Seminar by Prof. Byung-Ju Sohn from School of Earth and Environmental Sciences, Seoul National University
14 August 2018
KST 14:00 – 15:30
Based on the use of analytically-derived “combined Fresnel equation”, which combines two Fresnel equations for polarized reflectivities, we were able to retrieve the ice surface temperature below the snow layer, over the Artic sea ice area. Aimed at retrieving the long-term temperature information over the Arctic sea ice region, we attempted to retrieve the sea ice temperature from 30-year long SSM/I and SSMIS FCDR (Fundamental Climate Data Record) data. In so doing we developed a linear regression model, relating AMSR-retrieved interface temperatures to SSM/I frequency channel measurements (here at 19.4 GHz), with an introduction of correction factor for removing the influences of surface roughness and volume scatterings on the measurement brightness temperature.
By applying the developed algorithm to 30 years of SSM/I and SSMIS 19.4 GHz brightness temperatures over the Arctic sea ice region, winter time (December-January-February) daily sea ice surface temperature data were produced. Initial results indicate that there is a rapid warming of sea ice, much faster than surface air temperature (SAT); a continuous and dramatic increase of up to 1.37K/decade over the Arctic Ocean is found over the 30-year period (1987-2017), with a clear global warming hiatus signal between 1998 and 2012. This may be the first Arctic Ocean-wide picture showing how the Arctic amplification has been evolved. I will present how the results may be used for understanding the Arctic amplification.