Modeling the Summertime Sea Ice Melt-Water Ponds

Melt ponds are the most distinctive summertime feature of Arctic sea ice. Pond-covered sea ice preferentially absorbs short-wave solar radiation and this explains why the melt rate beneath melt ponds is 2-3 times that of bare sea ice. Melt ponds influence salinity variation of sea ice and can drain, releasing relatively fresh water into the upper layers of the ocean. Fresh melt water draining through sea ice can lead to the formation of under-ice melt ponds. For these reasons melt ponds are an important element of the Arctic climate system and attract our attention as an important subject for investigation. Modeling the evolution of melt ponds as the main process associated with significant changes in albedo, is currently one of the possible improvement of accuracy of climate models and thus the quality of predictions. The aim of this work is to improve parameterizations of the formation and summertime evolution of melt ponds on sea ice. As a result of this research work the following tasks solved: a new parameterization for the sea ice melting modules of the thermodynamic model of sea-ice (AARI), the calculation of the sea ice evolution and heat balance of the surface in the presence of melt ponds with the help of Mathematica and comparing the results of numerical calculations with the results of the model NAOSIM developed at the Alfred Wegener Institute for Polar and Marine Research (AWI, Bremerhaven, Germany). Comparing the results of three models, the following conclusions can be drawn: • Significant difference in the values of ice thickness in two models show us that the results of models are sensitive to the parameterization melting layer on the surface of ice cover in summer. At the same time due to lack of field observations it is impossible to decide which model gives more accurate results; • Short-wave radiation and temperature obtained with the use of melt pond depthdepended albedo parameterization demonstrate the importance of this kind of parameterization. Hence there is a necessity of different mathematical schemes for solving the system of differential equations; It is necessary to derive the parameterization of the drainage rate depending on such characteristics of ice, such as the height above sea level (hydrostatic pressure), the permeability or thickness of ice, or reflect the change of the rate as melt progresses