New insights into the quantitative description of seasonal sea ice variability process in the semi-closed Kara Sea

Abstract

The sea ice has a large seasonal variability in the semi-closed Kara Sea. The previous studies focused mainly on the climatic ice coverage characteristics and the associated relationship with the governing thermodynamic and dynamic factors. However, information on the statistical model of the sea ice coverage growth and decay curve is lacking. Thus, the Logistic curve model is firstly suggested to quantify this sea ice growth and decay process in the Kara Sea. Results show that the fitted ice coverage variability curves have good performance in terms of the small MAE (<0.04), RMSE (<0.04), and high R2 (>0.97). For the growth process, the fitted growth curves derived from the standard Logistic curve model are in good agreement with the observed data during the entire 40 years (1979–2018), and each decade (1979–1988, 1989–1998, 1999–2008, and 2009–2018). For the decay process, the relevant fitted decay curves derived from the inverted Logistic curve model are also in good consistent with the observed data during the above different time periods. Specifically, both the rapid ice coverage increase pattern during the growth process and the remarkable decrease pattern during the decay process are successfully characterized by the corresponding fitted curves. The quantitative mathematical functions of the seasonal sea ice variability process in the Kara Sea are determined with the different estimated parameters.