Study on Sea Ice Extraction and Area Correction Model Based on MODIS and GF Data

Abstract

To gain correct sea ice data, high time resolution (MODIS) and high spatial resolution (GF-2) materials are combined to achieve wide-range high precision monitoring of sea ice area in Liaodong Bay. This article takes GF-2 sea ice area as the baseline, intercepts corresponding MODIS sea ice monitoring scope, establishes a sea ice area correction model, and conducts long time series’ analysis of sea ice area change. Here’s the result: spectral observation result shows that comparing with CH2 channel, spectral reflectance of the snow-covering sea ice, ice-water mixture, seawater and sea ice in CH1 are with a greater difference value and easier to distinguish. Comparing with the accuracy of 3 extraction methods of MODIS sea ice, the optimal method is CH1 single channel extraction. This paper takes the sea ice area extracted by GF-2 satellite as the benchmark data, then establishes a MODIS sea ice area correction model. The model’s correlation coefficient is 0.96. The monitoring error after correction is reduced from 39% to 10%. Sea ice area change in long time sequence shows that the sea ice area of Liaodong Bay is in slight downtrend. The inter-annual variation is featured with 4 years’ periodical change. In every winter, sea ice area is in unimodal change, and reaches the maximum value in about early Feb.