the good temporal and spatial coverage.
We present the first satellite derived combined and gap-free (L4) climate data set of sea surface temperatures (SST) and ice surface temperatures (IST) covering the Arctic Ocean (>58°N) for the period 1982-2021. The derived L4 SST/IST climate data set has been generated as a part of the Copernicus Marine Environment Monitoring Service (CMEMS) and the National Centre for Climate Research (NCKF). The data set has been generated by combining multi-satellite observations using statistical optimal interpolation (OI) to obtain daily gap-free fields with a spatial resolution of 0.05°. Due to the different characteristics of the open ocean, sea ice and the marginal ice zone (MIZ), the OI statistical parameters have been derived separately for each region. Therefore, it is very important with an accurate sea ice concentration (SIC) field for identifying the regions. Here, a combination of several SIC products and additional filtering have been used to produce an improved SIC product.
Observations from drifting buoys, moored buoys, ships and the Icebridge campaigns have been used to validate the L4 SST/IST over the ocean and sea ice. The combined sea and ice surface temperature of the Arctic Ocean provides a consistent climate indicator which can be used to monitor day-to-day variations as well as long term climate trends. The combined sea and ice surface temperature of the Arctic Ocean has increased with more than 4°C over the period from 1982 to 2021.