The impact of a thermodynamic sea-ice module in the COSMO numerical weather prediction model on simulations for the Laptev Sea, Siberian Arctic

• Published in: Polar Research
• Main Authors: Schröder, David, Heinemann, Günther, Willmes, Sascha
• Format: Article in Journal/Newspaper
• Language: English
• Published: Norwegian Polar Institute 2011
• Subjects: Arctic; Laptev Sea; laptev; Polar Research; Sea ice
• Online Access: https://oceanrep.geomar.de/id/eprint/26341/; https://oceanrep.geomar.de/id/eprint/26341/1/2011_Schoeder-Heinemann-Willmes_6334-20924-1-PB.pdf; https://doi.org/10.3402/polar.v30i0.6334

Previous versions of the Consortium for Small-scale Modelling (COSMO) numerical weather prediction model have used a constant sea-ice surface temperature, but observations show a high degree of variability on sub-daily timescales. To account for this, we have implemented a thermodynamic sea-ice module in COSMO and performed simulations at a resolution of 15 km and 5 km for the Laptev Sea area in April 2008. Temporal and spatial variability of surface and 2-m air temperature are verified by four automatic weather stations deployed along the edge of the western New Siberian polynya during the Transdrift XIII-2 expedition and by surface temperature charts derived from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data. A remarkable agreement between the new model results and these observations demonstrates that the implemented sea-ice module can be applied for short-range simulations. Prescribing the polynya areas daily, our COSMO simulations provide a high-resolution and high-quality atmospheric data set for the Laptev Sea for the period 14–30 April 2008. Based on this data set, we derive a mean total sea-ice production rate of 0.53 km3/day for all Laptev Sea polynyas under the assumption that the polynyas are ice-free and a rate of 0.30 km3/day if a 10-cm-thin ice layer is assumed. Our results indicate that ice production in Laptev Sea polynyas has been overestimated in previous studies.